Add unexpected fn params test case

crates/cli/tests/cli_run.rs

@@ -771,14 +771,14 @@ mod cli_run {
 
     #[test]
     #[cfg_attr(windows, ignore)]
-    fn module_params_remove_from_errors() {
+    fn module_params_arity_mismatch() {
         check_compile_error_with(
             CMD_DEV,
-            &cli_testing_dir("/module_params/bad_types.roc"),
+            &cli_testing_dir("/module_params/arity_mismatch.roc"),
             &[],
             indoc!(
                 r#"
-                ── TOO MANY ARGS in tests/module_params/bad_types.roc ──────────────────────────
+                ── TOO MANY ARGS in tests/module_params/arity_mismatch.roc ─────────────────────
 
                 The getUser function expects 1 argument, but it got 2 instead:
 
@@ -788,7 +788,7 @@ mod cli_run {
                 Are there any missing commas? Or missing parentheses?
 
 
-                ── TOO MANY ARGS in tests/module_params/bad_types.roc ──────────────────────────
+                ── TOO MANY ARGS in tests/module_params/arity_mismatch.roc ─────────────────────
 
                 This value is not a function, but it was given 1 argument:
 
@@ -798,7 +798,7 @@ mod cli_run {
                 Are there any missing commas? Or missing parentheses?
 
 
-                ── TOO FEW ARGS in tests/module_params/bad_types.roc ───────────────────────────
+                ── TOO FEW ARGS in tests/module_params/arity_mismatch.roc ──────────────────────
 
                 The getPostComment function expects 2 arguments, but it got only 1:
 
@@ -815,6 +815,37 @@ mod cli_run {
         );
     }
 
+    #[test]
+    #[cfg_attr(windows, ignore)]
+    fn module_params_unexpected_fn() {
+        check_compile_error_with(
+            CMD_DEV,
+            &cli_testing_dir("/module_params/unexpected_fn.roc"),
+            &[],
+            indoc!(
+                r#"
+                ── TYPE MISMATCH in tests/module_params/unexpected_fn.roc ──────────────────────
+
+                This argument to this string interpolation has an unexpected type:
+
+                11│      $(Api.getPost)
+                           ^^^^^^^^^^^
+
+                The argument is an anonymous function of type:
+
+                    U32 -> Str
+
+                But this string interpolation needs its argument to be:
+
+                    Str
+
+                ────────────────────────────────────────────────────────────────────────────────
+
+                1 error and 0 warnings found in <ignored for test> ms."#
+            ),
+        )
+    }
+
     #[test]
     #[cfg_attr(windows, ignore)]
     fn transitive_expects() {

crates/cli/tests/module_params/unexpected_fn.roc

@@ -0,0 +1,12 @@
+app [main] {
+    pf: platform "../fixtures/multi-dep-str/platform/main.roc",
+}
+
+import Api { appId: "one", protocol: https }
+
+https = \url -> "https://$(url)"
+
+main =
+    """
+    $(Api.getPost)
+    """

crates/compiler/lower_params/src/type_error.rs

@@ -91,26 +91,26 @@ fn remove_with_bad_expr_reason(
             name: Some(name),
             arity,
             called_via: _,
-        } => {
-            if env.is_extended(name) {
-                debug_assert_ne!(0, *arity);
+        } if env.is_extended(name) => {
+            *arity -= 1;
+            debug_assert_ne!(0, *arity);
 
-                *arity -= 1;
-                drop_last_argument(found_type);
-                drop_last_argument(expected_type);
-            }
+            drop_last_argument(found_type);
+            drop_last_argument(expected_type);
         }
 
         Reason::FnCall { .. } => {}
 
         Reason::FnArg {
-            name: _,
+            name: Some(name),
             arg_index: _,
             called_via: _,
-        } => {
-            todo!();
+        } if env.is_extended(name) => {
+            todo!()
         }
 
+        Reason::FnArg { .. } => {}
+
         // Irrelevant
         Reason::TypedArg {
             name: _,