Rollup merge of #107602 - estebank:anon-enum-access, r=compiler-errors

Parse and recover from type ascription in patterns

Reintroduce part of #106960, which was reverted in #107478.

r? `@compiler-errors`

4 files changed, 125 insertions, 27 deletions

diff --git a/tests/ui/parser/issues/issue-87086-colon-path-sep.rs b/tests/ui/parser/issues/issue-87086-colon-path-sep.rs
index 0b7b67496d6..e1ea38f2795 100644
--- a/tests/ui/parser/issues/issue-87086-colon-path-sep.rs
+++ b/tests/ui/parser/issues/issue-87086-colon-path-sep.rs
@@ -68,7 +68,6 @@ fn main() {
         Foo:Bar::Baz => {}
         //~^ ERROR: expected one of
         //~| HELP: maybe write a path separator here
-        //~| ERROR: failed to resolve: `Bar` is a variant, not a module
     }
     match myfoo {
         Foo::Bar => {}
diff --git a/tests/ui/parser/issues/issue-87086-colon-path-sep.stderr b/tests/ui/parser/issues/issue-87086-colon-path-sep.stderr
index 2050a16beb3..63b072ac4cd 100644
--- a/tests/ui/parser/issues/issue-87086-colon-path-sep.stderr
+++ b/tests/ui/parser/issues/issue-87086-colon-path-sep.stderr
@@ -2,89 +2,118 @@ error: expected one of `@` or `|`, found `:`
   --> $DIR/issue-87086-colon-path-sep.rs:17:12
    |
 LL |         Foo:Bar => {}
-   |            ^
+   |            ^--- specifying the type of a pattern isn't supported
    |            |
    |            expected one of `@` or `|`
-   |            help: maybe write a path separator here: `::`
+   |
+help: maybe write a path separator here
+   |
+LL |         Foo::Bar => {}
+   |            ~~
 
 error: expected one of `!`, `(`, `...`, `..=`, `..`, `::`, `{`, or `|`, found `:`
   --> $DIR/issue-87086-colon-path-sep.rs:23:17
    |
 LL |         qux::Foo:Bar => {}
-   |                 ^
+   |                 ^--- specifying the type of a pattern isn't supported
    |                 |
    |                 expected one of 8 possible tokens
-   |                 help: maybe write a path separator here: `::`
+   |
+help: maybe write a path separator here
+   |
+LL |         qux::Foo::Bar => {}
+   |                 ~~
 
 error: expected one of `@` or `|`, found `:`
   --> $DIR/issue-87086-colon-path-sep.rs:29:12
    |
 LL |         qux:Foo::Baz => {}
-   |            ^
+   |            ^-------- specifying the type of a pattern isn't supported
    |            |
    |            expected one of `@` or `|`
-   |            help: maybe write a path separator here: `::`
+   |
+help: maybe write a path separator here
+   |
+LL |         qux::Foo::Baz => {}
+   |            ~~
 
 error: expected one of `@` or `|`, found `:`
   --> $DIR/issue-87086-colon-path-sep.rs:35:12
    |
 LL |         qux: Foo::Baz if true => {}
-   |            ^
+   |            ^ -------- specifying the type of a pattern isn't supported
    |            |
    |            expected one of `@` or `|`
-   |            help: maybe write a path separator here: `::`
+   |
+help: maybe write a path separator here
+   |
+LL |         qux::Foo::Baz if true => {}
+   |            ~~
 
 error: expected one of `@` or `|`, found `:`
   --> $DIR/issue-87086-colon-path-sep.rs:40:15
    |
 LL |     if let Foo:Bar = f() {
-   |               ^
+   |               ^--- specifying the type of a pattern isn't supported
    |               |
    |               expected one of `@` or `|`
-   |               help: maybe write a path separator here: `::`
+   |
+help: maybe write a path separator here
+   |
+LL |     if let Foo::Bar = f() {
+   |               ~~
 
 error: expected one of `@` or `|`, found `:`
   --> $DIR/issue-87086-colon-path-sep.rs:48:16
    |
 LL |         ref qux: Foo::Baz => {}
-   |                ^
+   |                ^ -------- specifying the type of a pattern isn't supported
    |                |
    |                expected one of `@` or `|`
-   |                help: maybe write a path separator here: `::`
+   |
+help: maybe write a path separator here
+   |
+LL |         ref qux::Foo::Baz => {}
+   |                ~~
 
