Rollup merge of rust-lang#67148 - Centril:ty-polish, r=estebank

 Refactor type & bounds parsing thoroughly

PR is based on rust-lang#67131 with first one from this PR being ` extract parse_ty_tuple_or_parens`.

Also fixes rust-lang#67146.

r? @estebank

src/librustc_parse/parser/expr.rs

@@ -91,6 +91,10 @@ impl<'a> Parser<'a> {
         self.parse_expr_res(Restrictions::empty(), None)
     }
 
+    pub(super) fn parse_anon_const_expr(&mut self) -> PResult<'a, AnonConst> {
+        self.parse_expr().map(|value| AnonConst { id: DUMMY_NODE_ID, value })
+    }
+
     fn parse_paren_expr_seq(&mut self) -> PResult<'a, Vec<P<Expr>>> {
         self.parse_paren_comma_seq(|p| {
             match p.parse_expr() {
@@ -883,10 +887,7 @@ impl<'a> Parser<'a> {
                     let first_expr = self.parse_expr()?;
                     if self.eat(&token::Semi) {
                         // Repeating array syntax: `[ 0; 512 ]`
-                        let count = AnonConst {
-                            id: DUMMY_NODE_ID,
-                            value: self.parse_expr()?,
-                        };
+                        let count = self.parse_anon_const_expr()?;
                         self.expect(&token::CloseDelim(token::Bracket))?;
                         ex = ExprKind::Repeat(first_expr, count);
                     } else if self.eat(&token::Comma) {

src/librustc_parse/parser/item.rs

@@ -5,7 +5,7 @@ use crate::maybe_whole;
 
 use rustc_errors::{PResult, Applicability, DiagnosticBuilder, StashKey};
 use rustc_error_codes::*;
-use syntax::ast::{self, DUMMY_NODE_ID, Ident, Attribute, AttrKind, AttrStyle, AnonConst, Item};
+use syntax::ast::{self, DUMMY_NODE_ID, Ident, Attribute, AttrKind, AttrStyle, Item};
 use syntax::ast::{AssocItem, AssocItemKind, ItemKind, UseTree, UseTreeKind};
 use syntax::ast::{PathSegment, IsAuto, Constness, IsAsync, Unsafety, Defaultness, Extern, StrLit};
 use syntax::ast::{Visibility, VisibilityKind, Mutability, FnHeader, ForeignItem, ForeignItemKind};
@@ -1318,10 +1318,7 @@ impl<'a> Parser<'a> {
         };
 
         let disr_expr = if self.eat(&token::Eq) {
-            Some(AnonConst {
-                id: DUMMY_NODE_ID,
-                value: self.parse_expr()?,
-            })
+            Some(self.parse_anon_const_expr()?)
         } else {
             None
         };

src/test/ui/issues/issue-58857.rs

@@ -2,6 +2,6 @@ struct Conj<A> {a : A}
 trait Valid {}
 
 impl<A: !Valid> Conj<A>{}
-//~^ ERROR negative trait bounds are not supported
+//~^ ERROR negative bounds are not supported
 
 fn main() {}

src/test/ui/issues/issue-58857.stderr

@@ -1,10 +1,8 @@
-error: negative trait bounds are not supported
+error: negative bounds are not supported
   --> $DIR/issue-58857.rs:4:7
    |
 LL | impl<A: !Valid> Conj<A>{}
-   |       ^^^^^^^^ negative trait bounds are not supported
-   |
-   = help: remove the trait bound
+   |       ^^^^^^^^ negative bounds are not supported
 
 error: aborting due to previous error
 

src/test/ui/parser/issue-33418.fixed

@@ -1,15 +1,15 @@
 // run-rustfix
 
 trait Tr {}
-//~^ ERROR negative trait bounds are not supported
+//~^ ERROR negative bounds are not supported
 trait Tr2: SuperA {}
-//~^ ERROR negative trait bounds are not supported
+//~^ ERROR negative bounds are not supported
 trait Tr3: SuperB {}
-//~^ ERROR negative trait bounds are not supported
+//~^ ERROR negative bounds are not supported
 trait Tr4: SuperB + SuperD {}
-//~^ ERROR negative trait bounds are not supported
+//~^ ERROR negative bounds are not supported
 trait Tr5 {}
-//~^ ERROR negative trait bounds are not supported
+//~^ ERROR negative bounds are not supported
 
