diff --git a/Earthfile b/Earthfile
index 6b45cabafd..af5c0340c4 100644
--- a/Earthfile
+++ b/Earthfile
@@ -27,7 +27,7 @@ install-zig-llvm-valgrind-clippy-rustfmt:
     RUN echo "[build]" > $CARGO_HOME/config.toml
     RUN echo "rustflags = [\"-C\", \"link-arg=-fuse-ld=lld\", \"-C\", \"target-cpu=native\"]" >> $CARGO_HOME/config.tom
     # valgrind
-    RUN apt -y install autotools-dev cmake automake 
+    RUN apt -y install autotools-dev cmake automake libc6-dbg
     RUN wget https://sourceware.org/pub/valgrind/valgrind-3.16.1.tar.bz2
     RUN tar -xf valgrind-3.16.1.tar.bz2
     # need to cd every time, every command starts at WORKDIR
diff --git a/cli/tests/cli_run.rs b/cli/tests/cli_run.rs
index ecaf3e3062..ef11fade5d 100644
--- a/cli/tests/cli_run.rs
+++ b/cli/tests/cli_run.rs
@@ -96,7 +96,7 @@ mod cli_run {
             "hello-world",
             &[],
             "Hello, World!!!!!!!!!!!!!\n",
-            false,
+            true,
         );
     }
 
@@ -108,7 +108,7 @@ mod cli_run {
             "hello-world",
             &[],
             "Hello, World!!!!!!!!!!!!!\n",
-            false,
+            true,
         );
     }
 
@@ -120,7 +120,7 @@ mod cli_run {
             "quicksort",
             &[],
             "[0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2]\n",
-            false,
+            true,
         );
     }
 
@@ -132,28 +132,12 @@ mod cli_run {
             "quicksort",
             &["--optimize"],
             "[0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2]\n",
-            false,
-        );
-    }
-
-    #[test]
-    #[serial(quicksort)]
-    // TODO: Stop ignoring this test once we are correctly freeing the RocList even when in dev build.
-    #[ignore]
-    fn run_quicksort_valgrind() {
-        check_output(
-            &example_file("quicksort", "Quicksort.roc"),
-            "quicksort",
-            &[],
-            "[0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2]\n",
             true,
         );
     }
 
     #[test]
     #[serial(quicksort)]
-    // TODO: Stop ignoring this test once valgrind supports AVX512.
-    #[ignore]
     fn run_quicksort_optimized_valgrind() {
         check_output(
             &example_file("quicksort", "Quicksort.roc"),
@@ -164,34 +148,6 @@ mod cli_run {
         );
     }
 
-    #[test]
-    #[serial(multi_module)]
-    // TODO: Stop ignoring this test once we are correctly freeing the RocList even when in dev build.
-    #[ignore]
-    fn run_multi_module_valgrind() {
-        check_output(
-            &example_file("multi-module", "Quicksort.roc"),
-            "quicksort",
-            &[],
-            "[0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2]\n",
-            true,
-        );
-    }
-
-    #[test]
-    #[serial(multi_module)]
-    // TODO: Stop ignoring this test once valgrind supports AVX512.
-    #[ignore]
-    fn run_multi_module_optimized_valgrind() {
-        check_output(
-            &example_file("multi-module", "Quicksort.roc"),
-            "quicksort",
-            &["--optimize"],
-            "[0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2]\n",
-            true,
-        );
-    }
-
     #[test]
     #[serial(nqueens)]
     fn run_nqueens_not_optimized() {
@@ -201,7 +157,7 @@ mod cli_run {
             "nqueens",
             &[],
             "4\n",
-            false,
+            true,
         );
     }
 
@@ -213,7 +169,7 @@ mod cli_run {
             "cfold",
             &[],
             "11 & 11\n",
-            false,
+            true,
         );
     }
 
@@ -237,7 +193,7 @@ mod cli_run {
             "rbtree-insert",
             &[],
             "Node Black 0 {} Empty Empty\n",
-            false,
+            true,
         );
     }
 
@@ -249,7 +205,7 @@ mod cli_run {
             "rbtree-del",
             &[],
             "30\n",
-            false,
+            true,
         );
     }
 
@@ -272,7 +228,7 @@ mod cli_run {
             "multi-dep-str",
             &[],
             "I am Dep2.str2\n",
-            false,
+            true,
         );
     }
 
@@ -284,7 +240,7 @@ mod cli_run {
             "multi-dep-str",
             &["--optimize"],
             "I am Dep2.str2\n",
-            false,
+            true,
         );
     }
 
@@ -296,7 +252,7 @@ mod cli_run {
             "multi-dep-thunk",
             &[],
             "I am Dep2.value2\n",
-            false,
+            true,
         );
     }
 
@@ -308,7 +264,7 @@ mod cli_run {
             "multi-dep-thunk",
             &["--optimize"],
             "I am Dep2.value2\n",
-            false,
+            true,
         );
     }
 }
diff --git a/compiler/gen/src/llvm/build.rs b/compiler/gen/src/llvm/build.rs
index cb52cec7e1..15575694e6 100644
--- a/compiler/gen/src/llvm/build.rs
+++ b/compiler/gen/src/llvm/build.rs
@@ -661,7 +661,7 @@ pub fn build_exp_literal<'a, 'ctx, 'env>(
 pub fn build_exp_call<'a, 'ctx, 'env>(
     env: &Env<'a, 'ctx, 'env>,
     layout_ids: &mut LayoutIds<'a>,
-    scope: &Scope<'a, 'ctx>,
+    scope: &mut Scope<'a, 'ctx>,
     parent: FunctionValue<'ctx>,
     layout: &Layout<'a>,
     call: &roc_mono::ir::Call<'a>,
@@ -732,16 +732,29 @@ pub fn build_exp_call<'a, 'ctx, 'env>(
         }
 
         CallType::Foreign {
-            foreign_symbol: foreign,
+            foreign_symbol,
             ret_layout,
-        } => build_foreign_symbol(env, scope, foreign, arguments, ret_layout),
+        } => {
+            // we always initially invoke foreign symbols, but if there is nothing to clean up,
+            // we emit a normal call
+            build_foreign_symbol(
+                env,
+                layout_ids,
+                scope,
+                parent,
+                foreign_symbol,
+                arguments,
+                ret_layout,
+                ForeignCallOrInvoke::Call,
+            )
+        }
     }
 }
 
 pub fn build_exp_expr<'a, 'ctx, 'env>(
     env: &Env<'a, 'ctx, 'env>,
     layout_ids: &mut LayoutIds<'a>,
-    scope: &Scope<'a, 'ctx>,
+    scope: &mut Scope<'a, 'ctx>,
     parent: FunctionValue<'ctx>,
     layout: &Layout<'a>,
     expr: &roc_mono::ir::Expr<'a>,
@@ -1848,8 +1861,6 @@ fn invoke_roc_function<'a, 'ctx, 'env>(
     {
         env.builder.position_at_end(pass_block);
 
-        // env.builder.build_store(alloca, call_result);
-        // scope.insert(symbol, (layout, alloca));
         scope.insert(symbol, (layout, call_result));
 
         build_exp_stmt(env, layout_ids, scope, parent, pass);
@@ -1909,7 +1920,7 @@ pub fn build_exp_stmt<'a, 'ctx, 'env>(
             for (symbol, expr, layout) in queue {
                 debug_assert!(layout != &Layout::RecursivePointer);
 
-                let val = build_exp_expr(env, layout_ids, &scope, parent, layout, &expr);
+                let val = build_exp_expr(env, layout_ids, scope, parent, layout, &expr);
 
                 // Make a new scope which includes the binding we just encountered.
                 // This should be done *after* compiling the bound expr, since any
@@ -2012,7 +2023,20 @@ pub fn build_exp_stmt<'a, 'ctx, 'env>(
             CallType::Foreign {
                 ref foreign_symbol,
                 ref ret_layout,
-            } => build_foreign_symbol(env, scope, foreign_symbol, call.arguments, ret_layout),
+            } => build_foreign_symbol(
+                env,
+                layout_ids,
+                scope,
+                parent,
+                foreign_symbol,
+                call.arguments,
+                ret_layout,
+                ForeignCallOrInvoke::Invoke {
+                    symbol: *symbol,
+                    pass,
+                    fail,
+                },
+            ),
 
             CallType::LowLevel { .. } => {
                 unreachable!("lowlevel itself never throws exceptions")
@@ -2116,12 +2140,6 @@ pub fn build_exp_stmt<'a, 'ctx, 'env>(
             context.i64_type().const_zero().into()
         }
 
-        /*
-        Inc(symbol1, 1, Dec(symbol2, cont)) if symbol1 == symbol2 => {
-            dbg!(symbol1);
-            build_exp_stmt(env, layout_ids, scope, parent, cont)
-        }
-        */
         Refcounting(modify, cont) => {
             use ModifyRc::*;
 
@@ -4008,70 +4026,159 @@ fn run_low_level<'a, 'ctx, 'env>(
     }
 }
 
+enum ForeignCallOrInvoke<'a> {
+    Call,
+    Invoke {
+        symbol: Symbol,
+        pass: &'a roc_mono::ir::Stmt<'a>,
+        fail: &'a roc_mono::ir::Stmt<'a>,
+    },
+}
+
+fn build_foreign_symbol_return_result<'a, 'ctx, 'env>(
+    env: &Env<'a, 'ctx, 'env>,
+    scope: &mut Scope<'a, 'ctx>,
+    foreign: &roc_module::ident::ForeignSymbol,
+    arguments: &[Symbol],
+    return_type: BasicTypeEnum<'ctx>,
+) -> (FunctionValue<'ctx>, &'a [BasicValueEnum<'ctx>]) {
+    let mut arg_vals: Vec<BasicValueEnum> = Vec::with_capacity_in(arguments.len(), env.arena);
+    let mut arg_types = Vec::with_capacity_in(arguments.len() + 1, env.arena);
+
+    for arg in arguments.iter() {
+        let (value, layout) = load_symbol_and_layout(scope, arg);
+        arg_vals.push(value);
+        let arg_type = basic_type_from_layout(env.arena, env.context, layout, env.ptr_bytes);
+        debug_assert_eq!(arg_type, value.get_type());
+        arg_types.push(arg_type);
+    }
+
+    let function_type = get_fn_type(&return_type, &arg_types);
+    let function = get_foreign_symbol(env, foreign.clone(), function_type);
+
+    (function, arg_vals.into_bump_slice())
+}
+
+fn build_foreign_symbol_write_result_into_ptr<'a, 'ctx, 'env>(
+    env: &Env<'a, 'ctx, 'env>,
+    scope: &mut Scope<'a, 'ctx>,
+    foreign: &roc_module::ident::ForeignSymbol,
+    arguments: &[Symbol],
+    return_pointer: PointerValue<'ctx>,
+) -> (FunctionValue<'ctx>, &'a [BasicValueEnum<'ctx>]) {
+    let mut arg_vals: Vec<BasicValueEnum> = Vec::with_capacity_in(arguments.len(), env.arena);
+    let mut arg_types = Vec::with_capacity_in(arguments.len() + 1, env.arena);
+
+    arg_vals.push(return_pointer.into());
+    arg_types.push(return_pointer.get_type().into());
+
+    for arg in arguments.iter() {
+        let (value, layout) = load_symbol_and_layout(scope, arg);
+        arg_vals.push(value);
+        let arg_type = basic_type_from_layout(env.arena, env.context, layout, env.ptr_bytes);
+        debug_assert_eq!(arg_type, value.get_type());
+        arg_types.push(arg_type);
+    }
+
+    let function_type = env.context.void_type().fn_type(&arg_types, false);
+    let function = get_foreign_symbol(env, foreign.clone(), function_type);
+
+    (function, arg_vals.into_bump_slice())
+}
+
+#[allow(clippy::too_many_arguments)]
 fn build_foreign_symbol<'a, 'ctx, 'env>(
     env: &Env<'a, 'ctx, 'env>,
-    scope: &Scope<'a, 'ctx>,
+    layout_ids: &mut LayoutIds<'a>,
+    scope: &mut Scope<'a, 'ctx>,
+    parent: FunctionValue<'ctx>,
     foreign: &roc_module::ident::ForeignSymbol,
     arguments: &[Symbol],
     ret_layout: &Layout<'a>,
+    call_or_invoke: ForeignCallOrInvoke<'a>,
 ) -> BasicValueEnum<'ctx> {
-    let mut arg_vals: Vec<BasicValueEnum> = Vec::with_capacity_in(arguments.len(), env.arena);
-
-    let mut arg_types = Vec::with_capacity_in(arguments.len() + 1, env.arena);
+    let ret_type = basic_type_from_layout(env.arena, env.context, ret_layout, env.ptr_bytes);
+    let return_pointer = env.builder.build_alloca(ret_type, "return_value");
 
     // crude approximation of the C calling convention
     let pass_result_by_pointer = ret_layout.stack_size(env.ptr_bytes) > 2 * env.ptr_bytes;
 
