Add suggestions for possible missing fn, struct, or enum keywords

tests/ui/did_you_mean/issue-40006.rs

@@ -5,7 +5,7 @@ impl dyn A {
 struct S;
 
 trait X {
-    X() {} //~ ERROR expected one of `!` or `::`, found `(`
+    X() {} //~ ERROR missing `fn` for function definition
     fn xxx() { ### }
     L = M;
     Z = { 2 + 3 };
@@ -13,7 +13,7 @@ trait X {
 }
 
 trait A {
-    X() {} //~ ERROR expected one of `!` or `::`, found `(`
+    X() {} //~ ERROR missing `fn` for function definition
 }
 trait B {
     fn xxx() { ### } //~ ERROR expected

tests/ui/did_you_mean/issue-40006.stderr

@@ -11,26 +11,36 @@ LL | }
    | unexpected token
    | the item list ends here
 
-error: expected one of `!` or `::`, found `(`
-  --> $DIR/issue-40006.rs:8:6
+error: missing `fn` for function definition
+  --> $DIR/issue-40006.rs:8:5
    |
 LL | trait X {
    |         - while parsing this item list starting here
 LL |     X() {}
-   |      ^ expected one of `!` or `::`
+   |     ^
 ...
 LL | }
    | - the item list ends here
+   |
+help: add `fn` here to parse `X` as a function
+   |
+LL |     fn X() {}
+   |     ++
 
-error: expected one of `!` or `::`, found `(`
-  --> $DIR/issue-40006.rs:16:6
+error: missing `fn` for function definition
+  --> $DIR/issue-40006.rs:16:5
    |
 LL | trait A {
    |         - while parsing this item list starting here
 LL |     X() {}
-   |      ^ expected one of `!` or `::`
+   |     ^
 LL | }
    | - the item list ends here
+   |
+help: add `fn` here to parse `X` as a function
+   |
+LL |     fn X() {}
+   |     ++
 
 error: expected one of `!` or `[`, found `#`
   --> $DIR/issue-40006.rs:19:17
@@ -69,17 +79,17 @@ LL | }
    | - the item list ends here
 
 error: missing `fn` for method definition
-  --> $DIR/issue-40006.rs:32:8
+  --> $DIR/issue-40006.rs:32:5
    |
 LL | impl S {
    |        - while parsing this item list starting here
 LL |     pub hello_method(&self) {
-   |        ^
+   |     ^^^^^^^^^^^^^^^^
 ...
 LL | }
    | - the item list ends here
    |
-help: add `fn` here to parse `hello_method` as a public method
+help: add `fn` here to parse `hello_method` as a method
    |
 LL |     pub fn hello_method(&self) {
    |         ++

tests/ui/mismatched_types/recovered-block.rs

@@ -10,6 +10,6 @@ pub fn foo() -> Foo {
 
     pub Foo { text }
 }
-//~^^ ERROR missing `struct` for struct definition
+//~^^ ERROR missing `enum` for enum definition
 
 fn main() {}

tests/ui/mismatched_types/recovered-block.stderr

@@ -1,13 +1,13 @@
-error: missing `struct` for struct definition
-  --> $DIR/recovered-block.rs:11:8
+error: missing `enum` for enum definition
+  --> $DIR/recovered-block.rs:11:5
    |
 LL |     pub Foo { text }
-   |        ^
+   |     ^^^^^^^
    |
-help: add `struct` here to parse `Foo` as a public struct
+help: add `enum` here to parse `Foo` as an enum
    |
-LL |     pub struct Foo { text }
-   |         ++++++
+LL |     pub enum Foo { text }
+   |         ++++
 
 error: aborting due to 1 previous error
 

tests/ui/parser/extern-no-fn.rs

@@ -1,5 +1,7 @@
 extern "C" {
-    f(); //~ ERROR expected one of `!` or `::`, found `(`
+    f();
+    //~^ ERROR missing `fn` or `struct` for function or struct definition
+    //~| HELP if you meant to call a macro, try
 }
 
 fn main() {

tests/ui/parser/extern-no-fn.stderr

@@ -1,12 +1,18 @@
-error: expected one of `!` or `::`, found `(`
-  --> $DIR/extern-no-fn.rs:2:6
+error: missing `fn` or `struct` for function or struct definition
+  --> $DIR/extern-no-fn.rs:2:5
    |
 LL | extern "C" {
    |            - while parsing this item list starting here
 LL |     f();
-   |      ^ expected one of `!` or `::`
+   |     ^
+...
 LL | }
    | - the item list ends here
+   |
+help: if you meant to call a macro, try
+   |
+LL |     f!();
+   |     ~~
 
