Point arg num mismatch errors back to their definition

Author: Jonathan Turner

src/librustc_typeck/check/callee.rs

@@ -193,9 +193,11 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                             -> Ty<'tcx> {
         let error_fn_sig;
 
-        let fn_sig = match callee_ty.sty {
-            ty::TyFnDef(.., &ty::BareFnTy {ref sig, ..}) |
-            ty::TyFnPtr(&ty::BareFnTy {ref sig, ..}) => sig,
+        let (fn_sig, def_span) = match callee_ty.sty {
+            ty::TyFnDef(def_id, .., &ty::BareFnTy {ref sig, ..}) => {
+                (sig, self.tcx.map.span_if_local(def_id))
+            }
+            ty::TyFnPtr(&ty::BareFnTy {ref sig, ..}) => (sig, None),
             ref t => {
                 let mut unit_variant = None;
                 if let &ty::TyAdt(adt_def, ..) = t {
@@ -241,7 +243,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                     variadic: false,
                 });
 
-                &error_fn_sig
+                (&error_fn_sig, None)
             }
         };
 
@@ -266,7 +268,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                                   &expected_arg_tys[..],
                                   arg_exprs,
                                   fn_sig.variadic,
-                                  TupleArgumentsFlag::DontTupleArguments);
+                                  TupleArgumentsFlag::DontTupleArguments,
+                                  def_span);
 
         fn_sig.output
     }
@@ -292,7 +295,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                                   &expected_arg_tys,
                                   arg_exprs,
                                   fn_sig.variadic,
-                                  TupleArgumentsFlag::TupleArguments);
+                                  TupleArgumentsFlag::TupleArguments,
+                                  None);
 
         fn_sig.output
     }

src/librustc_typeck/check/mod.rs

@@ -2465,17 +2465,19 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
             };
 
             self.check_argument_types(sp, &err_inputs[..], &[], args_no_rcvr,
-                                      false, tuple_arguments);
+                                      false, tuple_arguments, None);
             self.tcx.types.err
         } else {
             match method_fn_ty.sty {
-                ty::TyFnDef(.., ref fty) => {
+                ty::TyFnDef(def_id, .., ref fty) => {
                     // HACK(eddyb) ignore self in the definition (see above).
                     let expected_arg_tys = self.expected_types_for_fn_args(sp, expected,
                                                                            fty.sig.0.output,
                                                                            &fty.sig.0.inputs[1..]);
+
                     self.check_argument_types(sp, &fty.sig.0.inputs[1..], &expected_arg_tys[..],
-                                              args_no_rcvr, fty.sig.0.variadic, tuple_arguments);
+                                              args_no_rcvr, fty.sig.0.variadic, tuple_arguments,
+                                              self.tcx.map.span_if_local(def_id));
                     fty.sig.0.output
                 }
                 _ => {
@@ -2493,7 +2495,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                             expected_arg_tys: &[Ty<'tcx>],
                             args: &'gcx [hir::Expr],
                             variadic: bool,
-                            tuple_arguments: TupleArgumentsFlag) {
+                            tuple_arguments: TupleArgumentsFlag,
+                            def_span: Option<Span>) {
         let tcx = self.tcx;
 
         // Grab the argument types, supplying fresh type variables
@@ -2528,9 +2531,9 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
             sp
         };
 
-        fn parameter_count_error<'tcx>(sess: &Session, sp: Span, fn_inputs: &[Ty<'tcx>],
-                                       expected_count: usize, arg_count: usize, error_code: &str,
-                                       variadic: bool) {
+        fn parameter_count_error<'tcx>(sess: &Session, sp: Span, expected_count: usize,
+                                       arg_count: usize, error_code: &str, variadic: bool,
+                                       def_span: Option<Span>) {
             let mut err = sess.struct_span_err_with_code(sp,
                 &format!("this function takes {}{} parameter{} but {} parameter{} supplied",
                     if variadic {"at least "} else {""},
@@ -2540,18 +2543,12 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                     if arg_count == 1 {" was"} else {"s were"}),
                 error_code);
 
-            let input_types = fn_inputs.iter().map(|i| format!("{:?}", i)).collect::<Vec<String>>();
-            if input_types.len() > 1 {
-                err.note("the following parameter types were expected:");
-                err.note(&input_types.join(", "));
-            } else if input_types.len() > 0 {
-                err.note(&format!("the following parameter type was expected: {}",
-                                  input_types[0]));
-            } else {
-                err.span_label(sp, &format!("expected {}{} parameter{}",
-                                            if variadic {"at least "} else {""},
-                                            expected_count,
-                                            if expected_count == 1 {""} else {"s"}));
+            err.span_label(sp, &format!("expected {}{} parameter{}",
+                                        if variadic {"at least "} else {""},
+                                        expected_count,
+                                        if expected_count == 1 {""} else {"s"}));
+            if let Some(def_s) = def_span {
+                err.span_label(def_s, &format!("defined here"));
             }
             err.emit();
         }
@@ -2560,8 +2557,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
             let tuple_type = self.structurally_resolved_type(sp, fn_inputs[0]);
             match tuple_type.sty {
                 ty::TyTuple(arg_types) if arg_types.len() != args.len() => {
-                    parameter_count_error(tcx.sess, sp_args, fn_inputs, arg_types.len(), args.len(),
-                                          "E0057", false);
+                    parameter_count_error(tcx.sess, sp_args, arg_types.len(), args.len(),
+                                          "E0057", false, def_span);
                     expected_arg_tys = &[];
                     self.err_args(args.len())
                 }
@@ -2589,14 +2586,14 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
             if supplied_arg_count >= expected_arg_count {
                 fn_inputs.to_vec()
             } else {
-                parameter_count_error(tcx.sess, sp_args, fn_inputs, expected_arg_count,
-                                      supplied_arg_count, "E0060", true);
+                parameter_count_error(tcx.sess, sp_args, expected_arg_count,
+                                      supplied_arg_count, "E0060", true, def_span);
                 expected_arg_tys = &[];
                 self.err_args(supplied_arg_count)
             }
         } else {
-            parameter_count_error(tcx.sess, sp_args, fn_inputs, expected_arg_count,
-                                  supplied_arg_count, "E0061", false);
+            parameter_count_error(tcx.sess, sp_args, expected_arg_count,
+                                  supplied_arg_count, "E0061", false, def_span);
             expected_arg_tys = &[];
             self.err_args(supplied_arg_count)
         };

