test for record diff

compiler/constrain/src/expr.rs

@@ -238,8 +238,9 @@ pub fn constrain_expr(
             let fn_type = Variable(*fn_var);
             let fn_region = loc_fn.region;
             let fn_expected = NoExpectation(fn_type.clone());
-            // TODO look up the name and use NamedFnArg if possible.
-            let fn_reason = Reason::AnonymousFnCall {
+
+            let fn_reason = Reason::FnCall {
+                name: opt_symbol,
                 arity: loc_args.len() as u8,
             };
 
@@ -260,8 +261,9 @@ pub fn constrain_expr(
             for (index, (arg_var, loc_arg)) in loc_args.iter().enumerate() {
                 let region = loc_arg.region;
                 let arg_type = Variable(*arg_var);
-                // TODO look up the name and use NamedFnArg if possible.
-                let reason = Reason::AnonymousFnArg {
+
+                let reason = Reason::FnArg {
+                    name: opt_symbol,
                     arg_index: index as u8,
                 };
                 let expected_arg = ForReason(reason, arg_type.clone(), region);

compiler/constrain/src/uniq.rs

@@ -741,8 +741,8 @@ pub fn constrain_expr(
                 fn_expected,
             );
 
-            // TODO look up the name and use NamedFnArg if possible.
-            let fn_reason = Reason::AnonymousFnCall {
+            let fn_reason = Reason::FnCall {
+                name: opt_symbol,
                 arity: loc_args.len() as u8,
             };
 
@@ -753,7 +753,8 @@ pub fn constrain_expr(
                 let region = loc_arg.region;
                 let arg_type = Variable(*arg_var);
 
-                let reason = Reason::AnonymousFnArg {
+                let reason = Reason::FnArg {
+                    name: opt_symbol,
                     arg_index: index as u8,
                 };
 

compiler/reporting/src/type_error.rs

@@ -252,7 +252,6 @@ fn to_expr_report(
             },
             Reason::WhenBranch { index } => {
                 // NOTE: is 0-based
-
                 let ith = int_to_ordinal(index + 1);
 
                 report_mismatch(
@@ -297,7 +296,7 @@ fn to_expr_report(
                     plain_text("I need all elements of a list to have the same type!"),
                 )
             }
-            Reason::RecordUpdateValue(field) => report_mismatch(
+            Reason::RecordUpdateValue(field) => { report_mismatch(
                 filename,
                 &category,
                 found,
@@ -316,9 +315,31 @@ fn to_expr_report(
                 ]),
                 plain_text("But it should be:"),
                 plain_text("Record update syntax does not allow you to change the type of fields. You can achieve that with record literal syntax."),
-            ),
+            )}
+            Reason::FnArg { name , arg_index } => { 
+                let ith = int_to_ordinal(arg_index as usize + 1);
+
+                let this_function = match name { 
+                    None => plain_text("this function"),
+                    Some(symbol) => ReportText::Value(symbol),
+                };
+
+                report_mismatch(
+                    filename,
+                    &category,
+                    found,
+                    expected_type,
+                    region,
+                    Some(expr_region),
+                    Concat(vec![ plain_text(&format!("The {} argument to ", ith))
+                        , this_function.clone(), plain_text(" is not what I expect:" )]),
+                    plain_text("This argument is"),
+                    Concat(vec![ plain_text("But "), this_function, plain_text(&format!(" needs the {} argument to be:", ith))]),
+                    plain_text(""),
+                )
+                
+            }
             other => {
-                //    AnonymousFnArg { arg_index: u8 },
                 //    NamedFnArg(String /* function name */, u8 /* arg index */),
                 //    AnonymousFnCall { arity: u8 },
                 //    NamedFnCall(String /* function name */, u8 /* arity */),

compiler/reporting/tests/test_reporting.rs

@@ -1161,4 +1161,37 @@ mod test_reporting {
             ),
         )
     }
+
+    #[test]
+    fn record_field_mismatch() {
+        report_problem_as(
+            indoc!(
+                r#"
+                bar = { bar : 0x3 }
+
+                f : { foo : Int } -> Bool
+                f = \_ -> True
+
+                f bar
+                "#
+            ),
+            indoc!(
+                r#"
+                The 1st argument to `f` is not what I expect:
+
+                6 ┆  f bar
+                  ┆    ^^^
+
+                This `bar` value is a:
+
+                    { bar : Int }
+
+                But `f` needs the 1st argument to be:
+
+                    { foo : Int }
+
+                "#
+            ),
+        )
+    }
 }

compiler/types/src/types.rs

@@ -614,10 +614,8 @@ pub enum AnnotationSource {
 
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub enum Reason {
-    AnonymousFnArg { arg_index: u8 },
-    NamedFnArg(String /* function name */, u8 /* arg index */),
-    AnonymousFnCall { arity: u8 },
-    NamedFnCall(String /* function name */, u8 /* arity */),
+    FnArg { name: Option<Symbol>, arg_index: u8 },
+    FnCall { name: Option<Symbol>, arity: u8 },
     BinOpArg(BinOp, ArgSide),
     BinOpRet(BinOp),
     FloatLiteral,