 error: expected one of `@` or `|`, found `:`
   --> $DIR/issue-87086-colon-path-sep.rs:57:16
    |
 LL |         mut qux: Foo::Baz => {}
-   |                ^
+   |                ^ -------- specifying the type of a pattern isn't supported
    |                |
    |                expected one of `@` or `|`
-   |                help: maybe write a path separator here: `::`
+   |
+help: maybe write a path separator here
+   |
+LL |         mut qux::Foo::Baz => {}
+   |                ~~
 
 error: expected one of `@` or `|`, found `:`
   --> $DIR/issue-87086-colon-path-sep.rs:68:12
    |
 LL |         Foo:Bar::Baz => {}
-   |            ^
+   |            ^-------- specifying the type of a pattern isn't supported
    |            |
    |            expected one of `@` or `|`
-   |            help: maybe write a path separator here: `::`
+   |
+help: maybe write a path separator here
+   |
+LL |         Foo::Bar::Baz => {}
+   |            ~~
 
 error: expected one of `@` or `|`, found `:`
-  --> $DIR/issue-87086-colon-path-sep.rs:75:12
+  --> $DIR/issue-87086-colon-path-sep.rs:74:12
    |
 LL |         Foo:Bar => {}
-   |            ^
+   |            ^--- specifying the type of a pattern isn't supported
    |            |
    |            expected one of `@` or `|`
-   |            help: maybe write a path separator here: `::`
-
-error[E0433]: failed to resolve: `Bar` is a variant, not a module
-  --> $DIR/issue-87086-colon-path-sep.rs:68:13
    |
-LL |         Foo:Bar::Baz => {}
-   |             ^^^ `Bar` is a variant, not a module
+help: maybe write a path separator here
+   |
+LL |         Foo::Bar => {}
+   |            ~~
 
-error: aborting due to 10 previous errors
+error: aborting due to 9 previous errors
 
-For more information about this error, try `rustc --explain E0433`.
diff --git a/tests/ui/parser/type-ascription-in-pattern.rs b/tests/ui/parser/type-ascription-in-pattern.rs
new file mode 100644
index 00000000000..fec168afba1
--- /dev/null
+++ b/tests/ui/parser/type-ascription-in-pattern.rs
@@ -0,0 +1,16 @@
+fn foo(x: bool) -> i32 {
+    match x {
+        x: i32 => x, //~ ERROR expected
+        //~^ ERROR mismatched types
+        true => 42.,
+        false => 0.333,
+    }
+}
+
+fn main() {
+    match foo(true) {
+        42: i32 => (), //~ ERROR expected
+        _: f64 => (), //~ ERROR expected
+        x: i32 => (), //~ ERROR expected
+    }
+}
diff --git a/tests/ui/parser/type-ascription-in-pattern.stderr b/tests/ui/parser/type-ascription-in-pattern.stderr
new file mode 100644
index 00000000000..09190754993
--- /dev/null
+++ b/tests/ui/parser/type-ascription-in-pattern.stderr
@@ -0,0 +1,54 @@
+error: expected one of `@` or `|`, found `:`
+  --> $DIR/type-ascription-in-pattern.rs:3:10
+   |
+LL |         x: i32 => x,
+   |          ^ --- specifying the type of a pattern isn't supported
+   |          |
+   |          expected one of `@` or `|`
+   |
+help: maybe write a path separator here
+   |
+LL |         x::i32 => x,
+   |          ~~
+
+error: expected one of `...`, `..=`, `..`, or `|`, found `:`
+  --> $DIR/type-ascription-in-pattern.rs:12:11
+   |
+LL |         42: i32 => (),
+   |           ^ --- specifying the type of a pattern isn't supported
+   |           |
+   |           expected one of `...`, `..=`, `..`, or `|`
+
+error: expected `|`, found `:`
+  --> $DIR/type-ascription-in-pattern.rs:13:10
+   |
+LL |         _: f64 => (),
+   |          ^ --- specifying the type of a pattern isn't supported
+   |          |
+   |          expected `|`
+
+error: expected one of `@` or `|`, found `:`
+  --> $DIR/type-ascription-in-pattern.rs:14:10
+   |
+LL |         x: i32 => (),
+   |          ^ --- specifying the type of a pattern isn't supported
+   |          |
+   |          expected one of `@` or `|`
+   |
+help: maybe write a path separator here
+   |
+LL |         x::i32 => (),
+   |          ~~
+
+error[E0308]: mismatched types
+  --> $DIR/type-ascription-in-pattern.rs:3:19
+   |
+LL | fn foo(x: bool) -> i32 {
+   |                    --- expected `i32` because of return type
+LL |     match x {
+LL |         x: i32 => x,
+   |                   ^ expected `i32`, found `bool`
+
+error: aborting due to 5 previous errors
+
+For more information about this error, try `rustc --explain E0308`.