fix(compiler): Correct error message for unbound type variables (#1327)

grain-lang · Jun 13, 2022 · 762362a · 762362a
1 parent 75bbb93
commit 762362a
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Showing 2 changed files with 14 additions and 1 deletion.
diff --git a/compiler/src/typed/typetexp.re b/compiler/src/typed/typetexp.re
@@ -457,7 +457,13 @@ let globalize_used_variables = (env, fixed) => {
  try(r := [(loc, v, Tbl.find(name, type_variables^)), ...r^]) {
  | Not_found =>
  if (fixed && Btype.is_Tvar(repr(ty))) {
- raise(Error(loc, env, Unbound_type_variable("'" ++ name)));
+ raise(
+ Error(
+ loc,
+ env,
+ Unbound_type_variable(Printf.sprintf("'%s'", name)),
+ ),
+ );
  };
  let v2 = new_global_var();
  r := [(loc, v, v2), ...r^];

diff --git a/compiler/test/suites/types.re b/compiler/test/suites/types.re
@@ -110,6 +110,13 @@ describe("aliased types", ({test, testSkip}) => {
  |},
  "Type String is not compatible with type Number",
  );
+ assertCompileError(
+ "err_type_alias_5",
+ {|
+ type Foo = List<a>
+ |},
+ "Unbound type parameter 'a'",
+ );
  assertRun(
  "import_type_alias_1",
  {|