 trait SuperA {}
 trait SuperB {}

src/test/ui/parser/issue-33418.rs

@@ -1,17 +1,17 @@
 // run-rustfix
 
 trait Tr: !SuperA {}
-//~^ ERROR negative trait bounds are not supported
+//~^ ERROR negative bounds are not supported
 trait Tr2: SuperA + !SuperB {}
-//~^ ERROR negative trait bounds are not supported
+//~^ ERROR negative bounds are not supported
 trait Tr3: !SuperA + SuperB {}
-//~^ ERROR negative trait bounds are not supported
+//~^ ERROR negative bounds are not supported
 trait Tr4: !SuperA + SuperB
     + !SuperC + SuperD {}
-//~^ ERROR negative trait bounds are not supported
+//~^ ERROR negative bounds are not supported
 trait Tr5: !SuperA
     + !SuperB {}
-//~^ ERROR negative trait bounds are not supported
+//~^ ERROR negative bounds are not supported
 
 trait SuperA {}
 trait SuperB {}

src/test/ui/parser/issue-33418.stderr

@@ -1,46 +1,36 @@
-error: negative trait bounds are not supported
+error: negative bounds are not supported
   --> $DIR/issue-33418.rs:3:9
    |
 LL | trait Tr: !SuperA {}
-   |         ^^^^^^^^^ negative trait bounds are not supported
-   |
-   = help: remove the trait bound
+   |         ^^^^^^^^^ negative bounds are not supported
 
-error: negative trait bounds are not supported
+error: negative bounds are not supported
   --> $DIR/issue-33418.rs:5:19
    |
 LL | trait Tr2: SuperA + !SuperB {}
-   |                   ^^^^^^^^^ negative trait bounds are not supported
-   |
-   = help: remove the trait bound
+   |                   ^^^^^^^^^ negative bounds are not supported
 
-error: negative trait bounds are not supported
+error: negative bounds are not supported
   --> $DIR/issue-33418.rs:7:10
    |
 LL | trait Tr3: !SuperA + SuperB {}
-   |          ^^^^^^^^^ negative trait bounds are not supported
-   |
-   = help: remove the trait bound
+   |          ^^^^^^^^^ negative bounds are not supported
 
-error: negative trait bounds are not supported
+error: negative bounds are not supported
   --> $DIR/issue-33418.rs:9:10
    |
 LL | trait Tr4: !SuperA + SuperB
    |          ^^^^^^^^^
 LL |     + !SuperC + SuperD {}
-   |     ^^^^^^^^^ negative trait bounds are not supported
-   |
-   = help: remove the trait bounds
+   |     ^^^^^^^^^ negative bounds are not supported
 
-error: negative trait bounds are not supported
+error: negative bounds are not supported
   --> $DIR/issue-33418.rs:12:10
    |
 LL | trait Tr5: !SuperA
    |          ^^^^^^^^^
 LL |     + !SuperB {}
-   |     ^^^^^^^^^ negative trait bounds are not supported
-   |
-   = help: remove the trait bounds
+   |     ^^^^^^^^^ negative bounds are not supported
 
 error: aborting due to 5 previous errors
 

src/test/ui/parser/issue-67146-negative-outlives-bound-syntactic-fail.rs

@@ -0,0 +1,12 @@
+// In this regression test for #67146, we check that the
+// negative outlives bound `!'a` is rejected by the parser.
+// This regression was first introduced in PR #57364.
+
+fn main() {}
+
+fn f1<T: !'static>() {}
+//~^ ERROR negative bounds are not supported
+fn f2<'a, T: Ord + !'a>() {}
+//~^ ERROR negative bounds are not supported
+fn f3<'a, T: !'a + Ord>() {}
+//~^ ERROR negative bounds are not supported

src/test/ui/parser/issue-67146-negative-outlives-bound-syntactic-fail.stderr

@@ -0,0 +1,20 @@
+error: negative bounds are not supported
+  --> $DIR/issue-67146-negative-outlives-bound-syntactic-fail.rs:7:8
+   |
+LL | fn f1<T: !'static>() {}
+   |        ^^^^^^^^^^ negative bounds are not supported
+
+error: negative bounds are not supported
+  --> $DIR/issue-67146-negative-outlives-bound-syntactic-fail.rs:9:18
+   |
+LL | fn f2<'a, T: Ord + !'a>() {}
+   |                  ^^^^^ negative bounds are not supported
+
+error: negative bounds are not supported
+  --> $DIR/issue-67146-negative-outlives-bound-syntactic-fail.rs:11:12
+   |
+LL | fn f3<'a, T: !'a + Ord>() {}
+   |            ^^^^^ negative bounds are not supported
+
+error: aborting due to 3 previous errors
+

src/test/ui/type/ascription/issue-47666.stderr

@@ -11,7 +11,7 @@ LL |     let _ = Option:Some(vec![0, 1]);
    |
    = note: `#![feature(type_ascription)]` lets you annotate an expression with a type: `<expr>: <type>`
    = note: for more information, see https://github.com/rust-lang/rust/issues/23416
-   = note: this warning originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
 
 error: aborting due to previous error