parser: misc small item related improvements & cleanups.

rust-lang · bors · Feb 14, 2020 · Feb 7, 2020 · Feb 13, 2020 · Feb 13, 2020
commit aaaf0ba072815d275820d8ac85ece6eeb9182321
diff --git a/src/librustc_parse/parser/item.rs b/src/librustc_parse/parser/item.rs
diff --git a/src/librustc_parse/parser/mod.rs b/src/librustc_parse/parser/mod.rs
@@ -572,6 +572,11 @@ impl<'a> Parser<'a> {
         if !self.eat_keyword(kw) { self.unexpected() } else { Ok(()) }
     }
 
+    /// Is the given keyword `kw` followed by a non-reserved identifier?
+    fn is_kw_followed_by_ident(&self, kw: Symbol) -> bool {
+        self.token.is_keyword(kw) && self.look_ahead(1, |t| t.is_ident() && !t.is_reserved_ident())
+    }
+
     fn check_or_expected(&mut self, ok: bool, typ: TokenType) -> bool {
         if ok {
             true

diff --git a/src/librustc_parse/parser/stmt.rs b/src/librustc_parse/parser/stmt.rs
@@ -8,7 +8,7 @@ use crate::DirectoryOwnership;
 
 use rustc_errors::{Applicability, PResult};
 use rustc_span::source_map::{BytePos, Span};
-use rustc_span::symbol::{kw, sym, Symbol};
+use rustc_span::symbol::{kw, sym};
 use syntax::ast;
 use syntax::ast::{AttrStyle, AttrVec, Attribute, Mac, MacStmtStyle};
 use syntax::ast::{Block, BlockCheckMode, Expr, ExprKind, Local, Stmt, StmtKind, DUMMY_NODE_ID};
@@ -55,13 +55,11 @@ impl<'a> Parser<'a> {
             return self.recover_stmt_local(lo, attrs.into(), msg, "let");
         }
 
-        // Starts like a simple path, being careful to avoid contextual keywords
-        // such as a union items, item with `crate` visibility or auto trait items.
-        // Our goal here is to parse an arbitrary path `a::b::c` but not something that starts
-        // like a path (1 token), but it fact not a path.
-        if self.token.is_path_start()
-            && !self.token.is_qpath_start()
-            && !self.is_path_start_item() // Confirm we don't steal syntax from `parse_item_`.
+        // Starts like a simple path, being careful to avoid contextual keywords,
+        // e.g., `union`, items with `crate` visibility, or `auto trait` items.
+        // We aim to parse an arbitrary path `a::b` but not something that starts like a path
+        // (1 token), but it fact not a path. Also, we avoid stealing syntax from `parse_item_`.
+        if self.token.is_path_start() && !self.token.is_qpath_start() && !self.is_path_start_item()
         {
             let path = self.parse_path(PathStyle::Expr)?;
 
@@ -191,10 +189,6 @@ impl<'a> Parser<'a> {
         }
     }
 
-    fn is_kw_followed_by_ident(&self, kw: Symbol) -> bool {
-        self.token.is_keyword(kw) && self.look_ahead(1, |t| t.is_ident() && !t.is_reserved_ident())
-    }
-
     fn recover_stmt_local(
         &mut self,
         lo: Span,

diff --git a/src/test/ui/issues/issue-58856-2.stderr b/src/test/ui/issues/issue-58856-2.stderr
@@ -7,11 +7,11 @@ LL |     fn how_are_you(&self -> Empty {
    |                   |     help: `)` may belong here
    |                   unclosed delimiter
 
-error: expected one of `async`, `const`, `crate`, `default`, `extern`, `fn`, `pub`, `type`, `unsafe`, or `}`, found `)`
+error: expected one of `async`, `const`, `crate`, `default`, `extern`, `fn`, `pub`, `type`, `unsafe`, `}`, or identifier, found `)`
   --> $DIR/issue-58856-2.rs:11:1
    |
 LL |     }
-   |      - expected one of 10 possible tokens
+   |      - expected one of 11 possible tokens
 LL | }
    | ^ unexpected token
 

diff --git a/src/test/ui/issues/issue-60075.stderr b/src/test/ui/issues/issue-60075.stderr
@@ -4,7 +4,7 @@ error: expected one of `.`, `;`, `?`, `else`, or an operator, found `}`
 LL |         });
    |          ^ expected one of `.`, `;`, `?`, `else`, or an operator
 
