Rollup merge of #99646 - compiler-errors:arg-mismatch-single-arg-label, r=estebank

Only point out a single function parameter if we have a single arg incompatibility

Fixes #99635

compiler/rustc_parse/src/parser/expr.rs

@@ -2268,7 +2268,7 @@ impl<'a> Parser<'a> {
                     attrs: attrs.into(),
                     ty,
                     pat,
-                    span: lo.to(this.token.span),
+                    span: lo.to(this.prev_token.span),
                     id: DUMMY_NODE_ID,
                     is_placeholder: false,
                 },

compiler/rustc_typeck/src/check/fn_ctxt/checks.rs

@@ -440,7 +440,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         call_expr: &hir::Expr<'tcx>,
     ) {
         // Next, let's construct the error
-        let (error_span, full_call_span, ctor_of) = match &call_expr.kind {
+        let (error_span, full_call_span, ctor_of, is_method) = match &call_expr.kind {
             hir::ExprKind::Call(
                 hir::Expr { hir_id, span, kind: hir::ExprKind::Path(qpath), .. },
                 _,
@@ -448,12 +448,12 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 if let Res::Def(DefKind::Ctor(of, _), _) =
                     self.typeck_results.borrow().qpath_res(qpath, *hir_id)
                 {
-                    (call_span, *span, Some(of))
+                    (call_span, *span, Some(of), false)
                 } else {
-                    (call_span, *span, None)
+                    (call_span, *span, None, false)
                 }
             }
-            hir::ExprKind::Call(hir::Expr { span, .. }, _) => (call_span, *span, None),
+            hir::ExprKind::Call(hir::Expr { span, .. }, _) => (call_span, *span, None, false),
             hir::ExprKind::MethodCall(path_segment, _, span) => {
                 let ident_span = path_segment.ident.span;
                 let ident_span = if let Some(args) = path_segment.args {
@@ -461,9 +461,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 } else {
                     ident_span
                 };
-                (
+                // methods are never ctors
-                    *span, ident_span, None, // methods are never ctors
+                (*span, ident_span, None, true)
-                )
             }
             k => span_bug!(call_span, "checking argument types on a non-call: `{:?}`", k),
         };
@@ -659,7 +658,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                             Applicability::MachineApplicable,
                         );
                     };
-                    self.label_fn_like(&mut err, fn_def_id, callee_ty);
+                    self.label_fn_like(&mut err, fn_def_id, callee_ty, Some(mismatch_idx), is_method);
                     err.emit();
                     return;
                 }
@@ -701,16 +700,14 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
 
         errors.drain_filter(|error| {
-                let Error::Invalid(provided_idx, expected_idx, Compatibility::Incompatible(error)) = error else { return false };
+                let Error::Invalid(provided_idx, expected_idx, Compatibility::Incompatible(Some(e))) = error else { return false };
                 let (provided_ty, provided_span) = provided_arg_tys[*provided_idx];
                 let (expected_ty, _) = formal_and_expected_inputs[*expected_idx];
                 let cause = &self.misc(provided_span);
                 let trace = TypeTrace::types(cause, true, expected_ty, provided_ty);
-                if let Some(e) = error {
+                if !matches!(trace.cause.as_failure_code(e), FailureCode::Error0308(_)) {
-                    if !matches!(trace.cause.as_failure_code(e), FailureCode::Error0308(_)) {
+                    self.report_and_explain_type_error(trace, e).emit();
-                        self.report_and_explain_type_error(trace, e).emit();
+                    return true;
-                        return true;
-                    }
                 }
                 false
             });
@@ -749,7 +746,13 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 format!("arguments to this {} are incorrect", call_name),
             );
             // Call out where the function is defined
-            self.label_fn_like(&mut err, fn_def_id, callee_ty);
+            self.label_fn_like(
+                &mut err,
+                fn_def_id,
+                callee_ty,
+                Some(expected_idx.as_usize()),
+                is_method,
+            );
             err.emit();
             return;
         }
@@ -1031,7 +1034,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
 