src/test/compile-fail/E0060.rs

@@ -10,10 +10,11 @@
 
 extern "C" {
     fn printf(_: *const u8, ...) -> u32;
+    //~^ NOTE defined here
 }
 
 fn main() {
     unsafe { printf(); }
     //~^ ERROR E0060
-    //~| NOTE the following parameter type was expected: *const u8
+    //~| expected at least 1 parameter
 }

src/test/compile-fail/E0061.rs

@@ -9,16 +9,17 @@
 // except according to those terms.
 
 fn f(a: u16, b: &str) {}
+//~^ NOTE defined here
 
 fn f2(a: u16) {}
+//~^ NOTE defined here
 
 fn main() {
     f(0);
     //~^ ERROR E0061
-    //~| NOTE the following parameter types were expected:
-    //~| NOTE u16, &str
+    //~| expected 2 parameters
 
     f2();
     //~^ ERROR E0061
-    //~| NOTE the following parameter type was expected: u16
+    //~| expected 1 parameter
 }

src/test/compile-fail/issue-18819.rs

@@ -19,12 +19,12 @@ impl Foo for X {
 }
 
 fn print_x(_: &Foo<Item=bool>, extra: &str) {
+    //~^ NOTE defined here
     println!("{}", extra);
 }
 
 fn main() {
     print_x(X);
-    //~^ ERROR this function takes 2 parameters but 1 parameter was supplied
-    //~| NOTE the following parameter types were expected:
-    //~| NOTE &Foo<Item=bool>, &str
+    //~^ ERROR E0061
+    //~| NOTE expected 2 parameters
 }

src/test/compile-fail/issue-3044.rs

@@ -14,7 +14,5 @@ fn main() {
     needlesArr.iter().fold(|x, y| {
     });
     //~^^ ERROR this function takes 2 parameters but 1 parameter was supplied
-    //~| NOTE the following parameter types were expected
-    //~| NOTE _, _
-    // the first error is, um, non-ideal.
+    //~| NOTE expected 2 parameters
 }

src/test/compile-fail/issue-4935.rs

@@ -11,6 +11,7 @@
 // Regression test for issue #4935
 
 fn foo(a: usize) {}
+//~^ defined here
 fn main() { foo(5, 6) }
 //~^ ERROR this function takes 1 parameter but 2 parameters were supplied
-//~| NOTE the following parameter type was expected
+//~| NOTE expected 1 parameter

src/test/compile-fail/method-call-err-msg.rs

@@ -13,19 +13,21 @@
 pub struct Foo;
 impl Foo {
     fn zero(self) -> Foo { self }
+    //~^ NOTE defined here
     fn one(self, _: isize) -> Foo { self }
+    //~^ NOTE defined here
     fn two(self, _: isize, _: isize) -> Foo { self }
+    //~^ NOTE defined here
 }
 
 fn main() {
     let x = Foo;
     x.zero(0)   //~ ERROR this function takes 0 parameters but 1 parameter was supplied
      //~^ NOTE expected 0 parameters
      .one()     //~ ERROR this function takes 1 parameter but 0 parameters were supplied
-     //~^ NOTE the following parameter type was expected
+     //~^ NOTE expected 1 parameter
      .two(0);   //~ ERROR this function takes 2 parameters but 1 parameter was supplied
-     //~^ NOTE the following parameter types were expected
-     //~| NOTE isize, isize
+     //~^ NOTE expected 2 parameters
 
     let y = Foo;
     y.zero()

src/test/compile-fail/not-enough-arguments.rs

@@ -13,12 +13,12 @@
 // unrelated errors.
 
 fn foo(a: isize, b: isize, c: isize, d:isize) {
+  //~^ NOTE defined here
   panic!();
 }
 
 fn main() {
   foo(1, 2, 3);
   //~^ ERROR this function takes 4 parameters but 3
-  //~| NOTE the following parameter types were expected:
-  //~| NOTE isize, isize, isize, isize
+  //~| NOTE expected 4 parameters
 }

src/test/compile-fail/overloaded-calls-bad.rs

@@ -41,8 +41,8 @@ fn main() {
     //~| NOTE found type
     let ans = s();
     //~^ ERROR this function takes 1 parameter but 0 parameters were supplied
-    //~| NOTE the following parameter type was expected
+    //~| NOTE expected 1 parameter
     let ans = s("burma", "shave");
     //~^ ERROR this function takes 1 parameter but 2 parameters were supplied
-    //~| NOTE the following parameter type was expected
+    //~| NOTE expected 1 parameter
 }