Merge remote-tracking branch 'origin/trunk' into alias-nominal-equality

cli/src/repl/eval.rs

@@ -324,9 +324,9 @@ fn jit_to_ast_help<'a>(
                     todo!("print recursive tag unions in the REPL")
                 }
                 Content::Alias(_, _, _, actual) => {
-                    let content = env.subs.get_without_compacting(*actual).content;
+                    let content = env.subs.get_content_without_compacting(*actual);
 
-                    jit_to_ast_help(env, lib, main_fn_name, layout, &content)
+                    jit_to_ast_help(env, lib, main_fn_name, layout, content)
                 }
                 other => unreachable!("Weird content for Union layout: {:?}", other),
             }
@@ -468,7 +468,7 @@ fn list_to_ast<'a>(
 
             let elem_var = *vars.first().unwrap();
 
-            env.subs.get_without_compacting(elem_var).content
+            env.subs.get_content_without_compacting(elem_var)
         }
         other => {
             unreachable!(
@@ -486,7 +486,7 @@ fn list_to_ast<'a>(
         let offset_bytes = index * elem_size;
         let elem_ptr = unsafe { ptr.add(offset_bytes) };
         let loc_expr = &*arena.alloc(Located {
-            value: ptr_to_ast(env, elem_ptr, elem_layout, &elem_content),
+            value: ptr_to_ast(env, elem_ptr, elem_layout, elem_content),
             region: Region::zero(),
         });
 
@@ -539,8 +539,8 @@ where
     let mut field_ptr = ptr as *const u8;
 
     for (var, layout) in sequence {
-        let content = subs.get_without_compacting(var).content;
+        let content = subs.get_content_without_compacting(var);
-        let expr = ptr_to_ast(env, field_ptr, layout, &content);
+        let expr = ptr_to_ast(env, field_ptr, layout, content);
         let loc_expr = Located::at_zero(expr);
 
         output.push(&*arena.alloc(loc_expr));
@@ -577,10 +577,10 @@ fn struct_to_ast<'a>(
         // this is a 1-field wrapper record around another record or 1-tag tag union
         let (label, field) = sorted_fields.pop().unwrap();
 
-        let inner_content = env.subs.get_without_compacting(field.into_inner()).content;
+        let inner_content = env.subs.get_content_without_compacting(field.into_inner());
 
         let loc_expr = &*arena.alloc(Located {
-            value: ptr_to_ast(env, ptr, &Layout::Struct(field_layouts), &inner_content),
+            value: ptr_to_ast(env, ptr, &Layout::Struct(field_layouts), inner_content),
             region: Region::zero(),
         });
 
@@ -606,9 +606,9 @@ fn struct_to_ast<'a>(
         let mut field_ptr = ptr;
 
         for ((label, field), field_layout) in sorted_fields.iter().zip(field_layouts.iter()) {
-            let content = subs.get_without_compacting(*field.as_inner()).content;
+            let content = subs.get_content_without_compacting(*field.as_inner());
             let loc_expr = &*arena.alloc(Located {
-                value: ptr_to_ast(env, field_ptr, field_layout, &content),
+                value: ptr_to_ast(env, field_ptr, field_layout, content),
                 region: Region::zero(),
             });
 
@@ -659,9 +659,9 @@ fn bool_to_ast<'a>(env: &Env<'a, '_>, value: bool, content: &Content) -> Expr<'a
                         // and/or records (e.g. { a: { b: { c: True }  } }),
                         // so we need to do this recursively on the field type.
                         let field_var = *field.as_inner();
-                        let field_content = env.subs.get_without_compacting(field_var).content;
+                        let field_content = env.subs.get_content_without_compacting(field_var);
                         let loc_expr = Located {
-                            value: bool_to_ast(env, value, &field_content),
+                            value: bool_to_ast(env, value, field_content),
                             region: Region::zero(),
                         };
 
@@ -701,10 +701,10 @@ fn bool_to_ast<'a>(env: &Env<'a, '_>, value: bool, content: &Content) -> Expr<'a
                         debug_assert_eq!(payload_vars.len(), 1);
 
                         let var = *payload_vars.iter().next().unwrap();
-                        let content = env.subs.get_without_compacting(var).content;
+                        let content = env.subs.get_content_without_compacting(var);
 
                         let loc_payload = &*arena.alloc(Located {
-                            value: bool_to_ast(env, value, &content),
+                            value: bool_to_ast(env, value, content),
                             region: Region::zero(),
                         });
 
@@ -739,9 +739,9 @@ fn bool_to_ast<'a>(env: &Env<'a, '_>, value: bool, content: &Content) -> Expr<'a
             }
         }
         Alias(_, _, _, var) => {
-            let content = env.subs.get_without_compacting(*var).content;
+            let content = env.subs.get_content_without_compacting(*var);
 
-            bool_to_ast(env, value, &content)
+            bool_to_ast(env, value, content)
         }
         other => {
             unreachable!("Unexpected FlatType {:?} in bool_to_ast", other);
@@ -771,9 +771,9 @@ fn byte_to_ast<'a>(env: &Env<'a, '_>, value: u8, content: &Content) -> Expr<'a>
                         // and/or records (e.g. { a: { b: { c: True }  } }),
                         // so we need to do this recursively on the field type.
                         let field_var = *field.as_inner();
-                        let field_content = env.subs.get_without_compacting(field_var).content;
+                        let field_content = env.subs.get_content_without_compacting(field_var);
                         let loc_expr = Located {
-                            value: byte_to_ast(env, value, &field_content),
+                            value: byte_to_ast(env, value, field_content),
                             region: Region::zero(),
                         };
 
@@ -813,10 +813,10 @@ fn byte_to_ast<'a>(env: &Env<'a, '_>, value: u8, content: &Content) -> Expr<'a>
                         debug_assert_eq!(payload_vars.len(), 1);
 
                         let var = *payload_vars.iter().next().unwrap();
-                        let content = env.subs.get_without_compacting(var).content;
+                        let content = env.subs.get_content_without_compacting(var);
 
                         let loc_payload = &*arena.alloc(Located {
-                            value: byte_to_ast(env, value, &content),
+                            value: byte_to_ast(env, value, content),
                             region: Region::zero(),
                         });
 
