bring parse errors into the reporting tests

compiler/parse/src/expr.rs

@@ -1247,7 +1247,11 @@ pub fn ident_etc<'a>(min_indent: u16) -> impl Parser<'a, Expr<'a>> {
                 (Some(_loc_args), Some((_spaces_before_equals, Either::First(_equals_indent)))) => {
                     // We got args with an '=' after them, e.g. `foo a b = ...`
                     // This is a syntax error!
-                    panic!("TODO gracefully handle parse error for defs like `foo a b = ...`");
+                    let fail = Fail {
+                        attempting: state.attempting,
+                        reason: FailReason::ArgumentsBeforeEquals,
+                    };
+                    Err((fail, state))
                 }
                 (None, Some((spaces_before_equals, Either::First(equals_indent)))) => {
                     // We got '=' with no args before it

compiler/parse/src/parser.rs

@@ -190,6 +190,7 @@ pub enum FailReason {
     Eof(Region),
     InvalidPattern,
     ReservedKeyword(Region),
+    ArgumentsBeforeEquals,
 }
 
 #[derive(Debug, Clone, PartialEq, Eq)]

compiler/reporting/tests/helpers/mod.rs

@@ -103,96 +103,10 @@ pub fn parse_loc_with<'a>(arena: &'a Bump, input: &'a str) -> Result<Located<ast
 }
 
 #[allow(dead_code)]
-pub fn can_expr(expr_str: &str) -> CanExprOut {
+pub fn can_expr(expr_str: &str) -> Result<CanExprOut, Fail> {
     can_expr_with(&Bump::new(), test_home(), expr_str)
 }
 
-#[allow(dead_code)]
-pub fn uniq_expr(
-    expr_str: &str,
-) -> (
-    Located<Expr>,
-    Output,
-    Vec<Problem>,
-    Subs,
-    Variable,
-    Constraint,
-    ModuleId,
-    Interns,
-) {
-    let declared_idents: &ImMap<Ident, (Symbol, Region)> = &ImMap::default();
-
-    uniq_expr_with(&Bump::new(), expr_str, declared_idents)
-}
-
-#[allow(dead_code)]
-pub fn uniq_expr_with(
-    arena: &Bump,
-    expr_str: &str,
-    declared_idents: &ImMap<Ident, (Symbol, Region)>,
-) -> (
-    Located<Expr>,
-    Output,
-    Vec<Problem>,
-    Subs,
-    Variable,
-    Constraint,
-    ModuleId,
-    Interns,
-) {
-    let home = test_home();
-    let CanExprOut {
-        loc_expr,
-        output,
-        problems,
-        var_store: old_var_store,
-        var,
-        interns,
-        ..
-    } = can_expr_with(arena, home, expr_str);
-
-    // double check
-    let var_store = VarStore::new(old_var_store.fresh());
-
-    let expected2 = Expected::NoExpectation(Type::Variable(var));
-    let constraint = roc_constrain::uniq::constrain_declaration(
-        home,
-        &var_store,
-        Region::zero(),
-        &loc_expr,
-        declared_idents,
-        expected2,
-    );
-
-    let stdlib = uniq_stdlib();
-
-    let types = stdlib.types;
-    let imports: Vec<_> = types
-        .iter()
-        .map(|(symbol, (solved_type, region))| Import {
-            loc_symbol: Located::at(*region, *symbol),
-            solved_type: solved_type,
-        })
-        .collect();
-
-    // load builtin values
-
-    // TODO what to do with those rigids?
-    let (_introduced_rigids, constraint) =
-        constrain_imported_values(imports, constraint, &var_store);
-
-    // load builtin types
-    let mut constraint = load_builtin_aliases(&stdlib.aliases, constraint, &var_store);
-
-    constraint.instantiate_aliases(&var_store);
-
-    let subs2 = Subs::new(var_store.into());
-
-    (
-        loc_expr, output, problems, subs2, var, constraint, home, interns,
-    )
-}
-
 pub struct CanExprOut {
     pub loc_expr: Located<Expr>,
     pub output: Output,
@@ -205,13 +119,13 @@ pub struct CanExprOut {
 }
 