         // Call out where the function is defined
-        self.label_fn_like(&mut err, fn_def_id, callee_ty);
+        self.label_fn_like(&mut err, fn_def_id, callee_ty, None, is_method);
 
         // And add a suggestion block for all of the parameters
         let suggestion_text = match suggestion_text {
@@ -1781,6 +1784,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         err: &mut Diagnostic,
         callable_def_id: Option<DefId>,
         callee_ty: Option<Ty<'tcx>>,
+        // A specific argument should be labeled, instead of all of them
+        expected_idx: Option<usize>,
+        is_method: bool,
     ) {
         let Some(mut def_id) = callable_def_id else {
             return;
@@ -1881,14 +1887,30 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 .get_if_local(def_id)
                 .and_then(|node| node.body_id())
                 .into_iter()
-                .flat_map(|id| self.tcx.hir().body(id).params);
+                .flat_map(|id| self.tcx.hir().body(id).params)
+                .skip(if is_method { 1 } else { 0 });
 
-            for param in params {
+            for (_, param) in params
+                .into_iter()
+                .enumerate()
+                .filter(|(idx, _)| expected_idx.map_or(true, |expected_idx| expected_idx == *idx))
+            {
                 spans.push_span_label(param.span, "");
             }
 
             let def_kind = self.tcx.def_kind(def_id);
             err.span_note(spans, &format!("{} defined here", def_kind.descr(def_id)));
+        } else if let Some(hir::Node::Expr(e)) = self.tcx.hir().get_if_local(def_id)
+            && let hir::ExprKind::Closure(hir::Closure { body, .. }) = &e.kind
+        {
+            let param = expected_idx
+                .and_then(|expected_idx| self.tcx.hir().body(*body).params.get(expected_idx));
+            let (kind, span) = if let Some(param) = param {
+                ("closure parameter", param.span)
+            } else {
+                ("closure", self.tcx.def_span(def_id))
+            };
+            err.span_note(span, &format!("{} defined here", kind));
         } else {
             let def_kind = self.tcx.def_kind(def_id);
             err.span_note(

src/test/ui/argument-suggestions/invalid_arguments.stderr

@@ -24,7 +24,7 @@ note: function defined here
   --> $DIR/invalid_arguments.rs:6:4
    |
 LL | fn two_arg_same(_a: i32, _b: i32) {}
-   |    ^^^^^^^^^^^^ -------  -------
+   |    ^^^^^^^^^^^^          -------
 
 error[E0308]: mismatched types
   --> $DIR/invalid_arguments.rs:17:16
@@ -38,7 +38,7 @@ note: function defined here
   --> $DIR/invalid_arguments.rs:6:4
    |
 LL | fn two_arg_same(_a: i32, _b: i32) {}
-   |    ^^^^^^^^^^^^ -------  -------
+   |    ^^^^^^^^^^^^ -------
 
 error[E0308]: arguments to this function are incorrect
   --> $DIR/invalid_arguments.rs:18:3
@@ -66,7 +66,7 @@ note: function defined here
   --> $DIR/invalid_arguments.rs:7:4
    |
 LL | fn two_arg_diff(_a: i32, _b: f32) {}
-   |    ^^^^^^^^^^^^ -------  -------
+   |    ^^^^^^^^^^^^          -------
 
 error[E0308]: mismatched types
   --> $DIR/invalid_arguments.rs:20:16
@@ -80,7 +80,7 @@ note: function defined here
   --> $DIR/invalid_arguments.rs:7:4
    |
 LL | fn two_arg_diff(_a: i32, _b: f32) {}
-   |    ^^^^^^^^^^^^ -------  -------
+   |    ^^^^^^^^^^^^ -------
 
 error[E0308]: arguments to this function are incorrect
   --> $DIR/invalid_arguments.rs:21:3
@@ -108,7 +108,7 @@ note: function defined here
   --> $DIR/invalid_arguments.rs:8:4
    |
 LL | fn three_arg_diff(_a: i32, _b: f32, _c: &str) {}
-   |    ^^^^^^^^^^^^^^ -------  -------  --------
+   |    ^^^^^^^^^^^^^^ -------
 