@@ -850,9 +850,9 @@ fn byte_to_ast<'a>(env: &Env<'a, '_>, value: u8, content: &Content) -> Expr<'a>
             }
         }
         Alias(_, _, _, var) => {
-            let content = env.subs.get_without_compacting(*var).content;
+            let content = env.subs.get_content_without_compacting(*var);
 
-            byte_to_ast(env, value, &content)
+            byte_to_ast(env, value, content)
         }
         other => {
             unreachable!("Unexpected FlatType {:?} in bool_to_ast", other);
@@ -887,9 +887,9 @@ fn num_to_ast<'a>(env: &Env<'a, '_>, num_expr: Expr<'a>, content: &Content) -> E
                         // and/or records (e.g. { a: { b: { c: 5 }  } }),
                         // so we need to do this recursively on the field type.
                         let field_var = *field.as_inner();
-                        let field_content = env.subs.get_without_compacting(field_var).content;
+                        let field_content = env.subs.get_content_without_compacting(field_var);
                         let loc_expr = Located {
-                            value: num_to_ast(env, num_expr, &field_content),
+                            value: num_to_ast(env, num_expr, field_content),
                             region: Region::zero(),
                         };
 
@@ -937,10 +937,10 @@ fn num_to_ast<'a>(env: &Env<'a, '_>, num_expr: Expr<'a>, content: &Content) -> E
                         debug_assert_eq!(payload_vars.len(), 1);
 
                         let var = *payload_vars.iter().next().unwrap();
-                        let content = env.subs.get_without_compacting(var).content;
+                        let content = env.subs.get_content_without_compacting(var);
 
                         let loc_payload = &*arena.alloc(Located {
-                            value: num_to_ast(env, num_expr, &content),
+                            value: num_to_ast(env, num_expr, content),
                             region: Region::zero(),
                         });
 
@@ -955,9 +955,9 @@ fn num_to_ast<'a>(env: &Env<'a, '_>, num_expr: Expr<'a>, content: &Content) -> E
             }
         }
         Alias(_, _, _, var) => {
-            let content = env.subs.get_without_compacting(*var).content;
+            let content = env.subs.get_content_without_compacting(*var);
 
-            num_to_ast(env, num_expr, &content)
+            num_to_ast(env, num_expr, content)
         }
         other => {
             panic!("Unexpected FlatType {:?} in num_to_ast", other);

cli/src/repl/gen.rs

@@ -154,8 +154,8 @@ pub fn gen_and_eval<'a>(
 
         // pretty-print the expr type string for later.
         name_all_type_vars(main_fn_var, &mut subs);
-        let content = subs.get(main_fn_var).content;
+        let content = subs.get_content_without_compacting(main_fn_var);
-        let expr_type_str = content_to_string(content.clone(), &subs, home, &interns);
+        let expr_type_str = content_to_string(content, &subs, home, &interns);
 
         let (_, main_fn_layout) = match procedures.keys().find(|(s, _)| *s == main_fn_symbol) {
             Some(layout) => *layout,
@@ -227,7 +227,7 @@ pub fn gen_and_eval<'a>(
                 lib,
                 main_fn_name,
                 main_fn_layout,
-                &content,
+                content,
                 &env.interns,
                 home,
                 &subs,

compiler/load/tests/test_load.rs

@@ -184,10 +184,9 @@ mod test_load {
         expected_types: &mut HashMap<&str, &str>,
     ) {
         for (symbol, expr_var) in &def.pattern_vars {
-            let content = subs.get(*expr_var).content;
-
             name_all_type_vars(*expr_var, subs);
 
+            let content = subs.get_content_without_compacting(*expr_var);
             let actual_str = content_to_string(content, subs, home, interns);
             let fully_qualified = symbol.fully_qualified(interns, home).to_string();
             let expected_type = expected_types

compiler/mono/src/borrow.rs

@@ -21,20 +21,14 @@ pub fn infer_borrow<'a>(
     procs: &MutMap<(Symbol, ProcLayout<'a>), Proc<'a>>,
 ) -> ParamMap<'a> {
     // intern the layouts
-    let mut declaration_to_index = MutMap::with_capacity_and_hasher(procs.len(), default_hasher());
 
     let mut param_map = {
-        let mut i = 0;
+        let (declaration_to_index, total_number_of_params) = DeclarationToIndex::new(arena, procs);
-        for key in procs.keys() {
-            declaration_to_index.insert(*key, ParamOffset(i));
-
-            i += key.1.arguments.len();
-        }
 
         ParamMap {
             declaration_to_index,
             join_points: MutMap::default(),
-            declarations: bumpalo::vec![in arena; Param::EMPTY; i],
+            declarations: bumpalo::vec![in arena; Param::EMPTY; total_number_of_params],
         }
     };
 
@@ -118,7 +112,7 @@ pub fn infer_borrow<'a>(
 
             for (key, proc) in procs {
                 let symbol = key.0;
-                let offset = param_map.declaration_to_index[key];
+                let offset = param_map.get_param_offset(key.0, key.1);
 
                 // the component this symbol is a part of
                 let component = symbol_to_component[&symbol];
@@ -169,10 +163,71 @@ impl From<ParamOffset> for usize {
     }
 }
 
-#[derive(Debug, Clone)]
+#[derive(Debug)]
+struct DeclarationToIndex<'a> {
+    elements: Vec<'a, ((Symbol, ProcLayout<'a>), ParamOffset)>,
+}
+
+impl<'a> DeclarationToIndex<'a> {
+    fn new(arena: &'a Bump, procs: &MutMap<(Symbol, ProcLayout<'a>), Proc<'a>>) -> (Self, usize) {
+        let mut declaration_to_index = Vec::with_capacity_in(procs.len(), arena);
+
+        let mut i = 0;
+        for key in procs.keys().copied() {
+            declaration_to_index.push((key, ParamOffset(i)));
+
+            i += key.1.arguments.len();
+        }
+
+        declaration_to_index.sort_unstable_by_key(|t| t.0 .0);
+
+        (
+            DeclarationToIndex {
+                elements: declaration_to_index,
+            },
+            i,
+        )
+    }
+
+    fn get_param_offset(
+        &self,
+        needle_symbol: Symbol,
+        needle_layout: ProcLayout<'a>,
+    ) -> ParamOffset {
+        if let Ok(middle_index) = self
+            .elements
+            .binary_search_by_key(&needle_symbol, |t| t.0 .0)
+        {
+            // first, iterate backward until we hit a different symbol
+            let backward = self.elements[..middle_index].iter().rev();
+
+            for ((symbol, proc_layout), param_offset) in backward {
+                if *symbol != needle_symbol {
+                    break;
+                } else if *proc_layout == needle_layout {
+                    return *param_offset;
+                }
+            }
+
+            // if not found, iterate forward until we find our combo
+            let forward = self.elements[middle_index..].iter();
+
+            for ((symbol, proc_layout), param_offset) in forward {
+                if *symbol != needle_symbol {
+                    break;
+                } else if *proc_layout == needle_layout {
+                    return *param_offset;
+                }
+            }
+        }
+        unreachable!("symbol/layout combo must be in DeclarationToIndex")
+    }
+}
+
+#[derive(Debug)]
 pub struct ParamMap<'a> {
     /// Map a (Symbol, ProcLayout) pair to the starting index in the `declarations` array
-    declaration_to_index: MutMap<(Symbol, ProcLayout<'a>), ParamOffset>,
+    declaration_to_index: DeclarationToIndex<'a>,
     /// the parameters of all functions in a single flat array.
     ///
     /// - the map above gives the index of the first parameter for the function
@@ -184,11 +239,17 @@ pub struct ParamMap<'a> {
 }
 