-    if pass_result_by_pointer {
-        // the return value is too big to pass through a register, so the caller must
-        // allocate space for it on its stack, and provide a pointer to write the result into
-        let ret_type = basic_type_from_layout(env.arena, env.context, ret_layout, env.ptr_bytes);
-
-        let ret_ptr_type = get_ptr_type(&ret_type, AddressSpace::Generic);
-
-        let ret_ptr = env.builder.build_alloca(ret_type, "return_value");
-
-        arg_vals.push(ret_ptr.into());
-        arg_types.push(ret_ptr_type.into());
-
-        for arg in arguments.iter() {
-            let (value, layout) = load_symbol_and_layout(scope, arg);
-            arg_vals.push(value);
-            let arg_type = basic_type_from_layout(env.arena, env.context, layout, env.ptr_bytes);
-            arg_types.push(arg_type);
-        }
-
-        let function_type = env.context.void_type().fn_type(&arg_types, false);
-        let function = get_foreign_symbol(env, foreign.clone(), function_type);
-
-        let call = env.builder.build_call(function, arg_vals.as_slice(), "tmp");
-
-        // this is a foreign function, use c calling convention
-        call.set_call_convention(C_CALL_CONV);
-
-        call.try_as_basic_value();
-
-        env.builder.build_load(ret_ptr, "read_result")
+    let (function, arguments) = if pass_result_by_pointer {
+        build_foreign_symbol_write_result_into_ptr(env, scope, foreign, arguments, return_pointer)
     } else {
-        for arg in arguments.iter() {
-            let (value, layout) = load_symbol_and_layout(scope, arg);
-            arg_vals.push(value);
-            let arg_type = basic_type_from_layout(env.arena, env.context, layout, env.ptr_bytes);
-            arg_types.push(arg_type);
+        build_foreign_symbol_return_result(env, scope, foreign, arguments, ret_type)
+    };
+
+    match call_or_invoke {
+        ForeignCallOrInvoke::Call => {
+            let call = env.builder.build_call(function, arguments, "tmp");
+
+            // this is a foreign function, use c calling convention
+            call.set_call_convention(C_CALL_CONV);
+
+            call.try_as_basic_value();
+
+            if pass_result_by_pointer {
+                env.builder.build_load(return_pointer, "read_result")
+            } else {
+                call.try_as_basic_value().left().unwrap()
+            }
         }
+        ForeignCallOrInvoke::Invoke { symbol, pass, fail } => {
+            let pass_block = env.context.append_basic_block(parent, "invoke_pass");
+            let fail_block = env.context.append_basic_block(parent, "invoke_fail");
 
-        let ret_type = basic_type_from_layout(env.arena, env.context, ret_layout, env.ptr_bytes);
-        let function_type = get_fn_type(&ret_type, &arg_types);
-        let function = get_foreign_symbol(env, foreign.clone(), function_type);
+            let call = env
+                .builder
+                .build_invoke(function, arguments, pass_block, fail_block, "tmp");
 
-        let call = env.builder.build_call(function, arg_vals.as_slice(), "tmp");
+            // this is a foreign function, use c calling convention
+            call.set_call_convention(C_CALL_CONV);
 
-        // this is a foreign function, use c calling convention
-        call.set_call_convention(C_CALL_CONV);
+            call.try_as_basic_value();
 
-        call.try_as_basic_value()
-            .left()
-            .unwrap_or_else(|| panic!("LLVM error: Invalid call by pointer."))
+            let call_result = if pass_result_by_pointer {
+                env.builder.build_load(return_pointer, "read_result")
+            } else {
+                call.try_as_basic_value().left().unwrap()
+            };
+
+            {
+                env.builder.position_at_end(pass_block);
+
+                scope.insert(symbol, (ret_layout.clone(), call_result));
+
+                build_exp_stmt(env, layout_ids, scope, parent, pass);
+
+                scope.remove(&symbol);
+            }
+
+            {
+                env.builder.position_at_end(fail_block);
+
+                let landing_pad_type = {
+                    let exception_ptr =
+                        env.context.i8_type().ptr_type(AddressSpace::Generic).into();
+                    let selector_value = env.context.i32_type().into();
+
+                    env.context
+                        .struct_type(&[exception_ptr, selector_value], false)
+                };
+
+                env.builder
+                    .build_catch_all_landing_pad(
+                        &landing_pad_type,
+                        &BasicValueEnum::IntValue(env.context.i8_type().const_zero()),
+                        env.context.i8_type().ptr_type(AddressSpace::Generic),
+                        "invoke_landing_pad",
+                    )
+                    .into_struct_value();
+
+                build_exp_stmt(env, layout_ids, scope, parent, fail);
+            }
+
+            call_result
+        }
     }
 }
 
diff --git a/compiler/gen/src/llvm/build_list.rs b/compiler/gen/src/llvm/build_list.rs
index 7ccbcffbd5..48e7e6797f 100644
--- a/compiler/gen/src/llvm/build_list.rs
+++ b/compiler/gen/src/llvm/build_list.rs
@@ -3,7 +3,10 @@ use crate::llvm::build::{
 };
 use crate::llvm::compare::generic_eq;
 use crate::llvm::convert::{basic_type_from_layout, collection, get_ptr_type};
-use crate::llvm::refcounting::{decrement_refcount_layout, increment_refcount_layout};
+use crate::llvm::refcounting::{
+    decrement_refcount_layout, increment_refcount_layout, refcount_is_one_comparison,
+    PointerToRefcount,
+};
 use inkwell::builder::Builder;
 use inkwell::context::Context;
 use inkwell::types::{BasicTypeEnum, PointerType};
@@ -685,13 +688,38 @@ pub fn list_set<'a, 'ctx, 'env>(
                 original_wrapper,
                 load_list_ptr(builder, original_wrapper, ptr_type),
             ),
-            InPlace::Clone => clone_nonempty_list(
-                env,
-                output_inplace,
-                list_len,
-                load_list_ptr(builder, original_wrapper, ptr_type),
-                elem_layout,
-            ),
+            InPlace::Clone => {
+                let list_ptr = load_list_ptr(builder, original_wrapper, ptr_type);
+
+                let refcount_ptr = PointerToRefcount::from_ptr_to_data(env, list_ptr);
+                let refcount = refcount_ptr.get_refcount(env);
+
+                let rc_is_one = refcount_is_one_comparison(env, refcount);
+
+                let source_block = env.builder.get_insert_block().unwrap();
+                let clone_block = ctx.append_basic_block(parent, "clone");
+                let done_block = ctx.append_basic_block(parent, "done");
+
+                env.builder
+                    .build_conditional_branch(rc_is_one, done_block, clone_block);
+
+                env.builder.position_at_end(clone_block);
+
+                let cloned =
+                    clone_nonempty_list(env, output_inplace, list_len, list_ptr, elem_layout).0;
+
+                env.builder.build_unconditional_branch(done_block);
+
+                env.builder.position_at_end(done_block);
+
+                let list_type = original_wrapper.get_type();
+                let merged = env.builder.build_phi(list_type, "writable_list");
+                merged.add_incoming(&[(&original_wrapper, source_block), (&cloned, clone_block)]);
+
+                let result = merged.as_basic_value().into_struct_value();
+
+                (result, load_list_ptr(builder, result, ptr_type))
+            }
         };
 
         // If we got here, we passed the bounds check, so this is an in-bounds GEP
diff --git a/compiler/gen/src/llvm/refcounting.rs b/compiler/gen/src/llvm/refcounting.rs
index 8fd78f06f2..a7d07c3ca1 100644
--- a/compiler/gen/src/llvm/refcounting.rs
+++ b/compiler/gen/src/llvm/refcounting.rs
@@ -489,7 +489,7 @@ fn modify_refcount_layout<'a, 'ctx, 'env>(
 
                 let field_ptr = env
                     .builder
-                    .build_extract_value(wrapper_struct, 1, "increment_closure_data")
+                    .build_extract_value(wrapper_struct, 1, "modify_rc_closure_data")
                     .unwrap();
 
                 modify_refcount_layout(
diff --git a/compiler/mono/src/borrow.rs b/compiler/mono/src/borrow.rs
index 905ba01253..14f6687ed0 100644
--- a/compiler/mono/src/borrow.rs
+++ b/compiler/mono/src/borrow.rs
@@ -261,6 +261,16 @@ impl<'a> BorrowInfState<'a> {
         }
     }
 
+    fn own_arg(&mut self, x: Symbol) {
+        self.own_var(x);
+    }
+
+    fn own_args(&mut self, xs: &[Symbol]) {
+        for x in xs.iter() {
+            self.own_arg(*x);
+        }
+    }
+
     /// For each xs[i], if xs[i] is owned, then mark ps[i] as owned.
     /// We use this action to preserve tail calls. That is, if we have
     /// a tail call `f xs`, if the i-th parameter is borrowed, but `xs[i]` is owned
@@ -308,31 +318,33 @@ impl<'a> BorrowInfState<'a> {
         } = e;
 
         match call_type {
-            ByName {
-                name, arg_layouts, ..
-            }
-            | ByPointer {
-                name, arg_layouts, ..
-            } => {
+            ByName { name, .. } => {
                 // get the borrow signature of the applied function
-                let ps = match self.param_map.get_symbol(*name) {
-                    Some(slice) => slice,
-                    None => Vec::from_iter_in(
-                        arg_layouts.iter().cloned().map(|layout| Param {
-                            symbol: Symbol::UNDERSCORE,
-                            borrow: false,
-                            layout,
-                        }),
-                        self.arena,
-                    )
-                    .into_bump_slice(),
-                };
+                match self.param_map.get_symbol(*name) {
+                    Some(ps) => {
+                        // the return value will be owned
+                        self.own_var(z);
 
+                        // if the function exects an owned argument (ps), the argument must be owned (args)
+                        self.own_args_using_params(arguments, ps);
+                    }
+                    None => {
+                        // this is really an indirect call, but the function was bound to a symbol
+                        // the return value will be owned
+                        self.own_var(z);
+
+                        // if the function exects an owned argument (ps), the argument must be owned (args)
+                        self.own_args(arguments);
+                    }
+                }
+            }
+
+            ByPointer { .. } => {
                 // the return value will be owned
                 self.own_var(z);
 
                 // if the function exects an owned argument (ps), the argument must be owned (args)
-                self.own_args_using_params(arguments, ps);
+                self.own_args(arguments);
             }
 
             LowLevel { op } => {
diff --git a/compiler/mono/src/inc_dec.rs b/compiler/mono/src/inc_dec.rs
index c8fb776ac9..a7413a9c60 100644
--- a/compiler/mono/src/inc_dec.rs
+++ b/compiler/mono/src/inc_dec.rs
@@ -466,35 +466,46 @@ impl<'a> Context<'a> {
                 &*self.arena.alloc(Stmt::Let(z, v, l, b))
             }
 
-            ByName {
-                name, arg_layouts, ..
-            }
-            | ByPointer {
-                name, arg_layouts, ..
-            } => {
+            ByName { name, .. } => {
                 // get the borrow signature
-                let ps = match self.param_map.get_symbol(*name) {
-                    Some(slice) => slice,
-                    None => Vec::from_iter_in(
-                        arg_layouts.iter().cloned().map(|layout| Param {
-                            symbol: Symbol::UNDERSCORE,
-                            borrow: false,
-                            layout,
-                        }),
-                        self.arena,
-                    )
-                    .into_bump_slice(),
-                };
+                match self.param_map.get_symbol(*name) {
+                    Some(ps) => {
+                        let v = Expr::Call(crate::ir::Call {
+                            call_type,
+                            arguments,
+                        });
 
+                        let b = self.add_dec_after_application(arguments, ps, b, b_live_vars);
+                        let b = self.arena.alloc(Stmt::Let(z, v, l, b));
+
+                        self.add_inc_before(arguments, ps, b, b_live_vars)
+                    }
+                    None => {
+                        // an indirect call that was bound to a name
+                        let v = Expr::Call(crate::ir::Call {
+                            call_type,
+                            arguments,
+                        });
+
+                        self.add_inc_before_consume_all(
+                            arguments,
+                            self.arena.alloc(Stmt::Let(z, v, l, b)),
+                            b_live_vars,
+                        )
+                    }
+                }
+            }
+            ByPointer { .. } => {
                 let v = Expr::Call(crate::ir::Call {
                     call_type,
                     arguments,
                 });
 
-                let b = self.add_dec_after_application(arguments, ps, b, b_live_vars);
-                let b = self.arena.alloc(Stmt::Let(z, v, l, b));
-
-                self.add_inc_before(arguments, ps, b, b_live_vars)
+                self.add_inc_before_consume_all(
+                    arguments,
+                    self.arena.alloc(Stmt::Let(z, v, l, b)),
+                    b_live_vars,
+                )
             }
         }
     }
diff --git a/compiler/parse/src/blankspace.rs b/compiler/parse/src/blankspace.rs
index 9b422a9df6..d3f0b70f55 100644
--- a/compiler/parse/src/blankspace.rs
+++ b/compiler/parse/src/blankspace.rs
@@ -444,6 +444,9 @@ where
         let mut state = state;
         let mut any_newlines = false;
 