 error: aborting due to 1 previous error
 

tests/ui/parser/missing-enum-issue-125446.rs

@@ -0,0 +1,6 @@
+Whoops {
+//~^ ERROR missing `enum` for enum definition
+//~| HELP add `enum` here to parse `Whoops` as an enum
+    OptionA,
+    OptionB,
+}

tests/ui/parser/missing-enum-issue-125446.stderr

@@ -0,0 +1,13 @@
+error: missing `enum` for enum definition
+  --> $DIR/missing-enum-issue-125446.rs:1:1
+   |
+LL | Whoops {
+   | ^^^^^^
+   |
+help: add `enum` here to parse `Whoops` as an enum
+   |
+LL | enum Whoops {
+   | ++++
+
+error: aborting due to 1 previous error
+

tests/ui/parser/missing-enum-or-struct-issue-125446.rs

@@ -0,0 +1,2 @@
+Whoops {}
+//~^ ERROR missing `enum` or `struct` for enum or struct definition

tests/ui/parser/missing-enum-or-struct-issue-125446.stderr

@@ -0,0 +1,8 @@
+error: missing `enum` or `struct` for enum or struct definition
+  --> $DIR/missing-enum-or-struct-issue-125446.rs:1:1
+   |
+LL | Whoops {}
+   | ^^^^^^
+
+error: aborting due to 1 previous error
+

tests/ui/parser/missing-fn-issue-125446.rs

@@ -0,0 +1,7 @@
+whoops() {}
+//~^ ERROR missing `fn` for function definition
+//~| HELP add `fn` here to parse `whoops` as a function
+
+fn main() {
+    whoops();
+}

tests/ui/parser/missing-fn-issue-125446.stderr

@@ -0,0 +1,13 @@
+error: missing `fn` for function definition
+  --> $DIR/missing-fn-issue-125446.rs:1:1
+   |
+LL | whoops() {}
+   | ^^^^^^
+   |
+help: add `fn` here to parse `whoops` as a function
+   |
+LL | fn whoops() {}
+   | ++
+
+error: aborting due to 1 previous error
+

tests/ui/parser/missing-fn-issue-65381-1.rs

@@ -0,0 +1,4 @@
+main() {
+//~^ ERROR missing `fn` for function definition
+//~| HELP add `fn` here to parse `main` as a function
+}

tests/ui/parser/missing-fn-issue-65381-1.stderr

@@ -0,0 +1,13 @@
+error: missing `fn` for function definition
+  --> $DIR/missing-fn-issue-65381-1.rs:1:1
+   |
+LL | main() {
+   | ^^^^
+   |
+help: add `fn` here to parse `main` as a function
+   |
+LL | fn main() {
+   | ++
+
+error: aborting due to 1 previous error
+

tests/ui/parser/missing-fn-issue-65381-2.rs

@@ -0,0 +1,3 @@
+main();
+//~^ ERROR missing `fn` or `struct` for function or struct definition
+//~| HELP if you meant to call a macro, try

tests/ui/parser/missing-fn-issue-65381-2.stderr

@@ -0,0 +1,13 @@
+error: missing `fn` or `struct` for function or struct definition
+  --> $DIR/missing-fn-issue-65381-2.rs:1:1
+   |
+LL | main();
+   | ^^^^
+   |
+help: if you meant to call a macro, try
+   |
+LL | main!();
+   | ~~~~~
+
+error: aborting due to 1 previous error
+

tests/ui/parser/missing-fn-issue-65381-3.rs

@@ -0,0 +1,4 @@
+pub const initial_value() -> Self {
+//~^ ERROR missing `fn` for function definition
+//~| HELP add `fn` here to parse `initial_value` as a function
+}

tests/ui/parser/missing-fn-issue-65381-3.stderr

@@ -0,0 +1,13 @@
+error: missing `fn` for function definition
+  --> $DIR/missing-fn-issue-65381-3.rs:1:11
+   |
+LL | pub const initial_value() -> Self {
+   |           ^^^^^^^^^^^^^
+   |
+help: add `fn` here to parse `initial_value` as a function
+   |
+LL | pub const fn initial_value() -> Self {
+   |           ++
+
+error: aborting due to 1 previous error
+

tests/ui/parser/missing-struct-issue-125446.rs

@@ -0,0 +1,5 @@
+Whoops {
+//~^ ERROR missing `struct` for struct definition
+//~| HELP add `struct` here to parse `Whoops` as a struct
+    value: u64,
+}

tests/ui/parser/missing-struct-issue-125446.stderr

@@ -0,0 +1,13 @@
+error: missing `struct` for struct definition
+  --> $DIR/missing-struct-issue-125446.rs:1:1
+   |
+LL | Whoops {
+   | ^^^^^^
+   |
+help: add `struct` here to parse `Whoops` as a struct
+   |
+LL | struct Whoops {
+   | ++++++
+
+error: aborting due to 1 previous error
+

