add error message for c# style named arguments

bless tests

compiler/rustc_parse/src/parser/expr.rs

@@ -137,6 +137,32 @@ impl<'a> Parser<'a> {
                     self.bump();
                     Ok(self.mk_expr(self.prev_token.span, ExprKind::Err))
                 }
+                None if self.may_recover()
+                    && self.prev_token.is_ident()
+                    && self.token.kind == token::Colon =>
+                {
+                    err.span_suggestion_verbose(
+                        self.prev_token.span.until(self.look_ahead(1, |t| t.span)),
+                        "if this is a parameter, remove the name for the parameter",
+                        "",
+                        Applicability::MaybeIncorrect,
+                    );
+
+                    let snapshot = self.create_snapshot_for_diagnostic();
+                    self.bump();
+                    match self.parse_expr() {
+                        Ok(expr) => {
+                            err.emit();
+                            Ok(expr)
+                        }
+
+                        Err(expr_err) => {
+                            expr_err.cancel();
+                            self.restore_snapshot(snapshot);
+                            Err(err)
+                        }
+                    }
+                }
                 _ => Err(err),
             },
         }

tests/ui/parser/issues/issue-111416.rs

@@ -1,3 +1,7 @@
 fn main() {
-    let my = monad_bind(mx, T: Try); //~ ERROR invalid `struct` delimiters or `fn` call arguments
+    let my = monad_bind(mx, T: Try);
+    //~^ ERROR expected identifier, found `:`
+    //~| ERROR cannot find value `mx`
+    //~| ERROR cannot find value `Try`
+    //~| ERROR cannot find function `monad_bind`
 }

tests/ui/parser/issues/issue-111416.stderr

@@ -1,18 +1,33 @@
-error: invalid `struct` delimiters or `fn` call arguments
-  --> $DIR/issue-111416.rs:2:14
+error: expected identifier, found `:`
+  --> $DIR/issue-111416.rs:2:30
    |
 LL |     let my = monad_bind(mx, T: Try);
-   |              ^^^^^^^^^^^^^^^^^^^^^^
-   |
-help: if `monad_bind` is a struct, use braces as delimiters
+   |                              ^ expected identifier
    |
-LL |     let my = monad_bind { mx, T: Try };
-   |                         ~            ~
-help: if `monad_bind` is a function, use the arguments directly
+help: if this is a parameter, remove the name for the parameter
    |
 LL -     let my = monad_bind(mx, T: Try);
 LL +     let my = monad_bind(mx, Try);
    |
 
-error: aborting due to 1 previous error
+error[E0425]: cannot find value `mx` in this scope
+  --> $DIR/issue-111416.rs:2:25
+   |
+LL |     let my = monad_bind(mx, T: Try);
+   |                         ^^ not found in this scope
+
+error[E0425]: cannot find value `Try` in this scope
+  --> $DIR/issue-111416.rs:2:32
+   |
+LL |     let my = monad_bind(mx, T: Try);
+   |                                ^^^ not found in this scope
+
+error[E0425]: cannot find function `monad_bind` in this scope
+  --> $DIR/issue-111416.rs:2:14
+   |
+LL |     let my = monad_bind(mx, T: Try);
+   |              ^^^^^^^^^^ not found in this scope
+
+error: aborting due to 4 previous errors
 
+For more information about this error, try `rustc --explain E0425`.

tests/ui/parser/issues/issue-34255-1.stderr

@@ -1,18 +1,37 @@
-error: invalid `struct` delimiters or `fn` call arguments
-  --> $DIR/issue-34255-1.rs:8:5
+error: expected expression, found `:`
+  --> $DIR/issue-34255-1.rs:8:22
    |
 LL |     Test::Drill(field: 42);
-   |     ^^^^^^^^^^^^^^^^^^^^^^
-   |
-help: if `Test::Drill` is a struct, use braces as delimiters
+   |                      ^ expected expression
    |
-LL |     Test::Drill { field: 42 };
-   |                 ~           ~
-help: if `Test::Drill` is a function, use the arguments directly
+help: if this is a parameter, remove the name for the parameter
    |
 LL -     Test::Drill(field: 42);
 LL +     Test::Drill(42);
    |
 
-error: aborting due to 1 previous error
+error: expected one of `!`, `)`, `,`, `.`, `::`, `?`, `{`, or an operator, found `:`
+  --> $DIR/issue-34255-1.rs:8:22
+   |
+LL |     Test::Drill(field: 42);
+   |                      ^
+   |                      |
+   |                      expected one of 8 possible tokens
+   |                      help: missing `,`
+
+error[E0425]: cannot find value `field` in this scope
+  --> $DIR/issue-34255-1.rs:8:17
+   |
+LL |     Test::Drill(field: 42);
+   |                 ^^^^^ not found in this scope
+
+error[E0533]: expected value, found struct variant `Test::Drill`
+  --> $DIR/issue-34255-1.rs:8:5
+   |
+LL |     Test::Drill(field: 42);
+   |     ^^^^^^^^^^^ not a value
+
+error: aborting due to 4 previous errors
 