+        let start_row = original_state.line;
+        let start_col = original_state.column;
+
         let start_bytes_len = state.bytes.len();
 
         while !state.bytes.is_empty() {
@@ -491,7 +494,13 @@ where
                                     let progress =
                                         Progress::from_lengths(start_bytes_len, state.bytes.len());
                                     state = state
-                                        .check_indent_e(arena, min_indent, indent_problem)
+                                        .check_indent_e(
+                                            arena,
+                                            min_indent,
+                                            indent_problem,
+                                            start_row,
+                                            start_col,
+                                        )
                                         .map_err(|(fail, _)| {
                                             (progress, fail, original_state.clone())
                                         })?
@@ -523,7 +532,13 @@ where
                                         );
                                         if any_newlines {
                                             state = state
-                                                .check_indent_e(arena, min_indent, indent_problem)
+                                                .check_indent_e(
+                                                    arena,
+                                                    min_indent,
+                                                    indent_problem,
+                                                    start_row,
+                                                    start_col,
+                                                )
                                                 .map_err(|(fail, _)| {
                                                     (progress, fail, original_state.clone())
                                                 })?;
@@ -692,7 +707,13 @@ where
                                 progress,
                                 space_slice,
                                 state
-                                    .check_indent_e(arena, min_indent, indent_problem)
+                                    .check_indent_e(
+                                        arena,
+                                        min_indent,
+                                        indent_problem,
+                                        start_row,
+                                        start_col,
+                                    )
                                     .map_err(|(fail, _)| (progress, fail, original_state))?,
                             ));
                         }
@@ -720,7 +741,7 @@ where
             let progress = Progress::from_lengths(start_bytes_len, state.bytes.len());
             if any_newlines {
                 state = state
-                    .check_indent_e(arena, min_indent, indent_problem)
+                    .check_indent_e(arena, min_indent, indent_problem, start_row, start_col)
                     .map_err(|(fail, _)| (progress, fail, original_state))?;
             }
 
diff --git a/compiler/parse/src/parser.rs b/compiler/parse/src/parser.rs
index f96d521ebe..3cce208d30 100644
--- a/compiler/parse/src/parser.rs
+++ b/compiler/parse/src/parser.rs
@@ -72,12 +72,14 @@ impl<'a> State<'a> {
         _arena: &'a Bump,
         min_indent: u16,
         to_error: TE,
+        row: Row,
+        col: Col,
     ) -> Result<Self, (E, Self)>
     where
         TE: Fn(Row, Col) -> E,
     {
         if self.indent_col < min_indent {
-            Err((to_error(self.line, self.column), self))
+            Err((to_error(row, col), self))
         } else {
             Ok(self)
         }
@@ -370,29 +372,33 @@ pub type Col = u16;
 pub enum Type<'a> {
     TRecord(TRecord<'a>, Row, Col),
     TTagUnion(TTagUnion<'a>, Row, Col),
+    TInParens(TInParens<'a>, Row, Col),
+    TApply(TApply, Row, Col),
+    TVariable(TVariable, Row, Col),
+    TWildcard(Row, Col),
     ///
     TStart(Row, Col),
-    TSpace(Row, Col),
+    TEnd(Row, Col),
+    TSpace(BadInputError, Row, Col),
+    TFunctionArgument(Row, Col),
     ///
     TIndentStart(Row, Col),
+    TIndentEnd(Row, Col),
+    TAsIndentStart(Row, Col),
 }
 
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub enum TRecord<'a> {
     End(Row, Col),
     Open(Row, Col),
-    ///
+
     Field(Row, Col),
     Colon(Row, Col),
     Optional(Row, Col),
     Type(&'a Type<'a>, Row, Col),
 
-    // TODO REMOVE in favor of Type
-    Syntax(&'a SyntaxError<'a>, Row, Col),
-
-    ///
     Space(BadInputError, Row, Col),
-    ///
+
     IndentOpen(Row, Col),
     IndentColon(Row, Col),
     IndentOptional(Row, Col),
@@ -403,11 +409,21 @@ pub enum TRecord<'a> {
 pub enum TTagUnion<'a> {
     End(Row, Col),
     Open(Row, Col),
-    ///
+
     Type(&'a Type<'a>, Row, Col),
 
-    // TODO REMOVE in favor of Type
-    Syntax(&'a SyntaxError<'a>, Row, Col),
+    Space(BadInputError, Row, Col),
+
+    IndentOpen(Row, Col),
+    IndentEnd(Row, Col),
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum TInParens<'a> {
+    End(Row, Col),
+    Open(Row, Col),
+    ///
+    Type(&'a Type<'a>, Row, Col),
 
     ///
     Space(BadInputError, Row, Col),
@@ -416,6 +432,26 @@ pub enum TTagUnion<'a> {
     IndentEnd(Row, Col),
 }
 
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum TApply {
+    ///
+    StartNotUppercase(Row, Col),
+    End(Row, Col),
+    Space(BadInputError, Row, Col),
+    ///
+    DoubleDot(Row, Col),
+    TrailingDot(Row, Col),
+    StartIsNumber(Row, Col),
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum TVariable {
+    ///
+    StartNotLowercase(Row, Col),
+    End(Row, Col),
+    Space(BadInputError, Row, Col),
+}
+
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub enum ContextStack<'a> {
     Cons(ContextItem, &'a ContextStack<'a>),
@@ -529,6 +565,26 @@ where
     }
 }
 
+pub fn not_e<'a, P, TE, E, X, Val>(parser: P, to_error: TE) -> impl Parser<'a, (), E>
+where
+    TE: Fn(Row, Col) -> E,
+    P: Parser<'a, Val, X>,
+    E: 'a,
+{
+    move |arena, state: State<'a>| {
+        let original_state = state.clone();
+
+        match parser.parse(arena, state) {
+            Ok((_, _, _)) => Err((
+                NoProgress,
+                to_error(original_state.line, original_state.column),
+                original_state,
+            )),
+            Err((_, _, _)) => Ok((NoProgress, (), original_state)),
+        }
+    }
+}
+
 pub fn lookahead<'a, Peek, P, PeekVal, Val, Error>(
     peek: Peek,
     parser: P,
@@ -758,6 +814,27 @@ pub fn peek_utf8_char<'a>(state: &State) -> Result<(char, usize), SyntaxError<'a
     }
 }
 
+/// A single UTF-8-encoded char. This will both parse *and* validate that the
+/// char is valid UTF-8, but it will *not* advance the state.
+pub fn peek_utf8_char_e<EOF, TE, E>(
+    state: &State,
+    end_of_file: EOF,
+    to_error: TE,
+) -> Result<(char, usize), E>
+where
+    TE: Fn(BadInputError, Row, Col) -> E,
+    EOF: Fn(Row, Col) -> E,
+{
+    if !state.bytes.is_empty() {
+        match char::from_utf8_slice_start(state.bytes) {
+            Ok((ch, len_utf8)) => Ok((ch, len_utf8)),
+            Err(_) => Err(to_error(BadInputError::BadUtf8, state.line, state.column)),
+        }
+    } else {
+        Err(end_of_file(state.line, state.column))
+    }
+}
+
 /// A single UTF-8-encoded char, with an offset. This will both parse *and*
 /// validate that the char is valid UTF-8, but it will *not* advance the state.
 pub fn peek_utf8_char_at<'a>(
@@ -778,7 +855,10 @@ pub fn peek_utf8_char_at<'a>(
     }
 }
 
-pub fn keyword<'a>(keyword: &'static str, min_indent: u16) -> impl Parser<'a, (), SyntaxError<'a>> {
+pub fn keyword<'a>(
+    keyword: &'static str,
+    _min_indent: u16,
+) -> impl Parser<'a, (), SyntaxError<'a>> {
     move |arena, state: State<'a>| {
         let initial_state = state.clone();
         // first parse the keyword characters
@@ -786,18 +866,47 @@ pub fn keyword<'a>(keyword: &'static str, min_indent: u16) -> impl Parser<'a, ()
 
         // then we must have at least one space character
         // TODO this is potentially wasteful if there are a lot of spaces
-        match crate::blankspace::space1(min_indent).parse(arena, after_keyword_state.clone()) {
-            Err((_, fail, _)) => {
-                // this is not a keyword, maybe it's `whence` or `iffy`
-                // anyway, make no progress and return the initial state
-                // so we can try something else
-                Err((NoProgress, fail, initial_state))
-            }
-            Ok((_, _, _)) => {
+        match peek_utf8_char(&after_keyword_state) {
+            Ok((next, _width)) if next == ' ' || next == '#' || next == '\n' => {
                 // give back the state after parsing the keyword, but before the whitespace
                 // that way we can attach the whitespace to whatever follows
                 Ok((MadeProgress, (), after_keyword_state))
             }
+            _ => {
+                // this is not a keyword, maybe it's `whence` or `iffy`
+                // anyway, make no progress and return the initial state
+                // so we can try something else
+                Err((NoProgress, SyntaxError::ConditionFailed, initial_state))
+            }
+        }
+    }
+}
+
+pub fn keyword_e<'a, E>(keyword: &'static str, if_error: E) -> impl Parser<'a, (), E>
+where
+    E: 'a + Clone,
+{
+    move |arena, state: State<'a>| {
+        let initial_state = state.clone();
+        // first parse the keyword characters
+        let (_, _, after_keyword_state) = ascii_string(keyword)
+            .parse(arena, state)
+            .map_err(|(_, _, state)| (NoProgress, if_error.clone(), state))?;
+
+        // then we must have at least one space character
+        // TODO this is potentially wasteful if there are a lot of spaces
+        match peek_utf8_char(&after_keyword_state) {
+            Ok((next, _width)) if next == ' ' || next == '#' || next == '\n' => {
+                // give back the state after parsing the keyword, but before the whitespace
+                // that way we can attach the whitespace to whatever follows
+                Ok((MadeProgress, (), after_keyword_state))
+            }
+            _ => {
+                // this is not a keyword, maybe it's `whence` or `iffy`
+                // anyway, make no progress and return the initial state
+                // so we can try something else
+                Err((NoProgress, if_error.clone(), initial_state))
+            }
         }
     }
 }
@@ -815,20 +924,15 @@ pub fn ascii_string<'a>(keyword: &'static str) -> impl Parser<'a, (), SyntaxErro
         let len = keyword.len();
 
         // TODO do this comparison in one SIMD instruction (on supported systems)
-        match state.bytes.get(0..len) {
-            Some(next_str) => {
-                if next_str == keyword.as_bytes() {
-                    Ok((
-                        Progress::MadeProgress,
-                        (),
-                        state.advance_without_indenting(arena, len)?,
-                    ))
-                } else {
-                    let (_, fail, state) = unexpected(arena, len, Attempting::Keyword, state);
-                    Err((NoProgress, fail, state))
-                }
-            }
-            _ => Err(unexpected_eof(arena, state, 0)),
+        if state.bytes.starts_with(keyword.as_bytes()) {
+            Ok((
+                Progress::MadeProgress,
+                (),
+                state.advance_without_indenting(arena, len)?,
+            ))
+        } else {
+            let (_, fail, state) = unexpected(arena, len, Attempting::Keyword, state);
+            Err((NoProgress, fail, state))
         }
     }
 }
@@ -1357,6 +1461,58 @@ where
     }
 }
 
+pub fn word2<'a, ToError, E>(word_1: u8, word_2: u8, to_error: ToError) -> impl Parser<'a, (), E>
+where
+    ToError: Fn(Row, Col) -> E,
+    E: 'a,
+{
+    debug_assert_ne!(word_1, b'\n');
+    debug_assert_ne!(word_2, b'\n');
+
+    let needle = [word_1, word_2];
+
+    move |_arena: &'a Bump, state: State<'a>| {
+        if state.bytes.starts_with(&needle) {
+            Ok((
+                MadeProgress,
+                (),
+                State {
+                    bytes: &state.bytes[2..],
+                    column: state.column + 2,
+                    ..state
+                },
+            ))
+        } else {
+            Err((NoProgress, to_error(state.line, state.column), state))
+        }
+    }
+}
+
+pub fn check_indent<'a, TE, E>(min_indent: u16, to_problem: TE) -> impl Parser<'a, (), E>
+where
+    TE: Fn(Row, Col) -> E,
+    E: 'a,
+{
+    move |_arena, state: State<'a>| {
+        dbg!(state.indent_col, min_indent);
+        if state.indent_col < min_indent {
+            Err((NoProgress, to_problem(state.line, state.column), state))
+        } else {
+            Ok((NoProgress, (), state))
+        }
+    }
+}
+
+#[macro_export]
+macro_rules! word1_check_indent {
+    ($word:expr, $word_problem:expr, $min_indent:expr, $indent_problem:expr) => {
+        and!(
+            word1($word, $word_problem),
+            crate::parser::check_indent($min_indent, $indent_problem)
+        )
+    };
+}
+
 #[allow(dead_code)]
 fn in_context<'a, AddContext, P1, P2, Start, A, X, Y>(
     add_context: AddContext,
diff --git a/compiler/parse/src/type_annotation.rs b/compiler/parse/src/type_annotation.rs
index 652ec7f3a1..6ee9b87b0b 100644
--- a/compiler/parse/src/type_annotation.rs
+++ b/compiler/parse/src/type_annotation.rs
@@ -1,36 +1,26 @@
-use crate::ast::{AssignedField, Attempting, CommentOrNewline, Tag, TypeAnnotation};
-use crate::blankspace::{space0_around, space0_before, space1, space1_before};
-use crate::expr::{global_tag, private_tag};
+use crate::ast::{AssignedField, Tag, TypeAnnotation};
+use crate::blankspace::{space0_around_e, space0_before_e, space0_e};
 use crate::ident::join_module_parts;
 use crate::keyword;
 use crate::parser::{
-    allocated, ascii_char, ascii_string, not, optional, peek_utf8_char, specialize, specialize_ref,
-    unexpected, word1, BadInputError, Either, ParseResult, Parser,
+    allocated, backtrackable, not_e, optional, peek_utf8_char_e, specialize, specialize_ref, word1,
+    word2, BadInputError, ParseResult, Parser,
     Progress::{self, *},
-    State, SyntaxError, TRecord, TTagUnion, Type,
+    State, SyntaxError, TApply, TInParens, TRecord, TTagUnion, TVariable, Type,
 };
 use bumpalo::collections::string::String;
 use bumpalo::collections::vec::Vec;
 use bumpalo::Bump;
-use roc_collections::all::arena_join;
 use roc_region::all::{Located, Region};
 
 pub fn located<'a>(
     min_indent: u16,
 ) -> impl Parser<'a, Located<TypeAnnotation<'a>>, SyntaxError<'a>> {
-    expression(min_indent)
+    specialize(|x, _, _| SyntaxError::Type(x), expression(min_indent))
 }
 