tests/ui/pub/pub-ident-fn-2.stderr

@@ -1,10 +1,10 @@
 error: missing `fn` for function definition
-  --> $DIR/pub-ident-fn-2.rs:3:4
+  --> $DIR/pub-ident-fn-2.rs:3:1
    |
 LL | pub foo(_s: usize) { bar() }
-   |    ^
+   | ^^^^^^^
    |
-help: add `fn` here to parse `foo` as a public function
+help: add `fn` here to parse `foo` as a function
    |
 LL | pub fn foo(_s: usize) { bar() }
    |     ++

tests/ui/pub/pub-ident-fn-or-struct.stderr

@@ -1,8 +1,13 @@
 error: missing `fn` or `struct` for function or struct definition
-  --> $DIR/pub-ident-fn-or-struct.rs:1:4
+  --> $DIR/pub-ident-fn-or-struct.rs:1:1
    |
 LL | pub S (foo) bar
-   | ---^- help: if you meant to call a macro, try: `S!`
+   | ^^^^^
+   |
+help: if you meant to call a macro, try
+   |
+LL | pub S! (foo) bar
+   |     ~~
 
 error: aborting due to 1 previous error
 

tests/ui/pub/pub-ident-fn-with-lifetime-2.rs

@@ -1,4 +1,4 @@
-pub   bar<'a>(&self, _s: &'a usize) -> bool { true }
+pub bar<'a>(&self, _s: &'a usize) -> bool { true }
 //~^ ERROR missing `fn` for method definition
 
 fn main() {

tests/ui/pub/pub-ident-fn-with-lifetime-2.stderr

@@ -1,10 +1,10 @@
 error: missing `fn` for method definition
-  --> $DIR/pub-ident-fn-with-lifetime-2.rs:1:4
+  --> $DIR/pub-ident-fn-with-lifetime-2.rs:1:1
    |
-LL | pub   bar<'a>(&self, _s: &'a usize) -> bool { true }
-   |    ^^^
+LL | pub bar<'a>(&self, _s: &'a usize) -> bool { true }
+   | ^^^^^^^
    |
-help: add `fn` here to parse `bar` as a public method
+help: add `fn` here to parse `bar` as a method
    |
 LL | pub fn bar<'a>(&self, _s: &'a usize) -> bool { true }
    |     ++

tests/ui/pub/pub-ident-fn-with-lifetime.rs

@@ -1,6 +1,6 @@
 //@ run-rustfix
 
-pub   foo<'a>(_s: &'a usize) -> bool { true }
+pub foo<'a>(_s: &'a usize) -> bool { true }
 //~^ ERROR missing `fn` for function definition
 
 fn main() {

tests/ui/pub/pub-ident-fn-with-lifetime.stderr

@@ -1,10 +1,10 @@
 error: missing `fn` for function definition
-  --> $DIR/pub-ident-fn-with-lifetime.rs:3:4
+  --> $DIR/pub-ident-fn-with-lifetime.rs:3:1
    |
-LL | pub   foo<'a>(_s: &'a usize) -> bool { true }
-   |    ^^^
+LL | pub foo<'a>(_s: &'a usize) -> bool { true }
+   | ^^^^^^^
    |
-help: add `fn` here to parse `foo` as a public function
+help: add `fn` here to parse `foo` as a function
    |
 LL | pub fn foo<'a>(_s: &'a usize) -> bool { true }
    |     ++

tests/ui/pub/pub-ident-fn.rs

@@ -1,6 +1,6 @@
 //@ run-rustfix
 
-pub   foo(_s: usize) -> bool { true }
+pub foo(_s: usize) -> bool { true }
 //~^ ERROR missing `fn` for function definition
 
 fn main() {

tests/ui/pub/pub-ident-fn.stderr

@@ -1,10 +1,10 @@
 error: missing `fn` for function definition
-  --> $DIR/pub-ident-fn.rs:3:4
+  --> $DIR/pub-ident-fn.rs:3:1
    |
-LL | pub   foo(_s: usize) -> bool { true }
-   |    ^^^
+LL | pub foo(_s: usize) -> bool { true }
+   | ^^^^^^^
    |
-help: add `fn` here to parse `foo` as a public function
+help: add `fn` here to parse `foo` as a function
    |
 LL | pub fn foo(_s: usize) -> bool { true }
    |     ++

tests/ui/pub/pub-ident-struct-2.stderr

@@ -1,10 +1,10 @@
 error: missing `struct` for struct definition
-  --> $DIR/pub-ident-struct-2.rs:4:8
+  --> $DIR/pub-ident-struct-2.rs:4:5
    |
 LL |     pub bar();
-   |        ^
+   |     ^^^^^^^
    |
-help: add `struct` here to parse `bar` as a public struct
+help: add `struct` here to parse `bar` as a struct
    |
 LL |     pub struct bar();
    |         ++++++

