Auto merge of #45123 - goffrie:fix-method-unit-call, r=oli-obk

Provide the full span of method calls to `check_argument_types`

... so that it includes the span of the passed arguments, not just the name of the called method.

Fixes #44760.

Author: bors

src/librustc_typeck/check/callee.rs

@@ -271,6 +271,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                                             fn_sig.output(),
                                             fn_sig.inputs());
         self.check_argument_types(call_expr.span,
+                                  call_expr.span,
                                   fn_sig.inputs(),
                                   &expected_arg_tys[..],
                                   arg_exprs,
@@ -298,6 +299,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                                                                fn_sig.inputs());
 
         self.check_argument_types(call_expr.span,
+                                  call_expr.span,
                                   fn_sig.inputs(),
                                   &expected_arg_tys,
                                   arg_exprs,
@@ -315,6 +317,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                                method_callee: MethodCallee<'tcx>)
                                -> Ty<'tcx> {
         let output_type = self.check_method_argument_types(call_expr.span,
+                                                           call_expr.span,
                                                            Ok(method_callee),
                                                            arg_exprs,
                                                            TupleArgumentsFlag::TupleArguments,

src/librustc_typeck/check/mod.rs

@@ -2352,6 +2352,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
 
     fn check_method_argument_types(&self,
                                    sp: Span,
+                                   expr_sp: Span,
                                    method: Result<MethodCallee<'tcx>, ()>,
                                    args_no_rcvr: &'gcx [hir::Expr],
                                    tuple_arguments: TupleArgumentsFlag,
@@ -2371,7 +2372,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                 TupleArguments => vec![self.tcx.intern_tup(&err_inputs[..], false)],
             };
 
-            self.check_argument_types(sp, &err_inputs[..], &[], args_no_rcvr,
+            self.check_argument_types(sp, expr_sp, &err_inputs[..], &[], args_no_rcvr,
                                       false, tuple_arguments, None);
             return self.tcx.types.err;
         }
@@ -2384,7 +2385,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
             method.sig.output(),
             &method.sig.inputs()[1..]
         );
-        self.check_argument_types(sp, &method.sig.inputs()[1..], &expected_arg_tys[..],
+        self.check_argument_types(sp, expr_sp, &method.sig.inputs()[1..], &expected_arg_tys[..],
                                   args_no_rcvr, method.sig.variadic, tuple_arguments,
                                   self.tcx.hir.span_if_local(method.def_id));
         method.sig.output()
@@ -2394,6 +2395,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
     /// method calls and overloaded operators.
     fn check_argument_types(&self,
                             sp: Span,
+                            expr_sp: Span,
                             fn_inputs: &[Ty<'tcx>],
                             expected_arg_tys: &[Ty<'tcx>],
                             args: &'gcx [hir::Expr],
@@ -2434,9 +2436,15 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
             sp
         };
 
-        fn parameter_count_error<'tcx>(sess: &Session, sp: Span, expected_count: usize,
-                                       arg_count: usize, error_code: &str, variadic: bool,
-                                       def_span: Option<Span>, sugg_unit: bool) {
+        fn parameter_count_error<'tcx>(sess: &Session,
+                                       sp: Span,
+                                       expr_sp: Span,
+                                       expected_count: usize,
+                                       arg_count: usize,
+                                       error_code: &str,
+                                       variadic: bool,
+                                       def_span: Option<Span>,
+                                       sugg_unit: bool) {
             let mut err = sess.struct_span_err_with_code(sp,
                 &format!("this function takes {}{} parameter{} but {} parameter{} supplied",
                     if variadic {"at least "} else {""},
@@ -2450,12 +2458,12 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                 err.span_label(def_s, "defined here");
             }
             if sugg_unit {
-                let sugg_span = sp.end_point();
+                let sugg_span = expr_sp.end_point();
                 // remove closing `)` from the span
                 let sugg_span = sugg_span.with_hi(sugg_span.lo());
                 err.span_suggestion(
                     sugg_span,
-                    "expected the unit value `()`. You can create one with a pair of parenthesis",
+                    "expected the unit value `()`; create it with empty parentheses",
                     String::from("()"));
             } else {
                 err.span_label(sp, format!("expected {}{} parameter{}",
@@ -2470,7 +2478,7 @@ 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, arg_types.len(), args.len(),
+                    parameter_count_error(tcx.sess, sp_args, expr_sp, arg_types.len(), args.len(),
                                           "E0057", false, def_span, false);
                     expected_arg_tys = &[];
                     self.err_args(args.len())
@@ -2499,7 +2507,7 @@ 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, expected_arg_count,
+                parameter_count_error(tcx.sess, sp_args, expr_sp, expected_arg_count,
                                       supplied_arg_count, "E0060", true, def_span, false);
                 expected_arg_tys = &[];
                 self.err_args(supplied_arg_count)
@@ -2513,7 +2521,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
             } else {
                 false
             };
-            parameter_count_error(tcx.sess, sp_args, expected_arg_count,
+            parameter_count_error(tcx.sess, sp_args, expr_sp, expected_arg_count,
                                   supplied_arg_count, "E0061", false, def_span, sugg_unit);
             expected_arg_tys = &[];
             self.err_args(supplied_arg_count)
@@ -2866,7 +2874,9 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
         };
 
         // Call the generic checker.
-        self.check_method_argument_types(span, method,
+        self.check_method_argument_types(span,
+                                         expr.span,
+                                         method,
                                          &args[1..],
                                          DontTupleArguments,
                                          expected)