 #[inline(always)]
-fn tag_union_type<'a>(min_indent: u16) -> impl Parser<'a, TypeAnnotation<'a>, SyntaxError<'a>> {
-    let f = |x, row, col| SyntaxError::Type(Type::TTagUnion(x, row, col));
-    specialize(f, tag_union_type_internal(min_indent))
-}
-
-#[inline(always)]
-fn tag_union_type_internal<'a>(
-    min_indent: u16,
-) -> impl Parser<'a, TypeAnnotation<'a>, TTagUnion<'a>> {
+fn tag_union_type<'a>(min_indent: u16) -> impl Parser<'a, TypeAnnotation<'a>, TTagUnion<'a>> {
     move |arena, state| {
         let (_, (tags, final_comments), state) = collection_trailing_sep_e!(
             word1(b'[', TTagUnion::Open),
@@ -45,11 +35,9 @@ fn tag_union_type_internal<'a>(
         .parse(arena, state)?;
 
         // This could be an open tag union, e.g. `[ Foo, Bar ]a`
-        let (_, ext, state) = optional(allocated(specialize_ref(
-            TTagUnion::Syntax,
-            term(min_indent),
-        )))
-        .parse(arena, state)?;
+        let (_, ext, state) =
+            optional(allocated(specialize_ref(TTagUnion::Type, term(min_indent))))
+                .parse(arena, state)?;
 
         let result = TypeAnnotation::TagUnion {
             tags: tags.into_bump_slice(),
@@ -61,36 +49,41 @@ fn tag_union_type_internal<'a>(
     }
 }
 
-#[allow(clippy::type_complexity)]
-pub fn term<'a>(min_indent: u16) -> impl Parser<'a, Located<TypeAnnotation<'a>>, SyntaxError<'a>> {
+fn term<'a>(min_indent: u16) -> impl Parser<'a, Located<TypeAnnotation<'a>>, Type<'a>> {
     map_with_arena!(
         and!(
             one_of!(
                 loc_wildcard(),
-                loc_parenthetical_type(min_indent),
-                loc!(record_type(min_indent)),
-                loc!(tag_union_type(min_indent)),
+                specialize(Type::TInParens, loc_type_in_parens(min_indent)),
+                loc!(specialize(Type::TRecord, record_type(min_indent))),
+                loc!(specialize(Type::TTagUnion, tag_union_type(min_indent))),
                 loc!(applied_type(min_indent)),
-                loc!(parse_type_variable)
+                loc!(specialize(Type::TVariable, parse_type_variable))
             ),
-            |a, s| {
-                optional(
-                    // Inline type annotation, e.g. [ Nil, Cons a (List a) ] as List a
+            // Inline alias notation, e.g. [ Nil, Cons a (List a) ] as List a
+            one_of![
+                map!(
                     and!(
-                        space1(min_indent),
-                        skip_first!(
-                            crate::parser::keyword(keyword::AS, min_indent),
-                            space1_before(term(min_indent), min_indent)
+                        skip_second!(
+                            backtrackable(space0_e(min_indent, Type::TSpace, Type::TIndentEnd)),
+                            crate::parser::keyword_e(keyword::AS, Type::TEnd(0, 0))
+                        ),
+                        space0_before_e(
+                            term(min_indent),
+                            min_indent,
+                            Type::TSpace,
+                            Type::TAsIndentStart
                         )
                     ),
-                )
-                .parse(a, s)
-            }
+                    Some
+                ),
+                |_, state| Ok((NoProgress, None, state))
+            ]
         ),
         |arena: &'a Bump,
          (loc_ann, opt_as): (
             Located<TypeAnnotation<'a>>,
-            Option<(&'a [CommentOrNewline<'a>], Located<TypeAnnotation<'a>>)>
+            Option<(&'a [_], Located<TypeAnnotation<'a>>)>
         )| {
             match opt_as {
                 Some((spaces, loc_as)) => {
@@ -108,87 +101,195 @@ pub fn term<'a>(min_indent: u16) -> impl Parser<'a, Located<TypeAnnotation<'a>>,
 }
 
 /// The `*` type variable, e.g. in (List *) Wildcard,
-fn loc_wildcard<'a>() -> impl Parser<'a, Located<TypeAnnotation<'a>>, SyntaxError<'a>> {
-    map!(loc!(ascii_char(b'*')), |loc_val: Located<()>| {
+fn loc_wildcard<'a>() -> impl Parser<'a, Located<TypeAnnotation<'a>>, Type<'a>> {
+    map!(loc!(word1(b'*', Type::TWildcard)), |loc_val: Located<()>| {
         loc_val.map(|_| TypeAnnotation::Wildcard)
     })
 }
 
-fn loc_applied_arg<'a>(
-    min_indent: u16,
-) -> impl Parser<'a, Located<TypeAnnotation<'a>>, SyntaxError<'a>> {
-    skip_first!(
-        // Once we hit an "as", stop parsing args
-        // and roll back parsing of preceding spaces
-        not(and!(
-            space1(min_indent),
-            crate::parser::keyword(keyword::AS, min_indent)
-        )),
-        space1_before(
-            one_of!(
-                loc_wildcard(),
-                loc_parenthetical_type(min_indent),
-                loc!(record_type(min_indent)),
-                loc!(tag_union_type(min_indent)),
-                loc!(parse_concrete_type),
-                loc!(parse_type_variable)
-            ),
-            min_indent
-        )
+fn loc_applied_arg<'a>(min_indent: u16) -> impl Parser<'a, Located<TypeAnnotation<'a>>, Type<'a>> {
+    use crate::ast::Spaceable;
+
+    map_with_arena!(
+        and!(
+            backtrackable(space0_e(min_indent, Type::TSpace, Type::TIndentStart)),
+            skip_first!(
+                // Once we hit an "as", stop parsing args
+                // and roll back parsing of preceding spaces
+                not_e(
+                    crate::parser::keyword(keyword::AS, min_indent),
+                    Type::TStart
+                ),
+                one_of!(
+                    loc_wildcard(),
+                    specialize(Type::TInParens, loc_type_in_parens(min_indent)),
+                    loc!(specialize(Type::TRecord, record_type(min_indent))),
+                    loc!(specialize(Type::TTagUnion, tag_union_type(min_indent))),
+                    loc!(specialize(Type::TApply, parse_concrete_type)),
+                    loc!(specialize(Type::TVariable, parse_type_variable))
+                )
+            )
+        ),
+        |arena: &'a Bump, (spaces, argument): (&'a [_], Located<TypeAnnotation<'a>>)| {
+            if spaces.is_empty() {
+                argument
+            } else {
+                let Located { region, value } = argument;
+                arena.alloc(value).with_spaces_before(spaces, region)
+            }
+        }
     )
 }
 
-fn loc_applied_args<'a>(
+fn loc_type_in_parens<'a>(
     min_indent: u16,
-) -> impl Parser<'a, Vec<'a, Located<TypeAnnotation<'a>>>, SyntaxError<'a>> {
-    zero_or_more!(loc_applied_arg(min_indent))
-}
-
-#[inline(always)]
-fn loc_parenthetical_type<'a>(
-    min_indent: u16,
-) -> impl Parser<'a, Located<TypeAnnotation<'a>>, SyntaxError<'a>> {
+) -> impl Parser<'a, Located<TypeAnnotation<'a>>, TInParens<'a>> {
+    // TODO what if the middle parser returns EOF?
     between!(
-        ascii_char(b'('),
-        space0_around(
-            move |arena, state| expression(min_indent).parse(arena, state),
+        word1(b'(', TInParens::Open),
+        space0_around_e(
+            move |arena, state| specialize_ref(TInParens::Type, expression(min_indent))
+                .parse(arena, state),
             min_indent,
+            TInParens::Space,
+            TInParens::IndentEnd,
         ),
-        ascii_char(b')')
+        word1(b')', TInParens::End)
     )
 }
 
 #[inline(always)]
 fn tag_type<'a>(min_indent: u16) -> impl Parser<'a, Tag<'a>, TTagUnion<'a>> {
     move |arena, state: State<'a>| {
-        let (_, either_name, state) = specialize_ref(
-            TTagUnion::Syntax,
-            either!(loc!(private_tag()), loc!(global_tag())),
-        )
-        .parse(arena, state)?;
+        let (_, name, state) = loc!(parse_tag_name(TTagUnion::End)).parse(arena, state)?;
 
         let (_, args, state) =
-            specialize_ref(TTagUnion::Syntax, loc_applied_args(min_indent)).parse(arena, state)?;
+            specialize_ref(TTagUnion::Type, loc_applied_args_e(min_indent)).parse(arena, state)?;
 
-        let result = match either_name {
-            Either::First(name) => Tag::Private {
+        let result = if name.value.starts_with('@') {
+            Tag::Private {
                 name,
                 args: args.into_bump_slice(),
-            },
-            Either::Second(name) => Tag::Global {
+            }
+        } else {
+            Tag::Global {
                 name,
                 args: args.into_bump_slice(),
-            },
+            }
         };
 
         Ok((MadeProgress, result, state))
     }
 }
 
+use crate::parser::{Col, Row};
+fn parse_tag_name<'a, F, E>(to_problem: F) -> impl Parser<'a, &'a str, E>
+where
+    F: Fn(Row, Col) -> E,
+    E: 'a,
+{
+    use encode_unicode::CharExt;
+
+    move |arena, mut state: State<'a>| {
+        let mut buf;
+
+        match char::from_utf8_slice_start(state.bytes) {
+            Ok((first_letter, bytes_parsed)) => match first_letter {
+                '@' => {
+                    debug_assert_eq!(bytes_parsed, 1);
+
+                    // parsing a private tag name
+                    match char::from_utf8_slice_start(&state.bytes[1..]) {
+                        Ok((second_letter, bytes_parsed_2)) if second_letter.is_uppercase() => {
+                            let total_parsed = bytes_parsed + bytes_parsed_2;
+
+                            buf = String::with_capacity_in(total_parsed, arena);
+
+                            buf.push('@');
+                            buf.push(second_letter);
+
+                            state = state
+                                .advance_without_indenting(arena, total_parsed)
+                                .map_err(|(progress, _, state)| {
+                                    (progress, to_problem(state.line, state.column), state)
+                                })?;
+                        }
+                        _ => {
+                            // important for error messages
+                            state = state
+                                .advance_without_indenting(arena, bytes_parsed)
+                                .map_err(|(progress, _, state)| {
+                                    (progress, to_problem(state.line, state.column), state)
+                                })?;
+
+                            let row = state.line;
+                            let col = state.column;
+                            return state.fail(arena, MadeProgress, to_problem(row, col));
+                        }
+                    }
+                }
+
+                _ if first_letter.is_uppercase() => {
+                    buf = String::with_capacity_in(1, arena);
+
+                    buf.push(first_letter);
+
+                    state = state
+                        .advance_without_indenting(arena, bytes_parsed)
+                        .map_err(|(progress, _, state)| {
+                            (progress, to_problem(state.line, state.column), state)
+                        })?;
+                }
+
+                _ => {
+                    let row = state.line;
+                    let col = state.column;
+                    return state.fail(arena, NoProgress, to_problem(row, col));
+                }
+            },
+            Err(_) => {
+                let row = state.line;
+                let col = state.column;
+                return state.fail(arena, NoProgress, to_problem(row, col));
+            }
+        };
+
+        while !state.bytes.is_empty() {
+            match char::from_utf8_slice_start(state.bytes) {
+                Ok((ch, bytes_parsed)) => {
+                    // After the first character, only these are allowed:
+                    //
+                    // * Unicode alphabetic chars - you might include `鹏` if that's clear to your readers
+                    // * ASCII digits - e.g. `1` but not `¾`, both of which pass .is_numeric()
+                    // * A ':' indicating the end of the field
+                    if ch.is_alphabetic() || ch.is_ascii_digit() {
+                        buf.push(ch);
+
+                        state = state
+                            .advance_without_indenting(arena, bytes_parsed)
+                            .map_err(|(progress, _, state)| {
+                                (progress, to_problem(state.line, state.column), state)
+                            })?;
+                    } else {
+                        // This is the end of the field. We're done!
+                        break;
+                    }
+                }
+                Err(_) => {
+                    let row = state.line;
+                    let col = state.column;
+                    return state.fail(arena, MadeProgress, to_problem(row, col));
+                }
+            };
+        }
+
+        Ok((MadeProgress, buf.into_bump_str(), state))
+    }
+}
+
 fn record_type_field<'a>(
     min_indent: u16,
 ) -> impl Parser<'a, AssignedField<'a, TypeAnnotation<'a>>, TRecord<'a>> {
-    use crate::blankspace::{space0_before_e, space0_e};
     use crate::ident::lowercase_ident;
     use crate::parser::Either::*;
     use AssignedField::*;
@@ -216,7 +317,7 @@ fn record_type_field<'a>(
         ))
         .parse(arena, state)?;
 
-        let val_parser = specialize_ref(TRecord::Syntax, term(min_indent));
+        let val_parser = specialize_ref(TRecord::Type, term(min_indent));
 
         match opt_loc_val {
             Some(First(_)) => {
@@ -261,25 +362,16 @@ fn record_type_field<'a>(
 }
 
 #[inline(always)]
-fn record_type<'a>(min_indent: u16) -> impl Parser<'a, TypeAnnotation<'a>, SyntaxError<'a>> {
-    let f = |x, row, col| SyntaxError::Type(Type::TRecord(x, row, col));
-    specialize(f, record_type_internal(min_indent))
-}
-
-#[inline(always)]
-fn record_type_internal<'a>(min_indent: u16) -> impl Parser<'a, TypeAnnotation<'a>, TRecord<'a>> {
+fn record_type<'a>(min_indent: u16) -> impl Parser<'a, TypeAnnotation<'a>, TRecord<'a>> {
     use crate::type_annotation::TypeAnnotation::*;
 