 impl<'a> ParamMap<'a> {
+    pub fn get_param_offset(&self, symbol: Symbol, layout: ProcLayout<'a>) -> ParamOffset {
+        self.declaration_to_index.get_param_offset(symbol, layout)
+    }
+
     pub fn get_symbol(&self, symbol: Symbol, layout: ProcLayout<'a>) -> Option<&[Param<'a>]> {
-        let index: usize = self.declaration_to_index[&(symbol, layout)].into();
+        // let index: usize = self.declaration_to_index[&(symbol, layout)].into();
+        let index: usize = self.get_param_offset(symbol, layout).into();
 
         self.declarations.get(index..index + layout.arguments.len())
     }
+
     pub fn get_join_point(&self, id: JoinPointId) -> &'a [Param<'a>] {
         match self.join_points.get(&id) {
             Some(slice) => slice,
@@ -197,7 +258,7 @@ impl<'a> ParamMap<'a> {
     }
 
     pub fn iter_symbols(&'a self) -> impl Iterator<Item = &'a Symbol> {
-        self.declaration_to_index.iter().map(|t| &t.0 .0)
+        self.declaration_to_index.elements.iter().map(|t| &t.0 .0)
     }
 }
 
@@ -247,7 +308,7 @@ impl<'a> ParamMap<'a> {
             return;
         }
 
-        let index: usize = self.declaration_to_index[&key].into();
+        let index: usize = self.get_param_offset(key.0, key.1).into();
 
         for (i, param) in Self::init_borrow_args(arena, proc.args)
             .iter()
@@ -266,7 +327,7 @@ impl<'a> ParamMap<'a> {
         proc: &Proc<'a>,
         key: (Symbol, ProcLayout<'a>),
     ) {
-        let index: usize = self.declaration_to_index[&key].into();
+        let index: usize = self.get_param_offset(key.0, key.1).into();
 
         for (i, param) in Self::init_borrow_args_always_owned(arena, proc.args)
             .iter()

compiler/mono/src/ir.rs

@@ -3010,7 +3010,7 @@ pub fn with_hole<'a>(
             let arena = env.arena;
 
             debug_assert!(!matches!(
-                env.subs.get_without_compacting(variant_var).content,
+                env.subs.get_content_without_compacting(variant_var),
                 Content::Structure(FlatType::Func(_, _, _))
             ));
             convert_tag_union(
@@ -3035,12 +3035,15 @@ pub fn with_hole<'a>(
         } => {
             let arena = env.arena;
 
-            let desc = env.subs.get_without_compacting(variant_var);
+            let content = env.subs.get_content_without_compacting(variant_var);
+
+            if let Content::Structure(FlatType::Func(arg_vars, _, ret_var)) = content {
+                let ret_var = *ret_var;
+                let arg_vars = arg_vars.clone();
 
-            if let Content::Structure(FlatType::Func(arg_vars, _, ret_var)) = desc.content {
                 tag_union_to_function(
                     env,
-                    arg_vars,
+                    &arg_vars,
                     ret_var,
                     tag_name,
                     closure_name,
@@ -4343,7 +4346,7 @@ fn convert_tag_union<'a>(
 #[allow(clippy::too_many_arguments)]
 fn tag_union_to_function<'a>(
     env: &mut Env<'a, '_>,
-    argument_variables: std::vec::Vec<Variable>,
+    argument_variables: &[Variable],
     return_variable: Variable,
     tag_name: TagName,
     proc_symbol: Symbol,
@@ -4364,8 +4367,8 @@ fn tag_union_to_function<'a>(
 
         let loc_expr = Located::at_zero(roc_can::expr::Expr::Var(arg_symbol));
 
-        loc_pattern_args.push((arg_var, loc_pattern));
+        loc_pattern_args.push((*arg_var, loc_pattern));
-        loc_expr_args.push((arg_var, loc_expr));
+        loc_expr_args.push((*arg_var, loc_expr));
     }
 
     let loc_body = Located::at_zero(roc_can::expr::Expr::Tag {
@@ -7395,8 +7398,8 @@ fn from_can_pattern_help<'a>(
                         // TODO these don't match up in the uniqueness inference; when we remove
                         // that, reinstate this assert!
                         //
-                        // dbg!(&env.subs.get_without_compacting(*field_var).content);
+                        // dbg!(&env.subs.get_content_without_compacting(*field_var));
-                        // dbg!(&env.subs.get_without_compacting(destruct.value.var).content);
+                        // dbg!(&env.subs.get_content_without_compacting(destruct.var).content);
                         // debug_assert_eq!(
                         //     env.subs.get_root_key_without_compacting(*field_var),
                         //     env.subs.get_root_key_without_compacting(destruct.value.var)
@@ -7490,7 +7493,7 @@ pub fn num_argument_to_int_or_float(
     var: Variable,
     known_to_be_float: bool,
 ) -> IntOrFloat {
-    match subs.get_without_compacting(var).content {
+    match subs.get_content_without_compacting(var){
         Content::FlexVar(_) | Content::RigidVar(_) if known_to_be_float => IntOrFloat::BinaryFloatType(FloatPrecision::F64),
         Content::FlexVar(_) | Content::RigidVar(_) => IntOrFloat::SignedIntType(IntPrecision::I64), // We default (Num *) to I64
 

compiler/reporting/tests/helpers/mod.rs

@@ -36,7 +36,10 @@ pub fn infer_expr(
     };
     let (solved, _) = solve::run(&env, problems, subs, constraint);
 