 error[E0308]: mismatched types
   --> $DIR/invalid_arguments.rs:25:21
@@ -122,7 +122,7 @@ note: function defined here
   --> $DIR/invalid_arguments.rs:8:4
    |
 LL | fn three_arg_diff(_a: i32, _b: f32, _c: &str) {}
-   |    ^^^^^^^^^^^^^^ -------  -------  --------
+   |    ^^^^^^^^^^^^^^          -------
 
 error[E0308]: mismatched types
   --> $DIR/invalid_arguments.rs:26:26
@@ -136,7 +136,7 @@ note: function defined here
   --> $DIR/invalid_arguments.rs:8:4
    |
 LL | fn three_arg_diff(_a: i32, _b: f32, _c: &str) {}
-   |    ^^^^^^^^^^^^^^ -------  -------  --------
+   |    ^^^^^^^^^^^^^^                   --------
 
 error[E0308]: arguments to this function are incorrect
   --> $DIR/invalid_arguments.rs:28:3
@@ -207,7 +207,7 @@ note: function defined here
   --> $DIR/invalid_arguments.rs:9:4
    |
 LL | fn three_arg_repeat(_a: i32, _b: i32, _c: &str) {}
-   |    ^^^^^^^^^^^^^^^^ -------  -------  --------
+   |    ^^^^^^^^^^^^^^^^ -------
 
 error[E0308]: mismatched types
   --> $DIR/invalid_arguments.rs:35:23
@@ -221,7 +221,7 @@ note: function defined here
   --> $DIR/invalid_arguments.rs:9:4
    |
 LL | fn three_arg_repeat(_a: i32, _b: i32, _c: &str) {}
-   |    ^^^^^^^^^^^^^^^^ -------  -------  --------
+   |    ^^^^^^^^^^^^^^^^          -------
 
 error[E0308]: mismatched types
   --> $DIR/invalid_arguments.rs:36:26
@@ -235,7 +235,7 @@ note: function defined here
   --> $DIR/invalid_arguments.rs:9:4
    |
 LL | fn three_arg_repeat(_a: i32, _b: i32, _c: &str) {}
-   |    ^^^^^^^^^^^^^^^^ -------  -------  --------
+   |    ^^^^^^^^^^^^^^^^                   --------
 
 error[E0308]: arguments to this function are incorrect
   --> $DIR/invalid_arguments.rs:38:3

src/test/ui/argument-suggestions/too-long.rs

@@ -0,0 +1,41 @@
+struct Qux;
+
+impl Qux {
+    fn foo(
+        &self,
+        a: i32,
+        b: i32,
+        c: i32,
+        d: i32,
+        e: i32,
+        f: i32,
+        g: i32,
+        h: i32,
+        i: i32,
+        j: i32,
+        k: i32,
+        l: i32,
+    ) {
+    }
+}
+
+fn what(
+    qux: &Qux,
+    a: i32,
+    b: i32,
+    c: i32,
+    d: i32,
+    e: i32,
+    f: &i32,
+    g: i32,
+    h: i32,
+    i: i32,
+    j: i32,
+    k: i32,
+    l: i32,
+) {
+    qux.foo(a, b, c, d, e, f, g, h, i, j, k, l);
+    //~^ ERROR mismatched types
+}
+
+fn main() {}

src/test/ui/argument-suggestions/too-long.stderr

@@ -0,0 +1,24 @@
+error[E0308]: mismatched types
+  --> $DIR/too-long.rs:37:28
+   |
+LL |     qux.foo(a, b, c, d, e, f, g, h, i, j, k, l);
+   |         ---                ^ expected `i32`, found `&i32`
+   |         |
+   |         arguments to this function are incorrect
+   |
+note: associated function defined here
+  --> $DIR/too-long.rs:4:8
+   |
+LL |     fn foo(
+   |        ^^^
+...
+LL |         f: i32,
+   |         ------
+help: consider dereferencing the borrow
+   |
+LL |     qux.foo(a, b, c, d, e, *f, g, h, i, j, k, l);
+   |                            +
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0308`.