-    let field_term = move |a, s| match term(min_indent).parse(a, s) {
-        Ok(t) => Ok(t),
-        Err((p, error, s)) => Err((p, TRecord::Syntax(a.alloc(error), s.line, s.column), s)),
-    };
-
     move |arena, state| {
         let (_, (fields, final_comments), state) = collection_trailing_sep_e!(
+            // word1_check_indent!(b'{', TRecord::Open, min_indent, TRecord::IndentOpen),
             word1(b'{', TRecord::Open),
             loc!(record_type_field(min_indent)),
             word1(b',', TRecord::End),
+            // word1_check_indent!(b'}', TRecord::End, min_indent, TRecord::IndentEnd),
             word1(b'}', TRecord::End),
             min_indent,
             TRecord::Open,
@@ -288,6 +380,7 @@ fn record_type_internal<'a>(min_indent: u16) -> impl Parser<'a, TypeAnnotation<'
         )
         .parse(arena, state)?;
 
+        let field_term = specialize_ref(TRecord::Type, term(min_indent));
         let (_, ext, state) = optional(allocated(field_term)).parse(arena, state)?;
 
         let result = Record {
@@ -300,13 +393,13 @@ fn record_type_internal<'a>(min_indent: u16) -> impl Parser<'a, TypeAnnotation<'
     }
 }
 
-fn applied_type<'a>(min_indent: u16) -> impl Parser<'a, TypeAnnotation<'a>, SyntaxError<'a>> {
+fn applied_type<'a>(min_indent: u16) -> impl Parser<'a, TypeAnnotation<'a>, Type<'a>> {
     map!(
         and!(
-            parse_concrete_type,
+            specialize(Type::TApply, parse_concrete_type),
             // Optionally parse space-separated arguments for the constructor,
             // e.g. `Str Float` in `Map Str Float`
-            loc_applied_args(min_indent)
+            loc_applied_args_e(min_indent)
         ),
         |(ctor, args): (TypeAnnotation<'a>, Vec<'a, Located<TypeAnnotation<'a>>>)| {
             match &ctor {
@@ -325,26 +418,56 @@ fn applied_type<'a>(min_indent: u16) -> impl Parser<'a, TypeAnnotation<'a>, Synt
     )
 }
 
-fn expression<'a>(
+fn loc_applied_args_e<'a>(
     min_indent: u16,
-) -> impl Parser<'a, Located<TypeAnnotation<'a>>, SyntaxError<'a>> {
-    use crate::blankspace::space0;
+) -> impl Parser<'a, Vec<'a, Located<TypeAnnotation<'a>>>, Type<'a>> {
+    zero_or_more!(loc_applied_arg(min_indent))
+}
+
+fn expression<'a>(min_indent: u16) -> impl Parser<'a, Located<TypeAnnotation<'a>>, Type<'a>> {
     move |arena, state: State<'a>| {
-        let (p1, first, state) = space0_before(term(min_indent), min_indent).parse(arena, state)?;
+        let (p1, first, state) = space0_before_e(
+            term(min_indent),
+            min_indent,
+            Type::TSpace,
+            Type::TIndentStart,
+        )
+        .parse(arena, state)?;
+
         let (p2, rest, state) = zero_or_more!(skip_first!(
-            ascii_char(b','),
-            space0_around(term(min_indent), min_indent)
+            word1(b',', Type::TFunctionArgument),
+            one_of![
+                space0_around_e(
+                    term(min_indent),
+                    min_indent,
+                    Type::TSpace,
+                    Type::TIndentStart
+                ),
+                |_, state: State<'a>| Err((
+                    NoProgress,
+                    Type::TFunctionArgument(state.line, state.column),
+                    state
+                ))
+            ]
         ))
         .parse(arena, state)?;
 
         // TODO this space0 is dropped, so newlines just before the function arrow when there
         // is only one argument are not seen by the formatter. Can we do better?
-        let (p3, is_function, state) =
-            optional(skip_first!(space0(min_indent), ascii_string("->"))).parse(arena, state)?;
+        let (p3, is_function, state) = optional(skip_first!(
+            space0_e(min_indent, Type::TSpace, Type::TIndentStart),
+            word2(b'-', b'>', Type::TStart)
+        ))
+        .parse(arena, state)?;
 
         if is_function.is_some() {
-            let (p4, return_type, state) =
-                space0_before(term(min_indent), min_indent).parse(arena, state)?;
+            let (p4, return_type, state) = space0_before_e(
+                term(min_indent),
+                min_indent,
+                Type::TSpace,
+                Type::TIndentStart,
+            )
+            .parse(arena, state)?;
 
             // prepare arguments
             let mut arguments = Vec::with_capacity_in(rest.len() + 1, &arena);
@@ -365,10 +488,7 @@ fn expression<'a>(
                 Ok((progress, first, state))
             } else {
                 // e.g. `Int,Int` without an arrow and return type
-                let msg =
-                    "TODO: Decide the correct error to return for 'Invalid function signature'"
-                        .to_string();
-                Err((progress, SyntaxError::NotYetImplemented(msg), state))
+                panic!()
             }
         }
     }
@@ -393,30 +513,27 @@ fn expression<'a>(
 fn parse_concrete_type<'a>(
     arena: &'a Bump,
     mut state: State<'a>,
-) -> ParseResult<'a, TypeAnnotation<'a>, SyntaxError<'a>> {
+) -> ParseResult<'a, TypeAnnotation<'a>, TApply> {
     let mut part_buf = String::new_in(arena); // The current "part" (parts are dot-separated.)
     let mut parts: Vec<&'a str> = Vec::new_in(arena);
 
-    let start_bytes_len = state.bytes.len();
-
     // Qualified types must start with a capitalized letter.
-    match peek_utf8_char(&state) {
+    match peek_utf8_char_e(&state, TApply::StartNotUppercase, TApply::Space) {
         Ok((first_letter, bytes_parsed)) => {
             if first_letter.is_alphabetic() && first_letter.is_uppercase() {
                 part_buf.push(first_letter);
             } else {
-                return Err(unexpected(arena, 0, Attempting::ConcreteType, state));
+                let problem = TApply::StartNotUppercase(state.line, state.column + 1);
+                return Err((NoProgress, problem, state));
             }
 
-            state = state.advance_without_indenting(arena, bytes_parsed)?;
+            state = state.advance_without_indenting_e(arena, bytes_parsed, TApply::Space)?;
         }
-        Err(reason) => return state.fail(arena, NoProgress, reason),
+        Err(reason) => return Err((NoProgress, reason, state)),
     }
 
-    let mut next_char = None;
-
     while !state.bytes.is_empty() {
-        match peek_utf8_char(&state) {
+        match peek_utf8_char_e(&state, TApply::End, TApply::Space) {
             Ok((ch, bytes_parsed)) => {
                 // After the first character, only these are allowed:
                 //
@@ -426,21 +543,33 @@ fn parse_concrete_type<'a>(
                 if ch.is_alphabetic() {
                     if part_buf.is_empty() && !ch.is_uppercase() {
                         // Each part must begin with a capital letter.
-                        return malformed(Some(ch), arena, state, parts);
+                        return Err((
+                            MadeProgress,
+                            TApply::StartNotUppercase(state.line, state.column),
+                            state,
+                        ));
                     }
 
                     part_buf.push(ch);
                 } else if ch.is_ascii_digit() {
                     // Parts may not start with numbers!
                     if part_buf.is_empty() {
-                        return malformed(Some(ch), arena, state, parts);
+                        return Err((
+                            MadeProgress,
+                            TApply::StartIsNumber(state.line, state.column),
+                            state,
+                        ));
                     }
 
                     part_buf.push(ch);
                 } else if ch == '.' {
                     // Having two consecutive dots is an error.
                     if part_buf.is_empty() {
-                        return malformed(Some(ch), arena, state, parts);
+                        return Err((
+                            MadeProgress,
+                            TApply::DoubleDot(state.line, state.column),
+                            state,
+                        ));
                     }
 
                     parts.push(part_buf.into_bump_str());
@@ -449,17 +578,13 @@ fn parse_concrete_type<'a>(
                     part_buf = String::new_in(arena);
                 } else {
                     // This must be the end of the type. We're done!
-                    next_char = Some(ch);
-
                     break;
                 }
 
-                state = state.advance_without_indenting(arena, bytes_parsed)?;
+                state = state.advance_without_indenting_e(arena, bytes_parsed, TApply::Space)?;
             }
             Err(reason) => {
-                let progress = Progress::from_lengths(start_bytes_len, state.bytes.len());
-
-                return state.fail(arena, progress, reason);
+                return Err((MadeProgress, reason, state));
             }
         }
     }
@@ -471,14 +596,11 @@ fn parse_concrete_type<'a>(
         //
         // If we made it this far and don't have a next_char, then necessarily
         // we have consumed a '.' char previously.
-        return malformed(next_char.or(Some('.')), arena, state, parts);
-    }
-
-    if part_buf.is_empty() {
-        // We had neither capitalized nor noncapitalized parts,
-        // yet we made it this far. The only explanation is that this was
-        // a stray '.' drifting through the cosmos.
-        return Err(unexpected(arena, 1, Attempting::Identifier, state));
+        return Err((
+            MadeProgress,
+            TApply::TrailingDot(state.line, state.column),
+            state,
+        ));
     }
 
     let answer = TypeAnnotation::Apply(
@@ -487,37 +609,37 @@ fn parse_concrete_type<'a>(
         &[],
     );
 
-    let progress = Progress::from_lengths(start_bytes_len, state.bytes.len());
-    Ok((progress, answer, state))
+    Ok((MadeProgress, answer, state))
 }
 
 fn parse_type_variable<'a>(
     arena: &'a Bump,
     mut state: State<'a>,
-) -> ParseResult<'a, TypeAnnotation<'a>, SyntaxError<'a>> {
+) -> ParseResult<'a, TypeAnnotation<'a>, TVariable> {
     let mut buf = String::new_in(arena);
 
     let start_bytes_len = state.bytes.len();
 
-    match peek_utf8_char(&state) {
+    match peek_utf8_char_e(&state, TVariable::StartNotLowercase, TVariable::Space) {
         Ok((first_letter, bytes_parsed)) => {
             // Type variables must start with a lowercase letter.
             if first_letter.is_alphabetic() && first_letter.is_lowercase() {
                 buf.push(first_letter);
             } else {
-                return Err(unexpected(arena, 0, Attempting::TypeVariable, state));
+                return Err((
+                    NoProgress,
+                    TVariable::StartNotLowercase(state.line, state.column),
+                    state,
+                ));
             }
 
-            state = state.advance_without_indenting(arena, bytes_parsed)?;
-        }
-        Err(reason) => {
-            let progress = Progress::from_lengths(start_bytes_len, state.bytes.len());
-            return state.fail(arena, progress, reason);
+            state = state.advance_without_indenting_e(arena, bytes_parsed, TVariable::Space)?;
         }
+        Err(reason) => return Err((NoProgress, reason, state)),
     }
 
     while !state.bytes.is_empty() {
-        match peek_utf8_char(&state) {
+        match peek_utf8_char_e(&state, TVariable::End, TVariable::Space) {
             Ok((ch, bytes_parsed)) => {
                 // After the first character, only these are allowed:
                 //
@@ -530,11 +652,10 @@ fn parse_type_variable<'a>(
                     break;
                 }
 
-                state = state.advance_without_indenting(arena, bytes_parsed)?;
+                state = state.advance_without_indenting_e(arena, bytes_parsed, TVariable::Space)?;
             }
             Err(reason) => {
-                let progress = Progress::from_lengths(start_bytes_len, state.bytes.len());
-                return state.fail(arena, progress, reason);
+                return state.fail(arena, MadeProgress, reason);
             }
         }
     }
@@ -544,45 +665,3 @@ fn parse_type_variable<'a>(
     let progress = Progress::from_lengths(start_bytes_len, state.bytes.len());
     Ok((progress, answer, state))
 }
-
-fn malformed<'a>(
-    opt_bad_char: Option<char>,
-    arena: &'a Bump,
-    mut state: State<'a>,
-    parts: Vec<&'a str>,
-) -> ParseResult<'a, TypeAnnotation<'a>, SyntaxError<'a>> {
-    // assumption: progress was made to conclude that the annotation is malformed
-
-    // Reconstruct the original string that we've been parsing.
-    let mut full_string = String::new_in(arena);
-
-    full_string.push_str(arena_join(arena, &mut parts.into_iter(), ".").into_bump_str());
-
-    if let Some(bad_char) = opt_bad_char {
-        full_string.push(bad_char);
-    }
-
-    // Consume the remaining chars in the identifier.
-    while !state.bytes.is_empty() {
-        match peek_utf8_char(&state) {
-            Ok((ch, bytes_parsed)) => {
-                // We can't use ch.is_alphanumeric() here because that passes for
-                // things that are "numeric" but not ASCII digits, like `¾`
-                if ch == '.' || ch.is_alphabetic() || ch.is_ascii_digit() {
-                    full_string.push(ch);
-                } else {
-                    break;
-                }
-
-                state = state.advance_without_indenting(arena, bytes_parsed)?;
-            }
-            Err(reason) => return state.fail(arena, MadeProgress, reason),
-        }
-    }
-
-    Ok((
-        MadeProgress,
-        TypeAnnotation::Malformed(full_string.into_bump_str()),
-        state,
-    ))
-}
diff --git a/compiler/reporting/src/error/parse.rs b/compiler/reporting/src/error/parse.rs
index 0fb170c0d9..fc8082c6b6 100644
--- a/compiler/reporting/src/error/parse.rs
+++ b/compiler/reporting/src/error/parse.rs
@@ -31,7 +31,7 @@ fn note_for_tag_union_type_indent<'a>(alloc: &'a RocDocAllocator<'a>) -> RocDocB
 fn hint_for_tag_name<'a>(alloc: &'a RocDocAllocator<'a>) -> RocDocBuilder<'a> {
     alloc.concat(vec![
         alloc.hint("Tag names "),
-        alloc.reflow("Tag names start with an uppercase letter, like "),
+        alloc.reflow("start with an uppercase letter, like "),
         alloc.parser_suggestion("Err"),
         alloc.text(" or "),
         alloc.parser_suggestion("Green"),
@@ -39,6 +39,17 @@ fn hint_for_tag_name<'a>(alloc: &'a RocDocAllocator<'a>) -> RocDocBuilder<'a> {
     ])
 }
 