+Some errors have detailed explanations: E0425, E0533.
+For more information about an error, try `rustc --explain E0425`.

tests/ui/parser/issues/issue-44406.stderr

@@ -1,22 +1,55 @@
-error: invalid `struct` delimiters or `fn` call arguments
-  --> $DIR/issue-44406.rs:3:9
+error: expected expression, found `:`
+  --> $DIR/issue-44406.rs:3:16
    |
 LL |         bar(baz: $rest)
-   |         ^^^^^^^^^^^^^^^
+   |                ^ expected expression
 ...
 LL |     foo!(true);
    |     ---------- in this macro invocation
    |
    = note: this error originates in the macro `foo` (in Nightly builds, run with -Z macro-backtrace for more info)
-help: if `bar` is a struct, use braces as delimiters
-   |
-LL |         bar { baz: $rest }
-   |             ~            ~
-help: if `bar` is a function, use the arguments directly
+help: if this is a parameter, remove the name for the parameter
    |
 LL -         bar(baz: $rest)
 LL +         bar(: $rest)
    |
 
-error: aborting due to 1 previous error
+error: expected one of `!`, `)`, `,`, `.`, `::`, `?`, `{`, or an operator, found `:`
+  --> $DIR/issue-44406.rs:3:16
+   |
+LL |         bar(baz: $rest)
+   |                ^
+   |                |
+   |                expected one of 8 possible tokens
+   |                help: missing `,`
+...
+LL |     foo!(true);
+   |     ---------- in this macro invocation
+   |
+   = note: this error originates in the macro `foo` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error[E0425]: cannot find value `baz` in this scope
+  --> $DIR/issue-44406.rs:3:13
+   |
+LL |         bar(baz: $rest)
+   |             ^^^ not found in this scope
+...
+LL |     foo!(true);
+   |     ---------- in this macro invocation
+   |
+   = note: this error originates in the macro `foo` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error[E0425]: cannot find function `bar` in this scope
+  --> $DIR/issue-44406.rs:3:9
+   |
+LL |         bar(baz: $rest)
+   |         ^^^ not found in this scope
+...
+LL |     foo!(true);
+   |     ---------- in this macro invocation
+   |
+   = note: this error originates in the macro `foo` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: aborting due to 4 previous errors
 
+For more information about this error, try `rustc --explain E0425`.

tests/ui/parser/issues/issue-91461.stderr

@@ -1,14 +1,35 @@
+error: expected expression, found `:`
+  --> $DIR/issue-91461.rs:2:8
+   |
+LL |     a(_:b:,)
+   |        ^ expected expression
+   |
+help: if this is a parameter, remove the name for the parameter
+   |
+LL -     a(_:b:,)
+LL +     a(b:,)
+   |
+
+error: expected one of `)`, `,`, `.`, `?`, or an operator, found `:`
+  --> $DIR/issue-91461.rs:2:8
+   |
+LL |     a(_:b:,)
+   |        ^
+   |        |
+   |        expected one of `)`, `,`, `.`, `?`, or an operator
+   |        help: missing `,`
+
 error: expected identifier, found reserved identifier `_`
   --> $DIR/issue-91461.rs:2:7
    |
 LL |     a(_:b:,)
    |       ^ expected identifier, found reserved identifier
 
-error: expected one of `)`, `,`, `.`, `?`, or an operator, found `:`
-  --> $DIR/issue-91461.rs:2:8
+error: expected one of `!`, `)`, `,`, `.`, `::`, `?`, `{`, or an operator, found `:`
+  --> $DIR/issue-91461.rs:2:10
    |
 LL |     a(_:b:,)
-   |        ^ expected one of `)`, `,`, `.`, `?`, or an operator
+   |          ^ expected one of 8 possible tokens
 
-error: aborting due to 2 previous errors
+error: aborting due to 4 previous errors
 