src/test/ui/associated-types/associated-type-projection-from-supertrait.stderr

@@ -10,7 +10,7 @@ note: function defined here
   --> $DIR/associated-type-projection-from-supertrait.rs:25:4
    |
 LL | fn dent<C:Car>(c: C, color: C::Color) { c.chip_paint(color) }
-   |    ^^^^        ----  ---------------
+   |    ^^^^              ---------------
 
 error[E0308]: mismatched types
   --> $DIR/associated-type-projection-from-supertrait.rs:28:23
@@ -24,7 +24,7 @@ note: function defined here
   --> $DIR/associated-type-projection-from-supertrait.rs:25:4
    |
 LL | fn dent<C:Car>(c: C, color: C::Color) { c.chip_paint(color) }
-   |    ^^^^        ----  ---------------
+   |    ^^^^              ---------------
 
 error[E0308]: mismatched types
   --> $DIR/associated-type-projection-from-supertrait.rs:32:28
@@ -38,7 +38,7 @@ note: associated function defined here
   --> $DIR/associated-type-projection-from-supertrait.rs:12:8
    |
 LL |     fn chip_paint(&self, c: Self::Color) { }
-   |        ^^^^^^^^^^ -----  --------------
+   |        ^^^^^^^^^^        --------------
 
 error[E0308]: mismatched types
   --> $DIR/associated-type-projection-from-supertrait.rs:33:28
@@ -52,7 +52,7 @@ note: associated function defined here
   --> $DIR/associated-type-projection-from-supertrait.rs:12:8
    |
 LL |     fn chip_paint(&self, c: Self::Color) { }
-   |        ^^^^^^^^^^ -----  --------------
+   |        ^^^^^^^^^^        --------------
 
 error: aborting due to 4 previous errors
 

src/test/ui/associated-types/associated-types-path-2.stderr

@@ -10,7 +10,7 @@ note: function defined here
   --> $DIR/associated-types-path-2.rs:13:8
    |
 LL | pub fn f1<T: Foo>(a: T, x: T::A) {}
-   |        ^^         ----  -------
+   |        ^^               -------
 help: change the type of the numeric literal from `i32` to `u32`
    |
 LL |     f1(2i32, 4u32);

src/test/ui/async-await/generator-desc.stderr

@@ -42,7 +42,7 @@ note: function defined here
   --> $DIR/generator-desc.rs:8:4
    |
 LL | fn fun<F: Future<Output = ()>>(f1: F, f2: F) {}
-   |    ^^^                         -----  -----
+   |    ^^^                                -----
 
 error[E0308]: mismatched types
   --> $DIR/generator-desc.rs:14:26
@@ -67,7 +67,7 @@ note: function defined here
   --> $DIR/generator-desc.rs:8:4
    |
 LL | fn fun<F: Future<Output = ()>>(f1: F, f2: F) {}
-   |    ^^^                         -----  -----
+   |    ^^^                                -----
 
 error: aborting due to 3 previous errors
 

src/test/ui/coercion/coerce-reborrow-multi-arg-fail.stderr

@@ -12,7 +12,7 @@ note: function defined here
   --> $DIR/coerce-reborrow-multi-arg-fail.rs:1:4
    |
 LL | fn test<T>(_a: T, _b: T) {}
-   |    ^^^^    -----  -----
+   |    ^^^^           -----
 
 error: aborting due to previous error
 

src/test/ui/coercion/coerce-to-bang.stderr

@@ -12,7 +12,7 @@ note: function defined here
   --> $DIR/coerce-to-bang.rs:3:4
    |
 LL | fn foo(x: usize, y: !, z: usize) { }
-   |    ^^^ --------  ----  --------
+   |    ^^^           ----
 
 error[E0308]: mismatched types
   --> $DIR/coerce-to-bang.rs:18:13
@@ -28,7 +28,7 @@ note: function defined here
   --> $DIR/coerce-to-bang.rs:3:4
    |
 LL | fn foo(x: usize, y: !, z: usize) { }
-   |    ^^^ --------  ----  --------
+   |    ^^^           ----
 