+fn hint_for_private_tag_name<'a>(alloc: &'a RocDocAllocator<'a>) -> RocDocBuilder<'a> {
+    alloc.concat(vec![
+        alloc.hint("Private tag names "),
+        alloc.reflow("start with an `@` symbol followed by an uppercase letter, like "),
+        alloc.parser_suggestion("@UID"),
+        alloc.text(" or "),
+        alloc.parser_suggestion("@SecretKey"),
+        alloc.text("."),
+    ])
+}
+
 fn to_syntax_report<'a>(
     alloc: &'a RocDocAllocator<'a>,
     filename: PathBuf,
@@ -102,6 +113,24 @@ fn to_syntax_report<'a>(
 
             report(doc)
         }
+        SyntaxError::Eof(region) => {
+            let doc = alloc.stack(vec![alloc.reflow("End of Field"), alloc.region(*region)]);
+
+            Report {
+                filename,
+                doc,
+                title: "PARSE PROBLEM".to_string(),
+            }
+        }
+        SyntaxError::OutdentedTooFar => {
+            let doc = alloc.stack(vec![alloc.reflow("OutdentedTooFar")]);
+
+            Report {
+                filename,
+                doc,
+                title: "PARSE PROBLEM".to_string(),
+            }
+        }
         Type(typ) => to_type_report(alloc, filename, &typ, 0, 0),
         _ => todo!("unhandled parse error: {:?}", parse_problem),
     }
@@ -111,8 +140,8 @@ fn to_type_report<'a>(
     alloc: &'a RocDocAllocator<'a>,
     filename: PathBuf,
     parse_problem: &roc_parse::parser::Type<'a>,
-    _start_row: Row,
-    _start_col: Col,
+    start_row: Row,
+    start_col: Col,
 ) -> Report<'a> {
     use roc_parse::parser::Type;
 
@@ -121,6 +150,82 @@ fn to_type_report<'a>(
         Type::TTagUnion(tag_union, row, col) => {
             to_ttag_union_report(alloc, filename, &tag_union, *row, *col)
         }
+        Type::TInParens(tinparens, row, col) => {
+            to_tinparens_report(alloc, filename, &tinparens, *row, *col)
+        }
+        Type::TApply(tapply, row, col) => to_tapply_report(alloc, filename, &tapply, *row, *col),
+
+        Type::TFunctionArgument(row, col) => match what_is_next(alloc.src_lines, *row, *col) {
+            Next::Other(Some(',')) => {
+                let surroundings = Region::from_rows_cols(start_row, start_col, *row, *col);
+                let region = Region::from_row_col(*row, *col);
+
+                let doc = alloc.stack(vec![
+                    alloc.reflow(r"I just started parsing a function argument type, but I encounterd two commas in a row:"),
+                    alloc.region_with_subregion(surroundings, region),
+                    alloc.concat(vec![alloc.reflow("Try removing one of them.")]),
+                ]);
+
+                Report {
+                    filename,
+                    doc,
+                    title: "DOUBLE COMMA".to_string(),
+                }
+            }
+            _ => todo!(),
+        },
+
+        Type::TStart(row, col) => {
+            let surroundings = Region::from_rows_cols(start_row, start_col, *row, *col);
+            let region = Region::from_row_col(*row, *col);
+
+            let doc = alloc.stack(vec![
+                alloc.reflow(r"I just started parsing a type, but I got stuck here:"),
+                alloc.region_with_subregion(surroundings, region),
+                alloc.note("I may be confused by indentation"),
+            ]);
+
+            Report {
+                filename,
+                doc,
+                title: "UNFINISHED TYPE".to_string(),
+            }
+        }
+
+        Type::TIndentStart(row, col) => {
+            let surroundings = Region::from_rows_cols(start_row, start_col, *row, *col);
+            let region = Region::from_row_col(*row, *col);
+
+            let doc = alloc.stack(vec![
+                alloc.reflow(r"I just started parsing a type, but I got stuck here:"),
+                alloc.region_with_subregion(surroundings, region),
+                alloc.note("I may be confused by indentation"),
+            ]);
+
+            Report {
+                filename,
+                doc,
+                title: "UNFINISHED TYPE".to_string(),
+            }
+        }
+
+        Type::TAsIndentStart(row, col) => {
+            let surroundings = Region::from_rows_cols(start_row, start_col, *row, *col);
+            let region = Region::from_row_col(*row, *col);
+
+            let doc = alloc.stack(vec![
+                alloc.reflow(r"I just started parsing an inline type alias, but I got stuck here:"),
+                alloc.region_with_subregion(surroundings, region),
+                alloc.note("I may be confused by indentation"),
+            ]);
+
+            Report {
+                filename,
+                doc,
+                title: "UNFINISHED INLINE ALIAS".to_string(),
+            }
+        }
+
         _ => todo!("unhandled type parse error: {:?}", &parse_problem),
     }
 }
@@ -278,8 +383,6 @@ fn to_trecord_report<'a>(
 
         TRecord::Type(tipe, row, col) => to_type_report(alloc, filename, tipe, row, col),
 
-        TRecord::Syntax(error, row, col) => to_syntax_report(alloc, filename, error, row, col),
-
         TRecord::IndentOpen(row, col) => {
             let surroundings = Region::from_rows_cols(start_row, start_col, row, col);
             let region = Region::from_row_col(row, col);
@@ -303,7 +406,7 @@ fn to_trecord_report<'a>(
         }
 
         TRecord::IndentEnd(row, col) => {
-            match next_line_starts_with_close_curly(alloc.src_lines, row - 1) {
+            match next_line_starts_with_close_curly(alloc.src_lines, row.saturating_sub(1)) {
                 Some((curly_row, curly_col)) => {
                     let surroundings =
                         Region::from_rows_cols(start_row, start_col, curly_row, curly_col);
@@ -373,8 +476,6 @@ fn to_ttag_union_report<'a>(
 ) -> Report<'a> {
     use roc_parse::parser::TTagUnion;
 
-    dbg!(parse_problem);
-
     match *parse_problem {
         TTagUnion::Open(row, col) => match what_is_next(alloc.src_lines, row, col) {
             Next::Keyword(keyword) => {
@@ -463,6 +564,22 @@ fn to_ttag_union_report<'a>(
                         title: "WEIRD TAG NAME".to_string(),
                     }
                 }
+                Next::Other(Some('@')) => {
+                    let doc = alloc.stack(vec![
+                        alloc.reflow(
+                            r"I am partway through parsing a tag union type, but I got stuck here:",
+                        ),
+                        alloc.region_with_subregion(surroundings, region),
+                        alloc.reflow(r"I was expecting to see a private tag name."),
+                        hint_for_private_tag_name(alloc),
+                    ]);
+
+                    Report {
+                        filename,
+                        doc,
+                        title: "WEIRD TAG NAME".to_string(),
+                    }
+                }
                 _ => {
                     let doc = alloc.stack(vec![
                         alloc.reflow(r"I am partway through parsing a tag union type, but I got stuck here:"),
@@ -487,8 +604,6 @@ fn to_ttag_union_report<'a>(
 
         TTagUnion::Type(tipe, row, col) => to_type_report(alloc, filename, tipe, row, col),
 
-        TTagUnion::Syntax(error, row, col) => to_syntax_report(alloc, filename, error, row, col),
-
         TTagUnion::IndentOpen(row, col) => {
             let surroundings = Region::from_rows_cols(start_row, start_col, row, col);
             let region = Region::from_row_col(row, col);
@@ -565,6 +680,320 @@ fn to_ttag_union_report<'a>(
     }
 }
 
+fn to_tinparens_report<'a>(
+    alloc: &'a RocDocAllocator<'a>,
+    filename: PathBuf,
+    parse_problem: &roc_parse::parser::TInParens<'a>,
+    start_row: Row,
+    start_col: Col,
+) -> Report<'a> {
+    use roc_parse::parser::TInParens;
+
+    match *parse_problem {
+        TInParens::Open(row, col) => {
+            match what_is_next(alloc.src_lines, row, col) {
+                Next::Keyword(keyword) => {
+                    let surroundings = Region::from_rows_cols(start_row, start_col, row, col);
+                    let region = to_keyword_region(row, col, keyword);
+
+                    let doc = alloc.stack(vec![
+                    alloc.reflow(r"I just saw an open parenthesis, so I was expecting to see a type next."),
+                    alloc.region_with_subregion(surroundings, region),
+                    alloc.concat(vec![
+                        alloc.reflow(r"Something like "),
+                        alloc.parser_suggestion("(List Person)"),
+                        alloc.text(" or "),
+                        alloc.parser_suggestion("(Result I64 Str)"),
+                    ]),
+                ]);
+
+                    Report {
+                        filename,
+                        doc,
+                        title: "UNFINISHED PARENTHESES".to_string(),
+                    }
+                }
+                Next::Other(Some(c)) if c.is_alphabetic() => {
+                    debug_assert!(c.is_lowercase());
+
+                    let surroundings = Region::from_rows_cols(start_row, start_col, row, col);
+                    let region = Region::from_row_col(row, col);
+
+                    let doc = alloc.stack(vec![
+                    alloc.reflow(
+                        r"I am partway through parsing a type in parentheses, but I got stuck here:",
+                    ),
+                    alloc.region_with_subregion(surroundings, region),
+                    alloc.reflow(r"I was expecting to see a tag name."),
+                    hint_for_tag_name(alloc),
+                ]);
+
+                    Report {
+                        filename,
+                        doc,
+                        title: "WEIRD TAG NAME".to_string(),
+                    }
+                }
+                _ => {
+                    let surroundings = Region::from_rows_cols(start_row, start_col, row, col);
+                    let region = Region::from_row_col(row, col);
+
+                    let doc = alloc.stack(vec![
+                        alloc.reflow(
+                            r"I just started parsing a type in parentheses, but I got stuck here:",
+                        ),
+                        alloc.region_with_subregion(surroundings, region),
+                        alloc.concat(vec![
+                            alloc.reflow(r"Tag unions look like "),
+                            alloc.parser_suggestion("[ Many I64, None ],"),
+                            alloc.reflow(" so I was expecting to see a tag name next."),
+                        ]),
+                    ]);
+
+                    Report {
+                        filename,
+                        doc,
+                        title: "UNFINISHED PARENTHESES".to_string(),
+                    }
+                }
+            }
+        }
+
+        TInParens::End(row, col) => {
+            let surroundings = Region::from_rows_cols(start_row, start_col, row, col);
+            let region = Region::from_row_col(row, col);
+
+            match what_is_next(alloc.src_lines, row, col) {
+                Next::Other(Some(c)) if c.is_alphabetic() => {
+                    debug_assert!(c.is_lowercase());
+
+                    // TODO hint for tuples?
+                    let doc = alloc.stack(vec![
+                        alloc.reflow(
+                            r"I am partway through parsing a type in parentheses, but I got stuck here:",
+                        ),
+                        alloc.region_with_subregion(surroundings, region),
+                        alloc.reflow(r"I was expecting to see a tag name."),
+                        hint_for_tag_name(alloc),
+                    ]);
+
+                    Report {
+                        filename,
+                        doc,
+                        title: "WEIRD TAG NAME".to_string(),
+                    }
+                }
+                _ => {
+                    let doc = alloc.stack(vec![
+                        alloc.reflow(r"I am partway through parsing a type in parentheses, but I got stuck here:"),
+                        alloc.region_with_subregion(surroundings, region),
+                        alloc.concat(vec![
+                                alloc.reflow(
+                                    r"I was expecting to see a closing parenthesis before this, so try adding a ",
+                                ),
+                                alloc.parser_suggestion(")"),
+                                alloc.reflow(" and see if that helps?"),
+                            ]),
+                        ]);
+
+                    Report {
+                        filename,
+                        doc,
+                        title: "UNFINISHED PARENTHESES".to_string(),
+                    }
+                }
+            }
+        }
+
+        TInParens::Type(tipe, row, col) => to_type_report(alloc, filename, tipe, row, col),
+
+        TInParens::IndentOpen(row, col) => {
+            let surroundings = Region::from_rows_cols(start_row, start_col, row, col);
+            let region = Region::from_row_col(row, col);
+
+            let doc = alloc.stack(vec![
+                alloc
+                    .reflow(r"I just started parsing a type in parentheses, but I got stuck here:"),
+                alloc.region_with_subregion(surroundings, region),
+                alloc.concat(vec![
+                    alloc.reflow(r"Tag unions look like "),
+                    alloc.parser_suggestion("[ Many I64, None ],"),
+                    alloc.reflow(" so I was expecting to see a tag name next."),
+                ]),
+                note_for_tag_union_type_indent(alloc),
+            ]);
+
+            Report {
+                filename,
+                doc,
+                title: "UNFINISHED PARENTHESES".to_string(),
+            }
+        }
+
+        TInParens::IndentEnd(row, col) => {
+            match next_line_starts_with_close_square_bracket(alloc.src_lines, row - 1) {
+                Some((curly_row, curly_col)) => {
+                    let surroundings =
+                        Region::from_rows_cols(start_row, start_col, curly_row, curly_col);
+                    let region = Region::from_row_col(curly_row, curly_col);
+
+                    let doc = alloc.stack(vec![
+                        alloc.reflow(
+                            "I am partway through parsing a type in parentheses, but I got stuck here:",
+                        ),
+                        alloc.region_with_subregion(surroundings, region),
+                        alloc.concat(vec![
+                            alloc.reflow("I need this square bracket to be indented more. Try adding more spaces before it!"),
+                        ]),
+                    ]);
+
+                    Report {
+                        filename,
+                        doc,
+                        title: "NEED MORE INDENTATION".to_string(),
+                    }
+                }
+                None => {
+                    let surroundings = Region::from_rows_cols(start_row, start_col, row, col);
+                    let region = Region::from_row_col(row, col);
+
+                    let doc = alloc.stack(vec![
+                        alloc.reflow(
+                            r"I am partway through parsing a type in parentheses, but I got stuck here:",
+                        ),
+                        alloc.region_with_subregion(surroundings, region),
+                        alloc.concat(vec![
+                            alloc.reflow("I was expecting to see a closing square "),
+                            alloc.reflow("bracket before this, so try adding a "),
+                            alloc.parser_suggestion("]"),
+                            alloc.reflow(" and see if that helps?"),
+                        ]),
+                        note_for_tag_union_type_indent(alloc),
+                    ]);
+
+                    Report {
+                        filename,
+                        doc,
+                        title: "UNFINISHED PARENTHESES".to_string(),
+                    }
+                }
+            }
+        }
+
+        TInParens::Space(error, row, col) => to_space_report(alloc, filename, &error, row, col),
+    }
+}
+
+fn to_tapply_report<'a>(
+    alloc: &'a RocDocAllocator<'a>,
+    filename: PathBuf,
+    parse_problem: &roc_parse::parser::TApply,
+    _start_row: Row,
+    _start_col: Col,
+) -> Report<'a> {
+    use roc_parse::parser::TApply;
+
+    match *parse_problem {
+        TApply::DoubleDot(row, col) => {
+            let region = Region::from_row_col(row, col);
+
+            let doc = alloc.stack(vec![
+                alloc.reflow(r"I encountered two dots in a row:"),
+                alloc.region(region),
+                alloc.concat(vec![alloc.reflow("Try removing one of them.")]),
+            ]);
+
+            Report {
+                filename,
+                doc,
+                title: "DOUBLE DOT".to_string(),
+            }
+        }
+        TApply::TrailingDot(row, col) => {
+            let region = Region::from_row_col(row, col);
+
+            let doc = alloc.stack(vec![
+                alloc.reflow(r"I encountered a dot with nothing after it:"),
+                alloc.region(region),
+                alloc.concat(vec![
+                    alloc.reflow("Dots are used to refer to a type in a qualified way, like "),
+                    alloc.parser_suggestion("Num.I64"),
+                    alloc.text(" or "),
+                    alloc.parser_suggestion("List.List a"),
+                    alloc.reflow(". Try adding a type name next."),
+                ]),
+            ]);
+
+            Report {
+                filename,
+                doc,
+                title: "TRAILING DOT".to_string(),
+            }
+        }
+        TApply::StartIsNumber(row, col) => {
+            let region = Region::from_row_col(row, col);
+
+            let doc = alloc.stack(vec![
+                alloc.reflow(r"I encountered a number at the start of a qualified name segment:"),
+                alloc.region(region),
+                alloc.concat(vec![
+                    alloc.reflow("All parts of a qualified type name must start with an uppercase letter, like "),
+                    alloc.parser_suggestion("Num.I64"),
+                    alloc.text(" or "),
+                    alloc.parser_suggestion("List.List a"),
+                    alloc.text("."),
+                ]),
+            ]);
+
+            Report {
+                filename,
+                doc,
+                title: "WEIRD QUALIFIED NAME".to_string(),
+            }
+        }
+        TApply::StartNotUppercase(row, col) => {
+            let region = Region::from_row_col(row, col);
+
+            let doc = alloc.stack(vec![
+                alloc.reflow(r"I encountered a lowercase letter at the start of a qualified name segment:"),
+                alloc.region(region),
+                alloc.concat(vec![
+                    alloc.reflow("All parts of a qualified type name must start with an uppercase letter, like "),
+                    alloc.parser_suggestion("Num.I64"),
+                    alloc.text(" or "),
+                    alloc.parser_suggestion("List.List a"),
+                    alloc.text("."),
+                ]),
+            ]);
+
+            Report {
+                filename,
+                doc,
+                title: "WEIRD QUALIFIED NAME".to_string(),
+            }
+        }
+
+        TApply::End(row, col) => {
+            let region = Region::from_row_col(row, col);
+
+            let doc = alloc.stack(vec![
+                alloc.reflow(
+                    r"I reached the end of the input file while parsing a qualified type name",
+                ),
+                alloc.region(region),
+            ]);
+
+            Report {
+                filename,
+                doc,
+                title: "END OF FILE".to_string(),
+            }
+        }
+
+        TApply::Space(error, row, col) => to_space_report(alloc, filename, &error, row, col),
+    }
+}
+
 fn to_space_report<'a>(
     alloc: &'a RocDocAllocator<'a>,
     filename: PathBuf,
diff --git a/compiler/reporting/tests/test_reporting.rs b/compiler/reporting/tests/test_reporting.rs
index 986a877743..7b50c9e5a8 100644
--- a/compiler/reporting/tests/test_reporting.rs
+++ b/compiler/reporting/tests/test_reporting.rs
@@ -4027,7 +4027,8 @@ mod test_reporting {
     }
 