tests/ui/pub/pub-ident-struct-3.stderr

@@ -1,10 +1,10 @@
 error: missing `struct` for struct definition
-  --> $DIR/pub-ident-struct-3.rs:1:4
+  --> $DIR/pub-ident-struct-3.rs:1:1
    |
 LL | pub S();
-   |    ^
+   | ^^^^^
    |
-help: add `struct` here to parse `S` as a public struct
+help: add `struct` here to parse `S` as a struct
    |
 LL | pub struct S();
    |     ++++++

tests/ui/pub/pub-ident-struct-4.stderr

@@ -1,10 +1,10 @@
 error: missing `struct` for struct definition
-  --> $DIR/pub-ident-struct-4.rs:4:4
+  --> $DIR/pub-ident-struct-4.rs:4:1
    |
 LL | pub T(String);
-   |    ^
+   | ^^^^^
    |
-help: add `struct` here to parse `T` as a public struct
+help: add `struct` here to parse `T` as a struct
    |
 LL | pub struct T(String);
    |     ++++++

tests/ui/pub/pub-ident-struct-with-lifetime.rs

@@ -1,4 +1,4 @@
 pub S<'a> {
-//~^ ERROR missing `struct` for struct definition
+//~^ ERROR missing `enum` or `struct` for enum or struct definition
 }
 fn main() {}

tests/ui/pub/pub-ident-struct-with-lifetime.stderr

@@ -1,13 +1,8 @@
-error: missing `struct` for struct definition
-  --> $DIR/pub-ident-struct-with-lifetime.rs:1:4
+error: missing `enum` or `struct` for enum or struct definition
+  --> $DIR/pub-ident-struct-with-lifetime.rs:1:1
    |
 LL | pub S<'a> {
-   |    ^
-   |
-help: add `struct` here to parse `S` as a public struct
-   |
-LL | pub struct S<'a> {
-   |     ++++++
+   | ^^^^^
 
 error: aborting due to 1 previous error
 

tests/ui/pub/pub-ident-struct.fixed

@@ -1,6 +0,0 @@
-//@ run-rustfix
-
-pub struct S {
-//~^ ERROR missing `struct` for struct definition
-}
-fn main() {}

tests/ui/pub/pub-ident-struct.rs

@@ -1,6 +1,4 @@
-//@ run-rustfix
-
 pub S {
-//~^ ERROR missing `struct` for struct definition
+//~^ ERROR missing `enum` or `struct` for enum or struct definition
 }
 fn main() {}

tests/ui/pub/pub-ident-struct.stderr

@@ -1,13 +1,8 @@
-error: missing `struct` for struct definition
-  --> $DIR/pub-ident-struct.rs:3:4
+error: missing `enum` or `struct` for enum or struct definition
+  --> $DIR/pub-ident-struct.rs:1:1
    |
 LL | pub S {
-   |    ^
-   |
-help: add `struct` here to parse `S` as a public struct
-   |
-LL | pub struct S {
-   |     ++++++
+   | ^^^^^
 
 error: aborting due to 1 previous error
 

tests/ui/pub/pub-ident-with-lifetime-incomplete.rs

@@ -1,5 +1,5 @@
 fn main() {
 }
 
-pub   foo<'a>
+pub foo<'a>
 //~^ ERROR missing `fn` or `struct` for function or struct definition

tests/ui/pub/pub-ident-with-lifetime-incomplete.stderr

@@ -1,8 +1,8 @@
 error: missing `fn` or `struct` for function or struct definition
-  --> $DIR/pub-ident-with-lifetime-incomplete.rs:4:4
+  --> $DIR/pub-ident-with-lifetime-incomplete.rs:4:1
    |
-LL | pub   foo<'a>
-   |    ^^^
+LL | pub foo<'a>
+   | ^^^^^^^
 
 error: aborting due to 1 previous error
 

tests/ui/track-diagnostics/track4.stderr

@@ -1,14 +1,14 @@
-error: missing `struct` for struct definition
+error: missing `enum` for enum definition
   --> $DIR/track4.rs:LL:CC
    |
 LL | pub onion {
-   |    ^
+   | ^^^^^^^^^
 -Ztrack-diagnostics: created at compiler/rustc_parse/src/parser/item.rs:LL:CC
    |
-help: add `struct` here to parse `onion` as a public struct
+help: add `enum` here to parse `onion` as an enum
    |
-LL | pub struct onion {
-   |     ++++++
+LL | pub enum onion {
+   |     ++++
 
 error: aborting due to 1 previous error