 error[E0308]: mismatched types
   --> $DIR/coerce-to-bang.rs:26:12
@@ -44,7 +44,7 @@ note: function defined here
   --> $DIR/coerce-to-bang.rs:3:4
    |
 LL | fn foo(x: usize, y: !, z: usize) { }
-   |    ^^^ --------  ----  --------
+   |    ^^^           ----
 
 error[E0308]: mismatched types
   --> $DIR/coerce-to-bang.rs:36:12
@@ -60,7 +60,7 @@ note: function defined here
   --> $DIR/coerce-to-bang.rs:3:4
    |
 LL | fn foo(x: usize, y: !, z: usize) { }
-   |    ^^^ --------  ----  --------
+   |    ^^^           ----
 
 error[E0308]: mismatched types
   --> $DIR/coerce-to-bang.rs:45:12
@@ -76,7 +76,7 @@ note: function defined here
   --> $DIR/coerce-to-bang.rs:3:4
    |
 LL | fn foo(x: usize, y: !, z: usize) { }
-   |    ^^^ --------  ----  --------
+   |    ^^^           ----
 
 error[E0308]: mismatched types
   --> $DIR/coerce-to-bang.rs:50:21

src/test/ui/fn/fn-item-type.stderr

@@ -15,7 +15,7 @@ note: function defined here
   --> $DIR/fn-item-type.rs:7:4
    |
 LL | fn eq<T>(x: T, y: T) { }
-   |    ^^    ----  ----
+   |    ^^          ----
 
 error[E0308]: mismatched types
   --> $DIR/fn-item-type.rs:22:19
@@ -34,7 +34,7 @@ note: function defined here
   --> $DIR/fn-item-type.rs:7:4
    |
 LL | fn eq<T>(x: T, y: T) { }
-   |    ^^    ----  ----
+   |    ^^          ----
 
 error[E0308]: mismatched types
   --> $DIR/fn-item-type.rs:29:23
@@ -53,7 +53,7 @@ note: function defined here
   --> $DIR/fn-item-type.rs:7:4
    |
 LL | fn eq<T>(x: T, y: T) { }
-   |    ^^    ----  ----
+   |    ^^          ----
 
 error[E0308]: mismatched types
   --> $DIR/fn-item-type.rs:38:26
@@ -72,7 +72,7 @@ note: function defined here
   --> $DIR/fn-item-type.rs:7:4
    |
 LL | fn eq<T>(x: T, y: T) { }
-   |    ^^    ----  ----
+   |    ^^          ----
 
 error[E0308]: mismatched types
   --> $DIR/fn-item-type.rs:45:19
@@ -90,7 +90,7 @@ note: function defined here
   --> $DIR/fn-item-type.rs:7:4
    |
 LL | fn eq<T>(x: T, y: T) { }
-   |    ^^    ----  ----
+   |    ^^          ----
 
 error: aborting due to 5 previous errors
 

src/test/ui/issues/issue-11374.stderr

@@ -14,7 +14,7 @@ note: associated function defined here
   --> $DIR/issue-11374.rs:13:12
    |
 LL |     pub fn read_to(&mut self, vec: &mut [u8]) {
-   |            ^^^^^^^ ---------  --------------
+   |            ^^^^^^^            --------------
 