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

@@ -0,0 +1,44 @@
+error[E0061]: this function takes 0 parameters but 1 parameter was supplied
+  --> $DIR/method-call-err-msg.rs:25:12
+   |
+15 |     fn zero(self) -> Foo { self }
+   |     ----------------------------- defined here
+...
+25 |     x.zero(0)   //~ ERROR this function takes 0 parameters but 1 parameter was supplied
+   |            ^ expected 0 parameters
+
+error[E0061]: this function takes 1 parameter but 0 parameters were supplied
+  --> $DIR/method-call-err-msg.rs:27:7
+   |
+17 |     fn one(self, _: isize) -> Foo { self }
+   |     -------------------------------------- defined here
+...
+27 |      .one()     //~ ERROR this function takes 1 parameter but 0 parameters were supplied
+   |       ^^^ expected 1 parameter
+
+error[E0061]: this function takes 2 parameters but 1 parameter was supplied
+  --> $DIR/method-call-err-msg.rs:29:11
+   |
+19 |     fn two(self, _: isize, _: isize) -> Foo { self }
+   |     ------------------------------------------------ defined here
+...
+29 |      .two(0);   //~ ERROR this function takes 2 parameters but 1 parameter was supplied
+   |           ^ expected 2 parameters
+
+error[E0599]: no method named `take` found for type `Foo` in the current scope
+  --> $DIR/method-call-err-msg.rs:34:7
+   |
+34 |      .take()    //~ ERROR no method named `take` found for type `Foo` in the current scope
+   |       ^^^^
+   |
+   = note: the method `take` exists but the following trait bounds were not satisfied:
+           `&mut Foo : std::iter::Iterator`
+   = help: items from traits can only be used if the trait is implemented and in scope
+   = note: the following traits define an item `take`, perhaps you need to implement one of them:
+           candidate #1: `std::collections::hash::Recover`
+           candidate #2: `std::io::Read`
+           candidate #3: `std::iter::Iterator`
+           candidate #4: `alloc::btree::Recover`
+
+error: aborting due to 4 previous errors
+

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

@@ -11,9 +11,17 @@
 fn foo(():(), ():()) {}
 fn bar(():()) {}
 
+struct S;
+impl S {
+    fn baz(self, (): ()) { }
+    fn generic<T>(self, _: T) { }
+}
+
 fn main() {
     let _: Result<(), String> = Ok();
     foo();
     foo(());
     bar();
+    S.baz();
+    S.generic::<()>();
 }

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

@@ -1,45 +1,73 @@
 error[E0061]: this function takes 1 parameter but 0 parameters were supplied
-  --> $DIR/missing-unit-argument.rs:15:33
+  --> $DIR/missing-unit-argument.rs:21:33
    |
-15 |     let _: Result<(), String> = Ok();
+21 |     let _: Result<(), String> = Ok();
    |                                 ^^^^
    |
-help: expected the unit value `()`. You can create one with a pair of parenthesis
+help: expected the unit value `()`; create it with empty parentheses
    |
-15 |     let _: Result<(), String> = Ok(());
+21 |     let _: Result<(), String> = Ok(());
    |                                    ^^
 
 error[E0061]: this function takes 2 parameters but 0 parameters were supplied
-  --> $DIR/missing-unit-argument.rs:16:5
+  --> $DIR/missing-unit-argument.rs:22:5
    |
 11 | fn foo(():(), ():()) {}
    | ----------------------- defined here
 ...
-16 |     foo();
+22 |     foo();
    |     ^^^^^ expected 2 parameters
 
 error[E0061]: this function takes 2 parameters but 1 parameter was supplied
-  --> $DIR/missing-unit-argument.rs:17:9
+  --> $DIR/missing-unit-argument.rs:23:9
    |
 11 | fn foo(():(), ():()) {}
    | ----------------------- defined here
 ...
-17 |     foo(());
+23 |     foo(());
    |         ^^ expected 2 parameters
 
 error[E0061]: this function takes 1 parameter but 0 parameters were supplied
-  --> $DIR/missing-unit-argument.rs:18:5
+  --> $DIR/missing-unit-argument.rs:24:5
    |
 12 | fn bar(():()) {}
    | ---------------- defined here
 ...
-18 |     bar();
+24 |     bar();
    |     ^^^^^
    |
-help: expected the unit value `()`. You can create one with a pair of parenthesis
+help: expected the unit value `()`; create it with empty parentheses
    |
-18 |     bar(());
+24 |     bar(());
    |         ^^
 
-error: aborting due to 4 previous errors
+error[E0061]: this function takes 1 parameter but 0 parameters were supplied
+  --> $DIR/missing-unit-argument.rs:25:7
+   |
+16 |     fn baz(self, (): ()) { }
+   |     ------------------------ defined here
+...
+25 |     S.baz();
+   |       ^^^
+   |
+help: expected the unit value `()`; create it with empty parentheses
+   |
+25 |     S.baz(());
+   |           ^^
+
+error[E0061]: this function takes 1 parameter but 0 parameters were supplied
+  --> $DIR/missing-unit-argument.rs:26:7
+   |
+17 |     fn generic<T>(self, _: T) { }
+   |     ----------------------------- defined here
+...
+26 |     S.generic::<()>();
+   |       ^^^^^^^
+   |
+help: expected the unit value `()`; create it with empty parentheses
+   |
+26 |     S.generic::<()>(());
+   |                     ^^
+
+error: aborting due to 6 previous errors