-    let content = solved.inner().get_without_compacting(expr_var).content;
+    let content = solved
+        .inner()
+        .get_content_without_compacting(expr_var)
+        .clone();
 
     (content, solved.into_inner())
 }

compiler/solve/src/solve.rs

@@ -528,11 +528,10 @@ fn solve(
                                 .get(next_rank)
                                 .iter()
                                 .filter(|var| {
-                                    let current = subs.get_without_compacting(
+                                    let current_rank =
-                                        roc_types::subs::Variable::clone(var),
+                                        subs.get_rank(roc_types::subs::Variable::clone(var));
-                                    );
 
-                                    current.rank.into_usize() > next_rank.into_usize()
+                                    current_rank.into_usize() > next_rank.into_usize()
                                 })
                                 .collect::<Vec<_>>();
 
@@ -561,8 +560,7 @@ fn solve(
                         let failing: Vec<_> = rigid_vars
                             .iter()
                             .filter(|&var| {
-                                !subs.redundant(*var)
+                                !subs.redundant(*var) && subs.get_rank(*var) != Rank::NONE
-                                    && subs.get_without_compacting(*var).rank != Rank::NONE
                             })
                             .collect();
 

compiler/solve/tests/solve_expr.rs

@@ -115,7 +115,7 @@ mod solve_expr {
         let content = {
             debug_assert!(exposed_to_host.len() == 1);
             let (_symbol, variable) = exposed_to_host.into_iter().next().unwrap();
-            subs.get(variable).content
+            subs.get_content_without_compacting(variable)
         };
 
         let actual_str = content_to_string(content, subs, home, &interns);

compiler/types/src/pretty_print.rs

@@ -77,11 +77,11 @@ fn find_names_needed(
     use crate::subs::FlatType::*;
 
     while let Some((recursive, _chain)) = subs.occurs(variable) {
-        let content = subs.get_without_compacting(recursive).content;
+        let rec_var = subs.fresh_unnamed_flex_var();
+        let content = subs.get_content_without_compacting(recursive);
+
         match content {
             Content::Structure(FlatType::TagUnion(tags, ext_var)) => {
-                let rec_var = subs.fresh_unnamed_flex_var();
-
                 let mut new_tags = MutMap::default();
 
                 for (label, args) in tags {
@@ -94,7 +94,7 @@ fn find_names_needed(
                     new_tags.insert(label.clone(), new_args);
                 }
 
-                let flat_type = FlatType::RecursiveTagUnion(rec_var, new_tags, ext_var);
+                let flat_type = FlatType::RecursiveTagUnion(rec_var, new_tags, *ext_var);
                 subs.set_content(recursive, Content::Structure(flat_type));
             }
             _ => panic!(
@@ -104,7 +104,7 @@ fn find_names_needed(
         }
     }
 
-    match subs.get_without_compacting(variable).content {
+    match &subs.get_content_without_compacting(variable).clone() {
         RecursionVar { opt_name: None, .. } | FlexVar(None) => {
             let root = subs.get_root_key_without_compacting(variable);
 
@@ -133,24 +133,24 @@ fn find_names_needed(
 
             // User-defined names are already taken.
             // We must not accidentally generate names that collide with them!
-            names_taken.insert(name);
+            names_taken.insert(name.clone());
         }
         RigidVar(name) => {
             // User-defined names are already taken.
             // We must not accidentally generate names that collide with them!
-            names_taken.insert(name);
+            names_taken.insert(name.clone());
         }
         Structure(Apply(_, args)) => {
             for var in args {
-                find_names_needed(var, subs, roots, root_appearances, names_taken);
+                find_names_needed(*var, subs, roots, root_appearances, names_taken);
             }
         }
         Structure(Func(arg_vars, _closure_var, ret_var)) => {
             for var in arg_vars {
-                find_names_needed(var, subs, roots, root_appearances, names_taken);
+                find_names_needed(*var, subs, roots, root_appearances, names_taken);
             }
 
-            find_names_needed(ret_var, subs, roots, root_appearances, names_taken);
+            find_names_needed(*ret_var, subs, roots, root_appearances, names_taken);
         }
         Structure(Record(fields, ext_var)) => {
             let mut sorted_fields: Vec<_> = fields.iter().collect();
@@ -167,7 +167,7 @@ fn find_names_needed(
                 );
             }
 
-            find_names_needed(ext_var, subs, roots, root_appearances, names_taken);
+            find_names_needed(*ext_var, subs, roots, root_appearances, names_taken);
         }
         Structure(TagUnion(tags, ext_var)) => {
             let mut sorted_tags: Vec<_> = tags.iter().collect();
@@ -177,10 +177,10 @@ fn find_names_needed(
                 find_names_needed(*var, subs, roots, root_appearances, names_taken);
             }
 
-            find_names_needed(ext_var, subs, roots, root_appearances, names_taken);
+            find_names_needed(*ext_var, subs, roots, root_appearances, names_taken);
         }
         Structure(FunctionOrTagUnion(_, _, ext_var)) => {
-            find_names_needed(ext_var, subs, roots, root_appearances, names_taken);
+            find_names_needed(*ext_var, subs, roots, root_appearances, names_taken);
         }
         Structure(RecursiveTagUnion(rec_var, tags, ext_var)) => {
             let mut sorted_tags: Vec<_> = tags.iter().collect();
@@ -190,12 +190,12 @@ fn find_names_needed(
                 find_names_needed(*var, subs, roots, root_appearances, names_taken);
             }
 
-            find_names_needed(ext_var, subs, roots, root_appearances, names_taken);
+            find_names_needed(*ext_var, subs, roots, root_appearances, names_taken);
-            find_names_needed(rec_var, subs, roots, root_appearances, names_taken);
+            find_names_needed(*rec_var, subs, roots, root_appearances, names_taken);
         }
         Alias(_symbol, args, _, _actual) => {
             for (_, var) in args {
-                find_names_needed(var, subs, roots, root_appearances, names_taken);
+                find_names_needed(*var, subs, roots, root_appearances, names_taken);
             }
             // TODO should we also look in the actual variable?
             // find_names_needed(_actual, subs, roots, root_appearances, names_taken);
@@ -240,22 +240,22 @@ fn name_root(
 fn set_root_name(root: Variable, name: Lowercase, subs: &mut Subs) {
     use crate::subs::Content::*;
 