 error: aborting due to previous error
 

src/test/ui/methods/method-call-err-msg.stderr

@@ -8,7 +8,7 @@ note: associated function defined here
   --> $DIR/method-call-err-msg.rs:5:8
    |
 LL |     fn zero(self) -> Foo { self }
-   |        ^^^^ ----
+   |        ^^^^
 help: remove the extra argument
    |
 LL |     x.zero()
@@ -24,7 +24,7 @@ note: associated function defined here
   --> $DIR/method-call-err-msg.rs:6:8
    |
 LL |     fn one(self, _: isize) -> Foo { self }
-   |        ^^^ ----  --------
+   |        ^^^       --------
 help: provide the argument
    |
 LL |      .one(/* isize */)
@@ -40,7 +40,7 @@ note: associated function defined here
   --> $DIR/method-call-err-msg.rs:7:8
    |
 LL |     fn two(self, _: isize, _: isize) -> Foo { self }
-   |        ^^^ ----  --------  --------
+   |        ^^^       --------  --------
 help: provide the argument
    |
 LL |      .two(0, /* isize */);
@@ -80,7 +80,7 @@ note: associated function defined here
   --> $DIR/method-call-err-msg.rs:8:8
    |
 LL |     fn three<T>(self, _: T, _: T, _: T) -> Foo { self }
-   |        ^^^^^    ----  ----  ----  ----
+   |        ^^^^^          ----  ----  ----
 help: provide the arguments
    |
 LL |     y.three::<usize>(/* usize */, /* usize */, /* usize */);

src/test/ui/span/issue-34264.stderr

@@ -78,7 +78,7 @@ note: function defined here
   --> $DIR/issue-34264.rs:3:4
    |
 LL | fn bar(x, y: usize) {}
-   |    ^^^ -  --------
+   |    ^^^    --------
 
 error[E0061]: this function takes 2 arguments but 3 arguments were supplied
   --> $DIR/issue-34264.rs:10:5

src/test/ui/span/missing-unit-argument.stderr

@@ -72,7 +72,7 @@ note: associated function defined here
   --> $DIR/missing-unit-argument.rs:6:8
    |
 LL |     fn baz(self, (): ()) { }
-   |        ^^^ ----  ------
+   |        ^^^       ------
 help: provide the argument
    |
 LL |     S.baz(());
@@ -88,7 +88,7 @@ note: associated function defined here
   --> $DIR/missing-unit-argument.rs:7:8
    |
 LL |     fn generic<T>(self, _: T) { }
-   |        ^^^^^^^    ----  ----
+   |        ^^^^^^^          ----
 help: provide the argument
    |
 LL |     S.generic::<()>(());

src/test/ui/traits/multidispatch-bad.stderr

@@ -10,7 +10,7 @@ note: function defined here
   --> $DIR/multidispatch-bad.rs:13:4
    |
 LL | fn test<T,U>(_: T, _: U)
-   |    ^^^^      ----  ----
+   |    ^^^^            ----
 help: change the type of the numeric literal from `i32` to `u32`
    |
 LL |     test(22i32, 44u32);

src/test/ui/tuple/add-tuple-within-arguments.stderr

@@ -8,7 +8,7 @@ note: function defined here
   --> $DIR/add-tuple-within-arguments.rs:1:4
    |
 LL | fn foo(s: &str, a: (i32, i32), s2: &str) {}
-   |    ^^^ -------  -------------  --------
+   |    ^^^          -------------
 help: wrap these arguments in parentheses to construct a tuple
    |
 LL |     foo("hi", (1, 2), "hi");
@@ -28,7 +28,7 @@ note: function defined here
   --> $DIR/add-tuple-within-arguments.rs:3:4
    |
 LL | fn bar(s: &str, a: (&str,), s2: &str) {}
-   |    ^^^ -------  ----------  --------
+   |    ^^^          ----------
 help: use a trailing comma to create a tuple with one element
    |
 LL |     bar("hi", ("hi",), "hi");

src/test/ui/unboxed-closures/unboxed-closures-type-mismatch.stderr

@@ -6,11 +6,11 @@ LL |     let z = f(1_usize, 2);
    |             |
    |             arguments to this function are incorrect
    |
-note: closure defined here
+note: closure parameter defined here
-  --> $DIR/unboxed-closures-type-mismatch.rs:4:17
+  --> $DIR/unboxed-closures-type-mismatch.rs:4:18
    |
 LL |     let mut f = |x: isize, y: isize| -> isize { x + y };
-   |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |                  ^^^^^^^^
 help: change the type of the numeric literal from `usize` to `isize`
    |
 LL |     let z = f(1_isize, 2);