 #[allow(dead_code)]
-pub fn can_expr_with(arena: &Bump, home: ModuleId, expr_str: &str) -> CanExprOut {
-    let loc_expr = parse_loc_with(&arena, expr_str).unwrap_or_else(|e| {
-        panic!(
-            "can_expr_with() got a parse error when attempting to canonicalize:\n\n{:?} {:?}",
-            expr_str, e
-        )
-    });
+pub fn can_expr_with(arena: &Bump, home: ModuleId, expr_str: &str) -> Result<CanExprOut, Fail> {
+    let loc_expr = match parse_loc_with(&arena, expr_str) {
+        Ok(e) => e,
+        Err(fail) => {
+            return Err(fail);
+        }
+    };
 
     let var_store = VarStore::default();
     let var = var_store.fresh();
@@ -283,7 +197,7 @@ pub fn can_expr_with(arena: &Bump, home: ModuleId, expr_str: &str) -> CanExprOut
         all_ident_ids,
     };
 
-    CanExprOut {
+    Ok(CanExprOut {
         loc_expr,
         output,
         problems: env.problems,
@@ -292,7 +206,7 @@ pub fn can_expr_with(arena: &Bump, home: ModuleId, expr_str: &str) -> CanExprOut
         interns,
         var,
         constraint,
-    }
+    })
 }
 
 #[allow(dead_code)]

compiler/reporting/tests/test_reporting.rs

@@ -23,6 +23,7 @@ mod test_reporting {
     use std::path::PathBuf;
     // use roc_region::all;
     use crate::helpers::{can_expr, infer_expr, CanExprOut};
+    use roc_parse::parser::Fail;
     use roc_reporting::report::{RocDocAllocator, RocDocBuilder};
     use roc_solve::solve;
 
@@ -43,13 +44,16 @@ mod test_reporting {
 
     fn infer_expr_help(
         expr_src: &str,
-    ) -> (
+    ) -> Result<
+        (
             Vec<solve::TypeError>,
             Vec<roc_problem::can::Problem>,
             Vec<roc_mono::expr::MonoProblem>,
             ModuleId,
             Interns,
-    ) {
+        ),
+        Fail,
+    > {
         let CanExprOut {
             loc_expr,
             output,
@@ -60,7 +64,7 @@ mod test_reporting {
             mut interns,
             problems: can_problems,
             ..
-        } = can_expr(expr_src);
+        } = can_expr(expr_src)?;
         let mut subs = Subs::new(var_store.into());
 
         for (var, name) in output.introduced_variables.name_by_var {
@@ -99,7 +103,7 @@ mod test_reporting {
             );
         }
 
-        (unify_problems, can_problems, mono_problems, home, interns)
+        Ok((unify_problems, can_problems, mono_problems, home, interns))
     }
 
     fn list_reports<F>(src: &str, buf: &mut String, callback: F)
@@ -108,8 +112,9 @@ mod test_reporting {
     {
         use ven_pretty::DocAllocator;
 
-        let (type_problems, can_problems, mono_problems, home, interns) = infer_expr_help(src);
-
+        match infer_expr_help(src) {
+            Err(fail) => todo!(),
+            Ok((type_problems, can_problems, mono_problems, home, interns)) => {
                 let src_lines: Vec<&str> = src.split('\n').collect();
                 let alloc = RocDocAllocator::new(&src_lines, home, &interns);
 
@@ -143,6 +148,8 @@ mod test_reporting {
 
                 callback(doc, buf)
             }
+        }
+    }
 
     fn report_problem_as(src: &str, expected_rendering: &str) {
         let mut buf: String = String::new();
@@ -491,7 +498,8 @@ mod test_reporting {
             "#
         );
 
-        let (_type_problems, _can_problems, _mono_problems, home, interns) = infer_expr_help(src);
+        let (_type_problems, _can_problems, _mono_problems, home, interns) =
+            infer_expr_help(src).expect("parse error");
 
         let mut buf = String::new();
         let src_lines: Vec<&str> = src.split('\n').collect();
@@ -521,7 +529,7 @@ mod test_reporting {
         );
 
         let (_type_problems, _can_problems, _mono_problems, home, mut interns) =
-            infer_expr_help(src);
+            infer_expr_help(src).expect("parse error");
 
         let mut buf = String::new();
         let src_lines: Vec<&str> = src.split('\n').collect();
@@ -2671,4 +2679,30 @@ mod test_reporting {
             ),
         )
     }
+
+    #[test]
+    fn elm_function_syntax() {
+        report_problem_as(
+            indoc!(
+                r#"
+                f x y = x
+                "#
+            ),
+            indoc!(
+                r#"
+                -- SYNTAX PROBLEM --------------------------------------------------------------
+
+                The `a` type variable is not used in the `Foo` alias definition:
+
+                1 ┆  Foo a : [ Foo ]
+                  ┆      ^
+
+                Roc does not allow unused type parameters!
+
+                Hint: If you want an unused type parameter (a so-called "phantom
+                type"), read the guide section on phantom data.
+                "#
+            ),
+        )
+    }
 }