-    let mut descriptor = subs.get_without_compacting(root);
+    let old_content = subs.get_content_without_compacting(root);
 
-    match descriptor.content {
+    match old_content {
         FlexVar(None) => {
-            descriptor.content = FlexVar(Some(name));
+            let content = FlexVar(Some(name));
-            subs.set(root, descriptor);
+            subs.set_content(root, content);
         }
         RecursionVar {
             opt_name: None,
             structure,
         } => {
-            descriptor.content = RecursionVar {
+            let content = RecursionVar {
-                structure,
+                structure: *structure,
                 opt_name: Some(name),
             };
-            subs.set(root, descriptor);
+            subs.set_content(root, content);
         }
         RecursionVar {
             opt_name: Some(_existing),
@@ -270,7 +270,7 @@ fn set_root_name(root: Variable, name: Lowercase, subs: &mut Subs) {
 }
 
 pub fn content_to_string(
-    content: Content,
+    content: &Content,
     subs: &Subs,
     home: ModuleId,
     interns: &Interns,
@@ -283,7 +283,7 @@ pub fn content_to_string(
     buf
 }
 
-fn write_content(env: &Env, content: Content, subs: &Subs, buf: &mut String, parens: Parens) {
+fn write_content(env: &Env, content: &Content, subs: &Subs, buf: &mut String, parens: Parens) {
     use crate::subs::Content::*;
 
     match content {
@@ -298,14 +298,14 @@ fn write_content(env: &Env, content: Content, subs: &Subs, buf: &mut String, par
         Alias(symbol, args, _, _actual) => {
             let write_parens = parens == Parens::InTypeParam && !args.is_empty();
 
-            match symbol {
+            match *symbol {
                 Symbol::NUM_NUM => {
                     debug_assert_eq!(args.len(), 1);
 
                     let (_, arg_var) = args
                         .get(0)
                         .expect("Num was not applied to a type argument!");
-                    let content = subs.get_without_compacting(*arg_var).content;
+                    let content = subs.get_content_without_compacting(*arg_var);
 
                     match &content {
                         Alias(nested, _, _, _) => match *nested {
@@ -326,13 +326,13 @@ fn write_content(env: &Env, content: Content, subs: &Subs, buf: &mut String, par
                 }
 
                 _ => write_parens!(write_parens, buf, {
-                    write_symbol(env, symbol, buf);
+                    write_symbol(env, *symbol, buf);
 
                     for (_, var) in args {
                         buf.push(' ');
                         write_content(
                             env,
-                            subs.get_without_compacting(var).content,
+                            subs.get_content_without_compacting(*var),
                             subs,
                             buf,
                             Parens::InTypeParam,
@@ -342,7 +342,7 @@ fn write_content(env: &Env, content: Content, subs: &Subs, buf: &mut String, par
                     // useful for debugging
                     if false {
                         buf.push_str("[[ but really ");
-                        let content = subs.get_without_compacting(_actual).content;
+                        let content = subs.get_content_without_compacting(*_actual);
                         write_content(env, content, subs, buf, parens);
                         buf.push_str("]]");
                     }
@@ -353,19 +353,74 @@ fn write_content(env: &Env, content: Content, subs: &Subs, buf: &mut String, par
     }
 }
 
-fn write_flat_type(env: &Env, flat_type: FlatType, subs: &Subs, buf: &mut String, parens: Parens) {
+fn write_sorted_tags<'a>(
+    env: &Env,
+    subs: &'a Subs,
+    buf: &mut String,
+    tags: &MutMap<TagName, Vec<Variable>>,
+    ext_var: Variable,
+) -> Result<(), (Variable, &'a Content)> {
+    // Sort the fields so they always end up in the same order.
+    let mut sorted_fields = Vec::with_capacity(tags.len());
+
+    for (label, vars) in tags {
+        sorted_fields.push((label, vars));
+    }
+
+    // If the `ext` contains tags, merge them into the list of tags.
+    // this can occur when inferring mutually recursive tags
+    let mut from_ext = Default::default();
+    let ext_content = chase_ext_tag_union(subs, ext_var, &mut from_ext);
+
+    for (tag_name, arguments) in from_ext.iter() {
+        sorted_fields.push((tag_name, arguments));
+    }
+
+    let interns = &env.interns;
+    let home = env.home;
+
+    sorted_fields
+        .sort_by(|(a, _), (b, _)| a.as_string(interns, home).cmp(&b.as_string(interns, home)));
+
+    let mut any_written_yet = false;
+
+    for (label, vars) in sorted_fields {
+        if any_written_yet {
+            buf.push_str(", ");
+        } else {
+            any_written_yet = true;
+        }
+
+        buf.push_str(&label.as_string(interns, home));
+
+        for var in vars {
+            buf.push(' ');
+            write_content(
+                env,
+                subs.get_content_without_compacting(*var),
+                subs,
+                buf,
+                Parens::InTypeParam,
+            );
+        }
+    }
+
+    ext_content
+}
+
+fn write_flat_type(env: &Env, flat_type: &FlatType, subs: &Subs, buf: &mut String, parens: Parens) {
     use crate::subs::FlatType::*;
 
     match flat_type {
-        Apply(symbol, args) => write_apply(env, symbol, args, subs, buf, parens),
+        Apply(symbol, args) => write_apply(env, *symbol, args, subs, buf, parens),
         EmptyRecord => buf.push_str(EMPTY_RECORD),
         EmptyTagUnion => buf.push_str(EMPTY_TAG_UNION),
-        Func(args, _closure, ret) => write_fn(env, args, ret, subs, buf, parens),
+        Func(args, _closure, ret) => write_fn(env, args, *ret, subs, buf, parens),
         Record(fields, ext_var) => {
             use crate::types::{gather_fields, RecordStructure};
 