     #[test]
-    fn type_annotation_dubble_colon() {
+    #[ignore]
+    fn type_annotation_double_colon() {
         report_problem_as(
             indoc!(
                 r#"
@@ -4172,8 +4173,7 @@ mod test_reporting {
                 
                 I was expecting to see a tag name.
                 
-                Hint: Tag names Tag names start with an uppercase letter, like
-                Err or Green.
+                Hint: Tag names start with an uppercase letter, like Err or Green.
             "#
             ),
         )
@@ -4198,8 +4198,7 @@ mod test_reporting {
                 
                 I was expecting to see a tag name.
                 
-                Hint: Tag names Tag names start with an uppercase letter, like
-                Err or Green.
+                Hint: Tag names start with an uppercase letter, like Err or Green.
             "#
             ),
         )
@@ -4245,8 +4244,7 @@ mod test_reporting {
                 I am partway through parsing a record type, but I got stuck here:
                 
                 1│  f : {
-                2│  foo : I64,
-                    ^
+                         ^
                 
                 I was expecting to see a closing curly brace before this, so try
                 adding a } and see if that helps?
@@ -4396,4 +4394,313 @@ mod test_reporting {
             ),
         )
     }
+
+    #[test]
+    #[ignore]
+    fn type_in_parens_start() {
+        report_problem_as(
+            indoc!(
+                r#"
+                f : (
+                "#
+            ),
+            indoc!(
+                r#"
+                ── UNFINISHED RECORD TYPE ──────────────────────────────────────────────────────
+                
+                I am partway through parsing a record type, but I got stuck here:
+                
+                1│  f : { a: Int, 
+                                 ^
+                
+                I was expecting to see a closing curly brace before this, so try
+                adding a } and see if that helps?
+            "#
+            ),
+        )
+    }
+
+    #[test]
+    fn type_in_parens_end() {
+        report_problem_as(
+            indoc!(
+                r#"
+                f : ( I64
+                "#
+            ),
+            indoc!(
+                r#"
+                ── UNFINISHED PARENTHESES ──────────────────────────────────────────────────────
+                
+                I am partway through parsing a type in parentheses, but I got stuck
+                here:
+                
+                1│  f : ( I64
+                             ^
+                
+                I was expecting to see a closing parenthesis before this, so try
+                adding a ) and see if that helps?
+            "#
+            ),
+        )
+    }
+
+    #[test]
+    fn type_apply_double_dot() {
+        report_problem_as(
+            indoc!(
+                r#"
+                f : Foo..Bar 
+                "#
+            ),
+            indoc!(
+                r#"
+                ── DOUBLE DOT ──────────────────────────────────────────────────────────────────
+                
+                I encountered two dots in a row:
+                
+                1│  f : Foo..Bar 
+                            ^
+                
+                Try removing one of them.
+            "#
+            ),
+        )
+    }
+
+    #[test]
+    fn type_apply_trailing_dot() {
+        report_problem_as(
+            indoc!(
+                r#"
+                f : Foo.Bar.
+                "#
+            ),
+            indoc!(
+                r#"
+                ── TRAILING DOT ────────────────────────────────────────────────────────────────
+                
+                I encountered a dot with nothing after it:
+                
+                1│  f : Foo.Bar.
+                                ^
+                
+                Dots are used to refer to a type in a qualified way, like
+                Num.I64 or List.List a. Try adding a type name next.
+            "#
+            ),
+        )
+    }
+
+    #[test]
+    #[ignore]
+    fn type_apply_stray_dot() {
+        // TODO good message
+        report_problem_as(
+            indoc!(
+                r#"
+                f : . 
+                "#
+            ),
+            indoc!(
+                r#"
+                ── UNFINISHED PARENTHESES ──────────────────────────────────────────────────────
+                
+                I am partway through parsing a type in parentheses, but I got stuck
+                here:
+                
+                1│  f : ( I64
+                             ^
+                
+                I was expecting to see a closing parenthesis before this, so try
+                adding a ) and see if that helps?
+            "#
+            ),
+        )
+    }
+
+    #[test]
+    fn type_apply_start_with_number() {
+        report_problem_as(
+            indoc!(
+                r#"
+                f : Foo.1
+                "#
+            ),
+            indoc!(
+                r#"
+                ── WEIRD QUALIFIED NAME ────────────────────────────────────────────────────────
+                
+                I encountered a number at the start of a qualified name segment:
+                
+                1│  f : Foo.1
+                            ^
+                
+                All parts of a qualified type name must start with an uppercase
+                letter, like Num.I64 or List.List a.
+            "#
+            ),
+        )
+    }
+
+    #[test]
+    fn type_apply_start_with_lowercase() {
+        report_problem_as(
+            indoc!(
+                r#"
+                f : Foo.foo
+                "#
+            ),
+            indoc!(
+                r#"
+                ── WEIRD QUALIFIED NAME ────────────────────────────────────────────────────────
+                
+                I encountered a lowercase letter at the start of a qualified name
+                segment:
+                
+                1│  f : Foo.foo
+                            ^
+                
+                All parts of a qualified type name must start with an uppercase
+                letter, like Num.I64 or List.List a.
+            "#
+            ),
+        )
+    }
+
+    #[test]
+    fn type_inline_alias() {
+        report_problem_as(
+            indoc!(
+                r#"
+                f : I64 as 
+                f = 0
+
+                f
+                "#
+            ),
+            indoc!(
+                r#"
+                ── UNFINISHED INLINE ALIAS ─────────────────────────────────────────────────────
+                
+                I just started parsing an inline type alias, but I got stuck here:
+                
+                1│  f : I64 as 
+                              ^
+                
+                Note: I may be confused by indentation
+            "#
+            ),
+        )
+    }
+
+    #[test]
+    fn type_double_comma() {
+        report_problem_as(
+            indoc!(
+                r#"
+                f : I64,,I64 -> I64 
+                f = 0
+
+                f
+                "#
+            ),
+            indoc!(
+                r#"
+                ── DOUBLE COMMA ────────────────────────────────────────────────────────────────
+                
+                I just started parsing a function argument type, but I encounterd two
+                commas in a row:
+                
+                1│  f : I64,,I64 -> I64 
+                            ^
+                
+                Try removing one of them.
+            "#
+            ),
+        )
+    }
+
+    #[test]
+    fn type_argument_no_arrow() {
+        report_problem_as(
+            indoc!(
+                r#"
+                f : I64, I64 
+                f = 0
+
+                f
+                "#
+            ),
+            indoc!(
+                r#"
+                ── UNFINISHED TYPE ─────────────────────────────────────────────────────────────
+                
+                I just started parsing a type, but I got stuck here:
+                
+                1│  f : I64, I64 
+                                ^
+                
+                Note: I may be confused by indentation
+            "#
+            ),
+        )
+    }
+
+    #[test]
+    fn type_argument_arrow_then_nothing() {
+        // TODO could do better by pointing out we're parsing a function type
+        report_problem_as(
+            indoc!(
+                r#"
+                f : I64, I64 -> 
+                f = 0
+
+                f
+                "#
+            ),
+            indoc!(
+                r#"
+                ── UNFINISHED TYPE ─────────────────────────────────────────────────────────────
+                
+                I just started parsing a type, but I got stuck here:
+                
+                1│  f : I64, I64 -> 
+                                   ^
+                
+                Note: I may be confused by indentation
+            "#
+            ),
+        )
+    }
+
+    #[test]
+    fn invalid_private_tag_name() {
+        // TODO could do better by pointing out we're parsing a function type
+        report_problem_as(
+            indoc!(
+                r#"
+                f : [ @Foo Bool, @100 I64 ] 
+                f = 0
+
+                f
+                "#
+            ),
+            indoc!(
+                r#"
+                ── WEIRD TAG NAME ──────────────────────────────────────────────────────────────
+                
+                I am partway through parsing a tag union type, but I got stuck here:
+                
+                1│  f : [ @Foo Bool, @100 I64 ] 
+                                     ^
+                
+                I was expecting to see a private tag name.
+                
+                Hint: Private tag names start with a `@` symbol followed by an
+                uppercase letter, like @UID or @SecretKey.
+            "#
+            ),
+        )
+    }
 }
diff --git a/editor/src/keyboard_input.rs b/editor/src/keyboard_input.rs
index 0a976a1a0f..457f27d50c 100644
--- a/editor/src/keyboard_input.rs
+++ b/editor/src/keyboard_input.rs
@@ -38,6 +38,9 @@ pub fn handle_keydown(
                 handle_cut(app_model)?
             }
         }
+
+        A => pass_keydown_to_focused(&modifiers, virtual_keycode, app_model),
+
         _ => (),
     }
 
diff --git a/editor/src/mvc/ed_update.rs b/editor/src/mvc/ed_update.rs
index 83cb701aec..27247c11fe 100644
--- a/editor/src/mvc/ed_update.rs
+++ b/editor/src/mvc/ed_update.rs
@@ -318,6 +318,20 @@ fn del_selection(selection: RawSelection, ed_model: &mut EdModel) -> EdResult<()
     Ok(())
 }
 