tests/ui/parser/recover/recover-from-bad-variant.stderr

@@ -1,18 +1,62 @@
-error: invalid `struct` delimiters or `fn` call arguments
-  --> $DIR/recover-from-bad-variant.rs:7:13
+error: expected expression, found `:`
+  --> $DIR/recover-from-bad-variant.rs:7:24
+   |
+LL |     let x = Enum::Foo(a: 3, b: 4);
+   |                        ^ expected expression
+   |
+help: if this is a parameter, remove the name for the parameter
+   |
+LL -     let x = Enum::Foo(a: 3, b: 4);
+LL +     let x = Enum::Foo(3, b: 4);
+   |
+
+error: expected one of `!`, `)`, `,`, `.`, `::`, `?`, `{`, or an operator, found `:`
+  --> $DIR/recover-from-bad-variant.rs:7:24
    |
 LL |     let x = Enum::Foo(a: 3, b: 4);
-   |             ^^^^^^^^^^^^^^^^^^^^^
+   |                        ^
+   |                        |
+   |                        expected one of 8 possible tokens
+   |                        help: missing `,`
+
+error: expected expression, found `:`
+  --> $DIR/recover-from-bad-variant.rs:7:30
    |
-help: if `Enum::Foo` is a struct, use braces as delimiters
+LL |     let x = Enum::Foo(a: 3, b: 4);
+   |                              ^ expected expression
    |
-LL |     let x = Enum::Foo { a: 3, b: 4 };
-   |                       ~            ~
-help: if `Enum::Foo` is a function, use the arguments directly
+help: if this is a parameter, remove the name for the parameter
    |
 LL -     let x = Enum::Foo(a: 3, b: 4);
-LL +     let x = Enum::Foo(3, 4);
+LL +     let x = Enum::Foo(a: 3, 4);
+   |
+
+error: expected one of `!`, `)`, `,`, `.`, `::`, `?`, `{`, or an operator, found `:`
+  --> $DIR/recover-from-bad-variant.rs:7:30
    |
+LL |     let x = Enum::Foo(a: 3, b: 4);
+   |                              ^
+   |                              |
+   |                              expected one of 8 possible tokens
+   |                              help: missing `,`
+
+error[E0425]: cannot find value `a` in this scope
+  --> $DIR/recover-from-bad-variant.rs:7:23
+   |
+LL |     let x = Enum::Foo(a: 3, b: 4);
+   |                       ^ not found in this scope
+
+error[E0425]: cannot find value `b` in this scope
+  --> $DIR/recover-from-bad-variant.rs:7:29
+   |
+LL |     let x = Enum::Foo(a: 3, b: 4);
+   |                             ^ not found in this scope
+
+error[E0533]: expected value, found struct variant `Enum::Foo`
+  --> $DIR/recover-from-bad-variant.rs:7:13
+   |
+LL |     let x = Enum::Foo(a: 3, b: 4);
+   |             ^^^^^^^^^ not a value
 
 error[E0164]: expected tuple struct or tuple variant, found struct variant `Enum::Foo`
   --> $DIR/recover-from-bad-variant.rs:10:9
@@ -31,7 +75,7 @@ help: use the tuple variant pattern syntax instead
 LL |         Enum::Bar(a, b) => {}
    |                  ~~~~~~
 
-error: aborting due to 3 previous errors
+error: aborting due to 9 previous errors
 
-Some errors have detailed explanations: E0164, E0769.
+Some errors have detailed explanations: E0164, E0425, E0533, E0769.
 For more information about an error, try `rustc --explain E0164`.

tests/ui/type/type-ascription-precedence.stderr

@@ -9,12 +9,24 @@ error: expected identifier, found `:`
    |
 LL |     *(S: Z);
    |        ^ expected identifier
+   |
+help: if this is a parameter, remove the name for the parameter
+   |
+LL -     *(S: Z);
+LL +     *(Z);
+   |
 
 error: expected identifier, found `:`
   --> $DIR/type-ascription-precedence.rs:37:8
    |
 LL |     -(S: Z);
    |        ^ expected identifier
+   |
+help: if this is a parameter, remove the name for the parameter
+   |
+LL -     -(S: Z);
+LL +     -(Z);
+   |
 
 error: expected one of `.`, `;`, `?`, `}`, or an operator, found `:`
   --> $DIR/type-ascription-precedence.rs:41:12
@@ -42,5 +54,27 @@ error: expected one of `.`, `;`, `?`, `}`, or an operator, found `:`
 LL |     (S .. S): S;
    |             ^ expected one of `.`, `;`, `?`, `}`, or an operator
 
-error: aborting due to 7 previous errors
+error[E0614]: type `Z` cannot be dereferenced
+  --> $DIR/type-ascription-precedence.rs:33:5
+   |
+LL |     *(S: Z);
+   |     ^^^^^^^
+
+error[E0600]: cannot apply unary operator `-` to type `Z`
+  --> $DIR/type-ascription-precedence.rs:37:5
+   |
+LL |     -(S: Z);
+   |     ^^^^^^^ cannot apply unary operator `-`
+   |
+note: an implementation of `std::ops::Neg` might be missing for `Z`
+  --> $DIR/type-ascription-precedence.rs:7:1
+   |
+LL | struct Z;
+   | ^^^^^^^^ must implement `std::ops::Neg`
+note: the trait `std::ops::Neg` must be implemented
+  --> $SRC_DIR/core/src/ops/arith.rs:LL:COL
+
+error: aborting due to 9 previous errors
 
+Some errors have detailed explanations: E0600, E0614.
+For more information about an error, try `rustc --explain E0600`.