             // If the `ext` has concrete fields (e.g. { foo : I64}{ bar : Bool }), merge them
-            let RecordStructure { fields, ext } = gather_fields(subs, fields, ext_var);
+            let RecordStructure { fields, ext } = gather_fields(subs, fields, *ext_var);
             let ext_var = ext;
 
             if fields.is_empty() {
@@ -408,7 +463,7 @@ fn write_flat_type(env: &Env, flat_type: FlatType, subs: &Subs, buf: &mut String
 
                     write_content(
                         env,
-                        subs.get_without_compacting(var).content,
+                        subs.get_content_without_compacting(var),
                         subs,
                         buf,
                         Parens::Unnecessary,
@@ -418,7 +473,7 @@ fn write_flat_type(env: &Env, flat_type: FlatType, subs: &Subs, buf: &mut String
                 buf.push_str(" }");
             }
 
-            match subs.get_without_compacting(ext_var).content {
+            match subs.get_content_without_compacting(ext_var) {
                 Content::Structure(EmptyRecord) => {
                     // This is a closed record. We're done!
                 }
@@ -433,50 +488,9 @@ fn write_flat_type(env: &Env, flat_type: FlatType, subs: &Subs, buf: &mut String
             }
         }
         TagUnion(tags, ext_var) => {
-            let interns = &env.interns;
-            let home = env.home;
-
             buf.push_str("[ ");
 
-            // Sort the fields so they always end up in the same order.
+            let ext_content = write_sorted_tags(env, subs, buf, tags, *ext_var);
-            let mut sorted_fields = Vec::with_capacity(tags.len());
-
-            for (label, vars) in tags {
-                sorted_fields.push((label.clone(), vars));
-            }
-
-            // If the `ext` contains tags, merge them into the list of tags.
-            // this can occur when inferring mutually recursive tags
-            let ext_content = chase_ext_tag_union(subs, ext_var, &mut sorted_fields);
-
-            sorted_fields.sort_by(|(a, _), (b, _)| {
-                a.clone()
-                    .as_string(interns, home)
-                    .cmp(&b.as_string(interns, home))
-            });
-
-            let mut any_written_yet = false;
-
-            for (label, vars) in sorted_fields {
-                if any_written_yet {
-                    buf.push_str(", ");
-                } else {
-                    any_written_yet = true;
-                }
-
-                buf.push_str(&label.as_string(interns, home));
-
-                for var in vars {
-                    buf.push(' ');
-                    write_content(
-                        env,
-                        subs.get_without_compacting(var).content,
-                        subs,
-                        buf,
-                        Parens::InTypeParam,
-                    );
-                }
-            }
 
             buf.push_str(" ]");
 
@@ -491,17 +505,14 @@ fn write_flat_type(env: &Env, flat_type: FlatType, subs: &Subs, buf: &mut String
         }
 
         FunctionOrTagUnion(tag_name, _, ext_var) => {
-            let interns = &env.interns;
-            let home = env.home;
-
             buf.push_str("[ ");
 
-            buf.push_str(&tag_name.as_string(interns, home));
+            let mut tags = MutMap::default();
+            tags.insert(tag_name.clone(), vec![]);
+            let ext_content = write_sorted_tags(env, subs, buf, &tags, *ext_var);
 
             buf.push_str(" ]");
 
-            let mut sorted_fields = vec![(tag_name, vec![])];
-            let ext_content = chase_ext_tag_union(subs, ext_var, &mut sorted_fields);
             if let Err((_, content)) = ext_content {
                 // This is an open tag union, so print the variable
                 // right after the ']'
@@ -513,45 +524,9 @@ fn write_flat_type(env: &Env, flat_type: FlatType, subs: &Subs, buf: &mut String
         }
 
         RecursiveTagUnion(rec_var, tags, ext_var) => {
-            let interns = &env.interns;
-            let home = env.home;
-
             buf.push_str("[ ");
 
-            // Sort the fields so they always end up in the same order.
+            let ext_content = write_sorted_tags(env, subs, buf, tags, *ext_var);
-            let mut sorted_fields = Vec::with_capacity(tags.len());
-
-            for (label, vars) in tags {
-                sorted_fields.push((label.clone(), vars));
-            }
-
-            // If the `ext` contains tags, merge them into the list of tags.
-            // this can occur when inferring mutually recursive tags
-            let ext_content = chase_ext_tag_union(subs, ext_var, &mut sorted_fields);
-
-            sorted_fields.sort_by(|(a, _), (b, _)| a.cmp(b));
-
-            let mut any_written_yet = false;
-
-            for (label, vars) in sorted_fields {
-                if any_written_yet {
-                    buf.push_str(", ");
-                } else {
-                    any_written_yet = true;
-                }
-                buf.push_str(&label.as_string(interns, home));
-
-                for var in vars {
-                    buf.push(' ');
-                    write_content(
-                        env,
-                        subs.get_without_compacting(var).content,
-                        subs,
-                        buf,
-                        Parens::InTypeParam,
-                    );
-                }
-            }
 
             buf.push_str(" ]");
 
@@ -567,7 +542,7 @@ fn write_flat_type(env: &Env, flat_type: FlatType, subs: &Subs, buf: &mut String
             buf.push_str(" as ");
             write_content(
                 env,
-                subs.get_without_compacting(rec_var).content,
+                subs.get_content_without_compacting(*rec_var),
                 subs,
                 buf,
                 parens,
@@ -579,11 +554,11 @@ fn write_flat_type(env: &Env, flat_type: FlatType, subs: &Subs, buf: &mut String
     }
 }
 
-pub fn chase_ext_tag_union(
+pub fn chase_ext_tag_union<'a>(
-    subs: &Subs,
+    subs: &'a Subs,
     var: Variable,
     fields: &mut Vec<(TagName, Vec<Variable>)>,
-) -> Result<(), (Variable, Content)> {
+) -> Result<(), (Variable, &'a Content)> {
     use FlatType::*;
     match subs.get_content_without_compacting(var) {
         Content::Structure(EmptyTagUnion) => Ok(()),
@@ -602,7 +577,7 @@ pub fn chase_ext_tag_union(
         }
         Content::Alias(_, _, _, var) => chase_ext_tag_union(subs, *var, fields),
 
-        content => Err((var, content.clone())),
+        content => Err((var, content)),
     }
 }
 
@@ -614,25 +589,27 @@ pub fn chase_ext_record(
     use crate::subs::Content::*;
     use crate::subs::FlatType::*;
 
-    match subs.get_without_compacting(var).content {
+    match subs.get_content_without_compacting(var) {
         Structure(Record(sub_fields, sub_ext)) => {
-            fields.extend(sub_fields.into_iter());
+            for (field_name, record_field) in sub_fields {
+                fields.insert(field_name.clone(), *record_field);
+            }
 