+// TODO move this to impl EdModel
+pub fn handle_select_all(ed_model: &mut EdModel) {
+    if ed_model.text_buf.nr_of_chars() > 0 {
+        let last_pos = ed_model.text_buf.last_position();
+
+        ed_model.selection_opt = Some(RawSelection {
+            start_pos: Position { line: 0, column: 0 },
+            end_pos: last_pos,
+        });
+
+        ed_model.caret_pos = last_pos;
+    }
+}
+
 pub fn handle_new_char(received_char: &char, ed_model: &mut EdModel) -> EdResult<()> {
     let old_caret_pos = ed_model.caret_pos;
 
@@ -351,7 +365,8 @@ pub fn handle_new_char(received_char: &char, ed_model: &mut EdModel) -> EdResult
 
             ed_model.selection_opt = None;
         }
-        '\u{3}' // Ctrl + C
+        '\u{1}' // Ctrl + A
+        | '\u{3}' // Ctrl + C
         | '\u{16}' // Ctrl + V
         | '\u{18}' // Ctrl + X
         | '\u{e000}'..='\u{f8ff}' // http://www.unicode.org/faq/private_use.html
@@ -397,6 +412,12 @@ pub fn handle_key_down(
         Up => handle_arrow(move_caret_up, modifiers, ed_model),
         Right => handle_arrow(move_caret_right, modifiers, ed_model),
         Down => handle_arrow(move_caret_down, modifiers, ed_model),
+
+        A => {
+            if modifiers.ctrl() {
+                handle_select_all(ed_model)
+            }
+        }
         _ => {}
     }
 }
@@ -405,7 +426,7 @@ pub fn handle_key_down(
 pub mod test_ed_update {
     use crate::mvc::app_update::test_app_update::mock_app_model;
     use crate::mvc::ed_model::{Position, RawSelection};
-    use crate::mvc::ed_update::handle_new_char;
+    use crate::mvc::ed_update::{handle_new_char, handle_select_all};
     use crate::selection::test_selection::{
         all_lines_vec, convert_dsl_to_selection, convert_selection_to_dsl, text_buffer_from_dsl_str,
     };
@@ -554,4 +575,51 @@ pub mod test_ed_update {
 
         Ok(())
     }
+
+    fn assert_select_all(
+        pre_lines_str: &[&str],
+        expected_post_lines_str: &[&str],
+    ) -> Result<(), String> {
+        let (caret_pos, selection_opt, pre_text_buf) = gen_caret_text_buf(pre_lines_str)?;
+
+        let app_model = mock_app_model(pre_text_buf, caret_pos, selection_opt, None);
+        let mut ed_model = app_model.ed_model_opt.unwrap();
+
+        handle_select_all(&mut ed_model);
+
+        let mut text_buf_lines = all_lines_vec(&ed_model.text_buf);
+        let post_lines_str = convert_selection_to_dsl(
+            ed_model.selection_opt,
+            ed_model.caret_pos,
+            &mut text_buf_lines,
+        )?;
+
+        assert_eq!(post_lines_str, expected_post_lines_str);
+
+        Ok(())
+    }
+
+    #[test]
+    fn select_all() -> Result<(), String> {
+        assert_select_all(&["|"], &["|"])?;
+        assert_select_all(&["|a"], &["[a]|"])?;
+        assert_select_all(&["a|"], &["[a]|"])?;
+        assert_select_all(&["abc d|ef ghi"], &["[abc def ghi]|"])?;
+        assert_select_all(&["[a]|"], &["[a]|"])?;
+        assert_select_all(&["|[a]"], &["[a]|"])?;
+        assert_select_all(&["|[abc def ghi]"], &["[abc def ghi]|"])?;
+        assert_select_all(&["a\n", "[b\n", "]|"], &["[a\n", "b\n", "]|"])?;
+        assert_select_all(&["a\n", "[b]|\n", ""], &["[a\n", "b\n", "]|"])?;
+        assert_select_all(&["a\n", "|[b\n", "]"], &["[a\n", "b\n", "]|"])?;
+        assert_select_all(
+            &["abc\n", "def\n", "gh|i\n", "jkl"],
+            &["[abc\n", "def\n", "ghi\n", "jkl]|"],
+        )?;
+        assert_select_all(
+            &["|[abc\n", "def\n", "ghi\n", "jkl]"],
+            &["[abc\n", "def\n", "ghi\n", "jkl]|"],
+        )?;
+
+        Ok(())
+    }
 }
diff --git a/editor/src/text_buffer.rs b/editor/src/text_buffer.rs
index f43d0260ff..a0a512883c 100644
--- a/editor/src/text_buffer.rs
+++ b/editor/src/text_buffer.rs
@@ -116,6 +116,10 @@ impl TextBuffer {
         self.text_rope.len_lines()
     }
 
+    pub fn nr_of_chars(&self) -> usize {
+        self.text_rope.len_chars()
+    }
+
     // expensive function, don't use it if it can be done with a specialized, more efficient function
     // TODO use pool allocation here
     pub fn all_lines<'a>(&self, arena: &'a Bump) -> BumpString<'a> {
@@ -132,6 +136,16 @@ impl TextBuffer {
         self.text_rope.line_to_char(pos.line) + pos.column
     }
 
+    fn char_indx_to_pos(&self, char_indx: usize) -> Position {
+        let line = self.text_rope.char_to_line(char_indx);
+
+        let char_idx_line_start = self.pos_to_char_indx(Position { line, column: 0 });
+
+        let column = char_indx - char_idx_line_start;
+
+        Position { line, column }
+    }
+
     fn sel_to_tup(&self, raw_sel: RawSelection) -> EdResult<(usize, usize)> {
         let valid_sel = validate_selection(raw_sel)?;
         let start_char_indx = self.pos_to_char_indx(valid_sel.selection.start_pos);
@@ -139,6 +153,10 @@ impl TextBuffer {
 
         Ok((start_char_indx, end_char_indx))
     }
+
+    pub fn last_position(&self) -> Position {
+        self.char_indx_to_pos(self.nr_of_chars())
+    }
 }
 
 pub fn from_path(path: &Path) -> EdResult<TextBuffer> {
diff --git a/examples/closure/.gitignore b/examples/closure/.gitignore
deleted file mode 100644
index 3b89e1b9f3..0000000000
--- a/examples/closure/.gitignore
+++ /dev/null
@@ -1 +0,0 @@
-closure
diff --git a/examples/closure/Closure.roc b/examples/closure/Closure.roc
deleted file mode 100644
index 03131b7dd1..0000000000
--- a/examples/closure/Closure.roc
+++ /dev/null
@@ -1,8 +0,0 @@
-app "closure" provides [ makeClosure ] to "./platform/"
-
-makeClosure : ({} -> Int *) as MyClosure
-makeClosure =
-    x = 42
-    y = 42
-
-    \{} -> x + y
diff --git a/examples/closure/platform/Cargo.lock b/examples/closure/platform/Cargo.lock
deleted file mode 100644
index c386bb6c4a..0000000000
--- a/examples/closure/platform/Cargo.lock
+++ /dev/null
@@ -1,23 +0,0 @@
-# This file is automatically @generated by Cargo.
-# It is not intended for manual editing.
-[[package]]
-name = "host"
-version = "0.1.0"
-dependencies = [
- "roc_std 0.1.0",
-]
-
-[[package]]
-name = "libc"
-version = "0.2.79"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-
-[[package]]
-name = "roc_std"
-version = "0.1.0"
-dependencies = [
- "libc 0.2.79 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
-[metadata]
-"checksum libc 0.2.79 (registry+https://github.com/rust-lang/crates.io-index)" = "2448f6066e80e3bfc792e9c98bf705b4b0fc6e8ef5b43e5889aff0eaa9c58743"
diff --git a/examples/closure/platform/Cargo.toml b/examples/closure/platform/Cargo.toml
deleted file mode 100644
index 70f3c1f86c..0000000000
--- a/examples/closure/platform/Cargo.toml
+++ /dev/null
@@ -1,13 +0,0 @@
-[package]
-name = "host"
-version = "0.1.0"
-authors = ["Richard Feldman <oss@rtfeldman.com>"]
-edition = "2018"
-
-[lib]
-crate-type = ["staticlib"]
-
-[dependencies]
-roc_std = { path = "../../../roc_std" }
-
-[workspace]
diff --git a/examples/closure/platform/Pkg-Config.roc b/examples/closure/platform/Pkg-Config.roc
deleted file mode 100644
index 8e351ef6ba..0000000000
--- a/examples/closure/platform/Pkg-Config.roc
+++ /dev/null
@@ -1,12 +0,0 @@
-platform examples/closure
-    requires { main : Effect {} }
-    exposes []
-    packages {}
-    imports []
-    provides [ mainForHost ]
-    effects Effect
-        {
-            putChar : Int -> Effect {},
-            putLine : Str -> Effect {},
-            getLine : Effect Str
-        }
diff --git a/examples/closure/platform/host.c b/examples/closure/platform/host.c
deleted file mode 100644
index 0378c69589..0000000000
--- a/examples/closure/platform/host.c
+++ /dev/null
@@ -1,7 +0,0 @@
-#include <stdio.h>
-
-extern int rust_main();
-
-int main() {
-  return rust_main();
-}
diff --git a/examples/closure/platform/src/lib.rs b/examples/closure/platform/src/lib.rs
deleted file mode 100644
index bbaca0733a..0000000000
--- a/examples/closure/platform/src/lib.rs
+++ /dev/null
@@ -1,95 +0,0 @@
-#![allow(non_snake_case)]
-
-use roc_std::alloca;
-use roc_std::RocCallResult;
-use std::alloc::Layout;
-use std::time::SystemTime;
-
-extern "C" {
-    #[link_name = "roc__makeClosure_1_exposed"]
-    fn make_closure(output: *mut u8) -> ();
-
-    #[link_name = "roc__makeClosure_1_size"]
-    fn closure_size() -> i64;
-
-    #[link_name = "roc__makeClosure_1_MyClosure_caller"]
-    fn call_MyClosure(function_pointer: *const u8, closure_data: *const u8, output: *mut u8) -> ();
-
-    #[link_name = "roc__makeClosure_1_MyClosure_size"]
-    fn size_MyClosure() -> i64;
-}
-
-unsafe fn call_the_closure(function_pointer: *const u8, closure_data_ptr: *const u8) -> i64 {
-    let size = size_MyClosure() as usize;
-
-    alloca::with_stack_bytes(size, |buffer| {
-        let buffer: *mut std::ffi::c_void = buffer;
-        let buffer: *mut u8 = buffer as *mut u8;
-
-        call_MyClosure(
-            function_pointer,
-            closure_data_ptr as *const u8,
-            buffer as *mut u8,
-        );
-
-        let output = &*(buffer as *mut RocCallResult<i64>);
-
-        match output.into() {
-            Ok(v) => v,
-            Err(e) => panic!("failed with {}", e),
-        }
-    })
-}
-
-#[no_mangle]
-pub fn rust_main() -> isize {
-    println!("Running Roc closure");
-    let start_time = SystemTime::now();
-
-    let size = unsafe { closure_size() } as usize;
-    let layout = Layout::array::<u8>(size).unwrap();
-    let answer = unsafe {
-        let buffer = std::alloc::alloc(layout);
-
-        make_closure(buffer);
-
-        let output = &*(buffer as *mut RocCallResult<()>);
-
-        match output.into() {
-            Ok(()) => {
-                let function_pointer = {
-                    // this is a pointer to the location where the function pointer is stored
-                    // we pass just the function pointer
-                    let temp = buffer.offset(8) as *const i64;
-
-                    (*temp) as *const u8
-                };
-
-                let closure_data_ptr = buffer.offset(16);
-
-                let result =
-                    call_the_closure(function_pointer as *const u8, closure_data_ptr as *const u8);
-
-                std::alloc::dealloc(buffer, layout);
-
-                result
-            }
-            Err(msg) => {
-                std::alloc::dealloc(buffer, layout);
-
-                panic!("Roc failed with message: {}", msg);
-            }
-        }
-    };
-    let end_time = SystemTime::now();
-    let duration = end_time.duration_since(start_time).unwrap();
-
-    println!(
-        "Roc closure took {:.4} ms to compute this answer: {:?}",
-        duration.as_secs_f64() * 1000.0,
-        answer
-    );
-
-    // Exit code
-    0
-}
diff --git a/examples/quicksort/platform/host.zig b/examples/quicksort/platform/host.zig
index e13fb26b76..bc5d13ce4a 100644
--- a/examples/quicksort/platform/host.zig
+++ b/examples/quicksort/platform/host.zig
@@ -22,6 +22,10 @@ pub export fn main() i32 {
     const stderr = std.io.getStdErr().writer();
 
     var raw_numbers: [NUM_NUMS + 1]i64 = undefined;
+
+    // set refcount to one
+    raw_numbers[0] = -9223372036854775808;
+
     var numbers = raw_numbers[1..];
 
     for (numbers) |x, i| {