-error: expected one of `async`, `const`, `crate`, `default`, `extern`, `fn`, `pub`, `type`, `unsafe`, or `}`, found `;`
+error: expected one of `async`, `const`, `crate`, `default`, `extern`, `fn`, `pub`, `type`, `unsafe`, `}`, or identifier, found `;`
   --> $DIR/issue-60075.rs:6:11
    |
 LL |     fn qux() -> Option<usize> {

diff --git a/src/test/ui/macros/issue-54441.rs b/src/test/ui/macros/issue-54441.rs
@@ -1,6 +1,7 @@
 macro_rules! m {
+    //~^ ERROR missing `fn`, `type`, or `static` for extern-item declaration
     () => {
-        let //~ ERROR expected
+        let
     };
 }
 

diff --git a/src/test/ui/macros/issue-54441.stderr b/src/test/ui/macros/issue-54441.stderr
@@ -1,13 +1,11 @@
-error: expected one of `async`, `const`, `crate`, `extern`, `fn`, `pub`, `static`, `type`, or `unsafe`, found keyword `let`
-  --> $DIR/issue-54441.rs:3:9
+error: missing `fn`, `type`, or `static` for extern-item declaration
+  --> $DIR/issue-54441.rs:1:1
    |
-LL |         let
-   |         ^^^ expected one of 9 possible tokens
-...
-LL |     m!();
-   |     ----- in this macro invocation
-   |
-   = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
+LL | / macro_rules! m {
+LL | |
+LL | |     () => {
+LL | |         let
+   | |________^ missing `fn`, `type`, or `static`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/parser/attr-before-eof.stderr b/src/test/ui/parser/attr-before-eof.stderr
@@ -1,8 +1,8 @@
 error: expected item after attributes
-  --> $DIR/attr-before-eof.rs:3:16
+  --> $DIR/attr-before-eof.rs:3:1
    |
 LL | #[derive(Debug)]
-   |                ^
+   | ^^^^^^^^^^^^^^^^
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/parser/attr-dangling-in-mod.stderr b/src/test/ui/parser/attr-dangling-in-mod.stderr
@@ -1,8 +1,8 @@
 error: expected item after attributes
-  --> $DIR/attr-dangling-in-mod.rs:6:14
+  --> $DIR/attr-dangling-in-mod.rs:6:1
    |
 LL | #[foo = "bar"]
-   |              ^
+   | ^^^^^^^^^^^^^^
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/parser/attrs-after-extern-mod.stderr b/src/test/ui/parser/attrs-after-extern-mod.stderr
@@ -1,8 +1,8 @@
 error: expected item after attributes
-  --> $DIR/attrs-after-extern-mod.rs:6:19
+  --> $DIR/attrs-after-extern-mod.rs:6:5
    |
 LL |     #[cfg(stage37)]
-   |                   ^
+   |     ^^^^^^^^^^^^^^^
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/parser/default.rs b/src/test/ui/parser/default.rs
@@ -19,7 +19,8 @@ impl Foo for u16 {
 }
 
 impl Foo for u32 { //~ ERROR not all trait items implemented, missing: `foo`
-    default pub fn foo<T: Default>() -> T { T::default() } //~ ERROR expected one of
+    default pub fn foo<T: Default>() -> T { T::default() }
+    //~^ ERROR missing `fn`, `type`, or `const` for associated-item declaration
 }
 
 fn main() {}
diff --git a/src/test/ui/parser/default.stderr b/src/test/ui/parser/default.stderr
@@ -1,8 +1,8 @@
-error: expected one of `async`, `const`, `extern`, `fn`, `type`, or `unsafe`, found keyword `pub`
-  --> $DIR/default.rs:22:13
+error: missing `fn`, `type`, or `const` for associated-item declaration
+  --> $DIR/default.rs:22:12
    |
 LL |     default pub fn foo<T: Default>() -> T { T::default() }
-   |             ^^^ expected one of `async`, `const`, `extern`, `fn`, `type`, or `unsafe`
+   |            ^ missing `fn`, `type`, or `const`
 
 error[E0449]: unnecessary visibility qualifier
   --> $DIR/default.rs:16:5

diff --git a/src/test/ui/parser/doc-before-attr.stderr b/src/test/ui/parser/doc-before-attr.stderr
@@ -1,8 +1,10 @@
 error: expected item after attributes
-  --> $DIR/doc-before-attr.rs:4:16
+  --> $DIR/doc-before-attr.rs:4:1
    |
+LL | /// hi
+   | ------ other attributes here
 LL | #[derive(Debug)]
-   |                ^
+   | ^^^^^^^^^^^^^^^^
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/parser/duplicate-visibility.rs b/src/test/ui/parser/duplicate-visibility.rs
@@ -1,7 +1,6 @@
-// error-pattern: expected one of `(`, `async`, `const`, `extern`, `fn`
-
 fn main() {}
 