-            chase_ext_record(subs, sub_ext, fields)
+            chase_ext_record(subs, *sub_ext, fields)
         }
 
         Structure(EmptyRecord) => Ok(()),
 
-        Alias(_, _, _, var) => chase_ext_record(subs, var, fields),
+        Alias(_, _, _, var) => chase_ext_record(subs, *var, fields),
 
-        content => Err((var, content)),
+        content => Err((var, content.clone())),
     }
 }
 
 fn write_apply(
     env: &Env,
     symbol: Symbol,
-    args: Vec<Variable>,
+    args: &[Variable],
     subs: &Subs,
     buf: &mut String,
     parens: Parens,
@@ -646,10 +623,10 @@ fn write_apply(
         }
         Symbol::NUM_NUM => {
             let arg = args
-                .into_iter()
+                .iter()
                 .next()
                 .unwrap_or_else(|| panic!("Num did not have any type parameters somehow."));
-            let arg_content = subs.get_without_compacting(arg).content;
+            let arg_content = subs.get_content_without_compacting(*arg);
             let mut arg_param = String::new();
 
             let mut default_case = |subs, content| {
@@ -690,7 +667,7 @@ fn write_apply(
                 buf.push(' ');
                 write_content(
                     env,
-                    subs.get_without_compacting(arg).content,
+                    subs.get_content_without_compacting(*arg),
                     subs,
                     buf,
                     Parens::InTypeParam,
@@ -706,7 +683,7 @@ fn write_apply(
 
 fn write_fn(
     env: &Env,
-    args: Vec<Variable>,
+    args: &[Variable],
     ret: Variable,
     subs: &Subs,
     buf: &mut String,
@@ -728,7 +705,7 @@ fn write_fn(
 
         write_content(
             env,
-            subs.get_without_compacting(arg).content,
+            subs.get_content_without_compacting(*arg),
             subs,
             buf,
             Parens::InFn,
@@ -738,7 +715,7 @@ fn write_fn(
     buf.push_str(" -> ");
     write_content(
         env,
-        subs.get_without_compacting(ret).content,
+        subs.get_content_without_compacting(ret),
         subs,
         buf,
         Parens::InFn,

compiler/types/src/subs.rs

@@ -990,7 +990,7 @@ impl Content {
 
         eprintln!(
             "{}",
-            crate::pretty_print::content_to_string(self.clone(), subs, home, &interns)
+            crate::pretty_print::content_to_string(&self, subs, home, &interns)
         );
 
         self
@@ -1031,7 +1031,7 @@ fn occurs(
     if seen.contains(&root_var) {
         Some((root_var, vec![]))
     } else {
-        match subs.get_without_compacting(root_var).content {
+        match subs.get_content_without_compacting(root_var) {
             FlexVar(_) | RigidVar(_) | RecursionVar { .. } | Error => None,
 
             Structure(flat_type) => {
@@ -1042,14 +1042,14 @@ fn occurs(
                 match flat_type {
                     Apply(_, args) => short_circuit(subs, root_var, &new_seen, args.iter()),
                     Func(arg_vars, closure_var, ret_var) => {
-                        let it = once(&ret_var)
+                        let it = once(ret_var)
-                            .chain(once(&closure_var))
+                            .chain(once(closure_var))
                             .chain(arg_vars.iter());
                         short_circuit(subs, root_var, &new_seen, it)
                     }
                     Record(vars_by_field, ext_var) => {
                         let it =
-                            once(&ext_var).chain(vars_by_field.values().map(|field| match field {
+                            once(ext_var).chain(vars_by_field.values().map(|field| match field {
                                 RecordField::Optional(var) => var,
                                 RecordField::Required(var) => var,
                                 RecordField::Demanded(var) => var,
@@ -1057,22 +1057,22 @@ fn occurs(
                         short_circuit(subs, root_var, &new_seen, it)
                     }
                     TagUnion(tags, ext_var) => {
-                        let it = once(&ext_var).chain(tags.values().flatten());
+                        let it = once(ext_var).chain(tags.values().flatten());
                         short_circuit(subs, root_var, &new_seen, it)
                     }
                     FunctionOrTagUnion(_, _, ext_var) => {
-                        let it = once(&ext_var);
+                        let it = once(ext_var);
                         short_circuit(subs, root_var, &new_seen, it)
                     }
                     RecursiveTagUnion(_rec_var, tags, ext_var) => {
                         // TODO rec_var is excluded here, verify that this is correct
-                        let it = once(&ext_var).chain(tags.values().flatten());
+                        let it = once(ext_var).chain(tags.values().flatten());
                         short_circuit(subs, root_var, &new_seen, it)
                     }
                     EmptyRecord | EmptyTagUnion | Erroneous(_) => None,
                 }
             }
-            Alias(symbol, type_arguments, lambda_set_variables, _) => {
+            Alias(_, type_arguments, lambda_set_variables, _) => {
                 let mut new_seen = seen.clone();
                 new_seen.insert(root_var);
 

compiler/types/src/types.rs

@@ -1,7 +1,7 @@
 use crate::pretty_print::Parens;
 use crate::subs::{Subs, VarStore, Variable};
 use inlinable_string::InlinableString;
-use roc_collections::all::{union, ImMap, ImSet, Index, MutMap, MutSet, SendMap};
+use roc_collections::all::{ImMap, ImSet, Index, MutMap, MutSet, SendMap};
 use roc_module::ident::{ForeignSymbol, Ident, Lowercase, TagName};
 use roc_module::low_level::LowLevel;
 use roc_module::symbol::{Interns, ModuleId, Symbol};
@@ -1595,22 +1595,35 @@ pub fn name_type_var(letters_used: u32, taken: &mut MutSet<Lowercase>) -> (Lower
 
 pub fn gather_fields(
     subs: &Subs,
-    fields: MutMap<Lowercase, RecordField<Variable>>,
+    other_fields: &MutMap<Lowercase, RecordField<Variable>>,
-    var: Variable,
+    mut var: Variable,
 ) -> RecordStructure {
     use crate::subs::Content::*;
     use crate::subs::FlatType::*;
 
-    match subs.get_without_compacting(var).content {
+    let mut result = other_fields.clone();
-        Structure(Record(sub_fields, sub_ext)) => {
-            gather_fields(subs, union(fields, &sub_fields), sub_ext)
-        }
 