 extern {
     pub pub fn foo();
+    //~^ ERROR missing `fn`, `type`, or `static` for extern-item declaration
 }
diff --git a/src/test/ui/parser/duplicate-visibility.stderr b/src/test/ui/parser/duplicate-visibility.stderr
@@ -1,8 +1,8 @@
-error: expected one of `(`, `async`, `const`, `extern`, `fn`, `static`, `type`, or `unsafe`, found keyword `pub`
-  --> $DIR/duplicate-visibility.rs:6:9
+error: missing `fn`, `type`, or `static` for extern-item declaration
+  --> $DIR/duplicate-visibility.rs:4:8
    |
 LL |     pub pub fn foo();
-   |         ^^^ expected one of 8 possible tokens
+   |        ^ missing `fn`, `type`, or `static`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/parser/issue-19398.rs b/src/test/ui/parser/issue-19398.rs
@@ -1,5 +1,6 @@
 trait T {
-    extern "Rust" unsafe fn foo(); //~ ERROR expected one of `async`, `const`
+    //~^ ERROR missing `fn`, `type`, or `const` for associated-item declaration
+    extern "Rust" unsafe fn foo();
 }
 
 fn main() {}
diff --git a/src/test/ui/parser/issue-19398.stderr b/src/test/ui/parser/issue-19398.stderr
@@ -1,10 +1,11 @@
-error: expected one of `async`, `const`, `crate`, `default`, `extern`, `fn`, `pub`, `type`, `unsafe`, or `}`, found keyword `extern`
-  --> $DIR/issue-19398.rs:2:5
+error: missing `fn`, `type`, or `const` for associated-item declaration
+  --> $DIR/issue-19398.rs:1:10
    |
-LL | trait T {
-   |          - expected one of 10 possible tokens
-LL |     extern "Rust" unsafe fn foo();
-   |     ^^^^^^ unexpected token
+LL |   trait T {
+   |  __________^
+LL | |
+LL | |     extern "Rust" unsafe fn foo();
+   | |____^ missing `fn`, `type`, or `const`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/parser/issue-20711-2.rs b/src/test/ui/parser/issue-20711-2.rs
@@ -4,6 +4,7 @@ impl Foo {
     fn foo() {}
 
     #[stable(feature = "rust1", since = "1.0.0")]
-} //~ ERROR expected one of `async`, `const`, `crate`, `default`, `extern`, `fn`, `pub`, `type`, or
+    //~^ ERROR expected item after attributes
+}
 
 fn main() {}
diff --git a/src/test/ui/parser/issue-20711-2.stderr b/src/test/ui/parser/issue-20711-2.stderr
@@ -1,10 +1,8 @@
-error: expected one of `async`, `const`, `crate`, `default`, `extern`, `fn`, `pub`, `type`, or `unsafe`, found `}`
-  --> $DIR/issue-20711-2.rs:7:1
+error: expected item after attributes
+  --> $DIR/issue-20711-2.rs:6:5
    |
 LL |     #[stable(feature = "rust1", since = "1.0.0")]
-   |                                                  - expected one of 9 possible tokens
-LL | }
-   | ^ unexpected token
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/parser/issue-20711.rs b/src/test/ui/parser/issue-20711.rs
@@ -2,6 +2,7 @@ struct Foo;
 
 impl Foo {
     #[stable(feature = "rust1", since = "1.0.0")]
-} //~ ERROR expected one of `async`, `const`, `crate`, `default`, `extern`, `fn`, `pub`, `type`, or
+    //~^ ERROR expected item after attributes
+}
 
 fn main() {}
diff --git a/src/test/ui/parser/issue-20711.stderr b/src/test/ui/parser/issue-20711.stderr
@@ -1,10 +1,8 @@
-error: expected one of `async`, `const`, `crate`, `default`, `extern`, `fn`, `pub`, `type`, or `unsafe`, found `}`
-  --> $DIR/issue-20711.rs:5:1
+error: expected item after attributes
+  --> $DIR/issue-20711.rs:4:5
    |
 LL |     #[stable(feature = "rust1", since = "1.0.0")]
-   |                                                  - expected one of 9 possible tokens
-LL | }
-   | ^ unexpected token
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/parser/issue-32446.stderr b/src/test/ui/parser/issue-32446.stderr
@@ -1,8 +1,8 @@
-error: expected one of `async`, `const`, `crate`, `default`, `extern`, `fn`, `pub`, `type`, `unsafe`, or `}`, found `...`
+error: expected one of `async`, `const`, `crate`, `default`, `extern`, `fn`, `pub`, `type`, `unsafe`, `}`, or identifier, found `...`
   --> $DIR/issue-32446.rs:4:11
    |
 LL | trait T { ... }
-   |           ^^^ expected one of 10 possible tokens
+   |           ^^^ expected one of 11 possible tokens
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/parser/issue-41155.stderr b/src/test/ui/parser/issue-41155.stderr
@@ -1,8 +1,8 @@
-error: expected one of `(`, `async`, `const`, `default`, `extern`, `fn`, `type`, or `unsafe`, found `}`
+error: expected one of `(`, `async`, `const`, `default`, `extern`, `fn`, `type`, `unsafe`, or identifier, found `}`
   --> $DIR/issue-41155.rs:5:1
    |
 LL |     pub
-   |        - expected one of 8 possible tokens
+   |        - expected one of 9 possible tokens
 LL | }
    | ^ unexpected token
 

diff --git a/src/test/ui/parser/issue-58094-missing-right-square-bracket.stderr b/src/test/ui/parser/issue-58094-missing-right-square-bracket.stderr
@@ -7,10 +7,10 @@ LL | #[Ѕ
    |  unclosed delimiter
 
 error: expected item after attributes
-  --> $DIR/issue-58094-missing-right-square-bracket.rs:4:4
+  --> $DIR/issue-58094-missing-right-square-bracket.rs:4:1
    |
 LL | #[Ѕ
-   |    ^
+   | ^^^
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/parser/macro/pub-item-macro.rs b/src/test/ui/parser/macro/pub-item-macro.rs
@@ -1,12 +1,15 @@
 // Issue #14660
 
-macro_rules! priv_x { () => {
-    static x: u32 = 0;
-}}
+macro_rules! priv_x {
+    () => {
+        static x: u32 = 0;
+    };
+}
 
 macro_rules! pub_x { () => {
     pub priv_x!(); //~ ERROR can't qualify macro invocation with `pub`
-    //~^ HELP try adjusting the macro to put `pub` inside the invocation
+    //~^ HELP remove the visibility
+    //~| HELP try adjusting the macro to put `pub` inside the invocation
 }}
 
 mod foo {

diff --git a/src/test/ui/parser/macro/pub-item-macro.stderr b/src/test/ui/parser/macro/pub-item-macro.stderr
@@ -1,8 +1,8 @@
 error: can't qualify macro invocation with `pub`
-  --> $DIR/pub-item-macro.rs:8:5
+  --> $DIR/pub-item-macro.rs:10:5
    |
 LL |     pub priv_x!();
-   |     ^^^
+   |     ^^^ help: remove the visibility
 ...
 LL |     pub_x!();
    |     --------- in this macro invocation
@@ -11,16 +11,16 @@ LL |     pub_x!();
    = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error[E0603]: static `x` is private
-  --> $DIR/pub-item-macro.rs:17:23
+  --> $DIR/pub-item-macro.rs:20:23
    |
 LL |     let y: u32 = foo::x;
    |                       ^ this static is private
    |
 note: the static `x` is defined here
-  --> $DIR/pub-item-macro.rs:4:5
+  --> $DIR/pub-item-macro.rs:5:9
    |
-LL |     static x: u32 = 0;
-   |     ^^^^^^^^^^^^^^^^^^
+LL |         static x: u32 = 0;
+   |         ^^^^^^^^^^^^^^^^^^
 ...
 LL |     pub_x!();
    |     --------- in this macro invocation

diff --git a/src/test/ui/parser/macro/trait-non-item-macros.stderr b/src/test/ui/parser/macro/trait-non-item-macros.stderr
@@ -1,8 +1,8 @@
-error: expected one of `async`, `const`, `crate`, `default`, `extern`, `fn`, `pub`, `type`, or `unsafe`, found `2`
+error: expected one of `async`, `const`, `crate`, `default`, `extern`, `fn`, `pub`, `type`, `unsafe`, or identifier, found `2`
   --> $DIR/trait-non-item-macros.rs:2:19
    |
 LL |     ($a:expr) => ($a)
-   |                   ^^ expected one of 9 possible tokens
+   |                   ^^ expected one of 10 possible tokens
 ...
 LL |     bah!(2);
    |     -------- in this macro invocation

diff --git a/src/test/ui/parser/mismatched-braces/missing-close-brace-in-impl-trait.rs b/src/test/ui/parser/mismatched-braces/missing-close-brace-in-impl-trait.rs
@@ -1,12 +1,14 @@
+fn main() {}
+
 impl T for () { //~ ERROR cannot find trait `T` in this scope
 
 fn foo(&self) {}
+//~^ ERROR missing `fn`, `type`, or `const`
 
-trait T { //~ ERROR expected one of
+trait T {
     fn foo(&self);
 }
 
 pub(crate) struct Bar<T>();
 
-fn main() {}
 //~ ERROR this file contains an unclosed delimiter