-        Alias(_, _, _, var) => {
+    loop {
-            // TODO according to elm/compiler: "TODO may be dropping useful alias info here"
+        match subs.get_content_without_compacting(var) {
-            gather_fields(subs, fields, var)
+            Structure(Record(sub_fields, sub_ext)) => {
-        }
+                for (lowercase, record_field) in sub_fields {
+                    result.insert(lowercase.clone(), *record_field);
+                }
 
-        _ => RecordStructure { fields, ext: var },
+                var = *sub_ext;
+            }
+
+            Alias(_, _, _, actual_var) => {
+                // TODO according to elm/compiler: "TODO may be dropping useful alias info here"
+                var = *actual_var;
+            }
+
+            _ => break,
+        }
+    }
+
+    RecordStructure {
+        fields: result,
+        ext: var,
     }
 }

compiler/unify/src/unify.rs

@@ -995,8 +995,8 @@ fn unify_flat_type(
         }
 
         (Record(fields1, ext1), Record(fields2, ext2)) => {
-            let rec1 = gather_fields(subs, fields1.clone(), *ext1);
+            let rec1 = gather_fields(subs, fields1, *ext1);
-            let rec2 = gather_fields(subs, fields2.clone(), *ext2);
+            let rec2 = gather_fields(subs, fields2, *ext2);
 
             unify_record(subs, pool, ctx, rec1, rec2)
         }

editor/src/editor/mvc/ed_update.rs

@@ -272,7 +272,7 @@ impl<'a> EdModel<'a> {
 
         let subs = solved.inner_mut();
 
-        let content = subs.get(var).content;
+        let content = subs.get_content_without_compacting(var);
 
         PoolStr::new(
             &content_to_string(content, subs, self.module.env.home, self.interns),

editor/src/lang/constrain.rs

@@ -57,7 +57,7 @@ pub fn constrain_expr<'a>(
         Expr2::Blank => True,
         Expr2::EmptyRecord => constrain_empty_record(expected, region),
         Expr2::Var(symbol) => Lookup(*symbol, expected, region),
-        Expr2::SmallInt { var, .. } => {
+        Expr2::SmallInt { var, .. } | Expr2::I128 { var, .. } | Expr2::U128 { var, .. } => {
             let mut flex_vars = BumpVec::with_capacity_in(1, arena);
 
             flex_vars.push(*var);
@@ -910,7 +910,57 @@ pub fn constrain_expr<'a>(
 
             exists(arena, flex_vars, And(cons))
         }
-        _ => todo!("implement constraints for {:?}", expr),
+
+        Expr2::RunLowLevel { op, args, ret_var } => {
+            // This is a modified version of what we do for function calls.
+
+            // The operation's return type
+            let ret_type = Type2::Variable(*ret_var);
+
+            // This will be used in the occurs check
+            let mut vars = BumpVec::with_capacity_in(1 + args.len(), arena);
+
+            vars.push(*ret_var);
+
+            let mut arg_types = BumpVec::with_capacity_in(args.len(), arena);
+            let mut arg_cons = BumpVec::with_capacity_in(args.len(), arena);
+
+            for (index, node_id) in args.iter_node_ids().enumerate() {
+                let (arg_var, arg_id) = env.pool.get(node_id);
+
+                vars.push(*arg_var);
+
+                let arg_type = Type2::Variable(*arg_var);
+
+                let reason = Reason::LowLevelOpArg {
+                    op: *op,
+                    arg_index: Index::zero_based(index),
+                };
+                let expected_arg =
+                    Expected::ForReason(reason, arg_type.shallow_clone(), Region::zero());
+                let arg = env.pool.get(*arg_id);
+
+                let arg_con = constrain_expr(arena, env, arg, expected_arg, Region::zero());
+
+                arg_types.push(arg_type);
+                arg_cons.push(arg_con);
+            }
+
+            let category = Category::LowLevelOpResult(*op);
+
+            let mut and_constraints = BumpVec::with_capacity_in(2, arena);
+
+            and_constraints.push(And(arg_cons));
+            and_constraints.push(Eq(ret_type, expected, category, region));
+
+            exists(arena, vars, And(and_constraints))
+        }
+        Expr2::RuntimeError() => True,
+        Expr2::Closure { .. } => todo!(),
+        Expr2::PrivateTag { .. } => todo!(),
+        Expr2::InvalidLookup(_) => todo!(),
+        Expr2::LetRec { .. } => todo!(),
+        Expr2::LetFunction { .. } => todo!(),
     }
 }
 

editor/src/lang/solve.rs

@@ -565,11 +565,10 @@ fn solve<'a>(
                                 .get(next_rank)
                                 .iter()
                                 .filter(|var| {
-                                    let current = subs.get_without_compacting(
+                                    let current_rank =
-                                        roc_types::subs::Variable::clone(var),
+                                        subs.get_rank(roc_types::subs::Variable::clone(var));
-                                    );
 
-                                    current.rank.into_usize() > next_rank.into_usize()
+                                    current_rank.into_usize() > next_rank.into_usize()
                                 })
                                 .collect::<Vec<_>>();
 
@@ -598,8 +597,7 @@ fn solve<'a>(
                         let failing: Vec<_> = rigid_vars
                             .iter()
                             .filter(|&var| {
-                                !subs.redundant(*var)
+                                !subs.redundant(*var) && subs.get_rank(*var) != Rank::NONE
-                                    && subs.get_without_compacting(*var).rank != Rank::NONE
                             })
                             .collect();
 

editor/tests/solve_expr2.rs

@@ -114,7 +114,7 @@ fn infer_eq(actual: &str, expected_str: &str) {
 
             let subs = solved.inner_mut();
 
-            let content = subs.get(var).content;
+            let content = subs.get_content_without_compacting(var);
 
             let interns = Interns {
                 module_ids: env.module_ids.clone(),
@@ -328,3 +328,16 @@ fn constrain_update() {
         "{ name : Str }",
     )
 }
+
+#[ignore = "TODO: implement builtins in the editor"]
+#[test]
+fn constrain_run_low_level() {
+    infer_eq(
+        indoc!(
+            r#"
+            List.map [ { name: "roc" }, { name: "bird" } ] .name
+            "#
+        ),
+        "List Str",
+    )
+}