Bail when encountering a second unexpected token in the same span

Author: estebank

src/libsyntax/parse/parser.rs

@@ -46,7 +46,7 @@ use crate::ThinVec;
 use crate::tokenstream::{self, DelimSpan, TokenTree, TokenStream, TreeAndJoint};
 use crate::symbol::{Symbol, keywords};
 
-use errors::{Applicability, DiagnosticBuilder, DiagnosticId};
+use errors::{Applicability, DiagnosticBuilder, DiagnosticId, FatalError};
 use rustc_target::spec::abi::{self, Abi};
 use syntax_pos::{Span, MultiSpan, BytePos, FileName};
 use log::{debug, trace};
@@ -256,6 +256,7 @@ pub struct Parser<'a> {
     /// it gets removed from here. Every entry left at the end gets emitted as an independent
     /// error.
     crate unclosed_delims: Vec<UnmatchedBrace>,
+    last_unexpected_token_span: Option<Span>,
 }
 
 
@@ -582,6 +583,7 @@ impl<'a> Parser<'a> {
             unmatched_angle_bracket_count: 0,
             max_angle_bracket_count: 0,
             unclosed_delims: Vec::new(),
+            last_unexpected_token_span: None,
         };
 
         let tok = parser.next_tok();
@@ -775,6 +777,8 @@ impl<'a> Parser<'a> {
         } else if inedible.contains(&self.token) {
             // leave it in the input
             Ok(false)
+        } else if self.last_unexpected_token_span == Some(self.span) {
+            FatalError.raise();
         } else {
             let mut expected = edible.iter()
                 .map(|x| TokenType::Token(x.clone()))
@@ -802,6 +806,7 @@ impl<'a> Parser<'a> {
                  (self.sess.source_map().next_point(self.prev_span),
                   format!("expected {} here", expect)))
             };
+            self.last_unexpected_token_span = Some(self.span);
             let mut err = self.fatal(&msg_exp);
             if self.token.is_ident_named("and") {
                 err.span_suggestion_short(
@@ -6332,10 +6337,11 @@ impl<'a> Parser<'a> {
                     &token::CloseDelim(token::Paren), sep, parse_arg_fn)?;
                 fn_inputs.append(&mut input);
                 (fn_inputs, recovered)
-            } else if let Err(err) = self.expect_one_of(&[], &[]) {
-                return Err(err);
             } else {
-                (vec![self_arg], true)
+                match self.expect_one_of(&[], &[]) {
+                    Err(err) => return Err(err),
+                    Ok(recovered) => (vec![self_arg], recovered),
+                }
             }
         } else {
             self.parse_seq_to_before_end(&token::CloseDelim(token::Paren), sep, parse_arg_fn)?

src/test/ui/issues/issue-58856-1.rs

@@ -1,9 +1,8 @@
+struct A;
+
 impl A {
-//~^ ERROR cannot find type `A` in this scope
-    fn b(self>
+    fn b(self> {}
     //~^ ERROR expected one of `)`, `,`, or `:`, found `>`
-    //~| ERROR expected one of `->`, `where`, or `{`, found `>`
-    //~| ERROR expected one of `->`, `async`, `const`, `crate`, `default`, `existential`,
 }
 
 fn main() {}

src/test/ui/issues/issue-58856-1.stderr

@@ -1,30 +1,11 @@
 error: expected one of `)`, `,`, or `:`, found `>`
-  --> $DIR/issue-58856-1.rs:3:14
+  --> $DIR/issue-58856-1.rs:4:14
    |
-LL |     fn b(self>
+LL |     fn b(self> {}
    |         -    ^
    |         |    |
    |         |    help: `)` may belong here
    |         unclosed delimiter
 
-error: expected one of `->`, `where`, or `{`, found `>`
-  --> $DIR/issue-58856-1.rs:3:14
-   |
-LL |     fn b(self>
-   |              ^ expected one of `->`, `where`, or `{` here
-
-error: expected one of `->`, `async`, `const`, `crate`, `default`, `existential`, `extern`, `fn`, `pub`, `type`, `unsafe`, `where`, or `}`, found `>`
-  --> $DIR/issue-58856-1.rs:3:14
-   |
-LL |     fn b(self>
-   |              ^ expected one of 13 possible tokens here
-
-error[E0412]: cannot find type `A` in this scope
-  --> $DIR/issue-58856-1.rs:1:6
-   |
-LL | impl A {
-   |      ^ not found in this scope
-
-error: aborting due to 4 previous errors
+error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0412`.

src/test/ui/issues/issue-58856-2.rs

@@ -1,11 +1,12 @@
+struct Empty;
+
 trait Howness {}
+
 impl Howness for () {
     fn how_are_you(&self -> Empty {
     //~^ ERROR expected one of `)` or `,`, found `->`
     //~| ERROR method `how_are_you` is not a member of trait `Howness`
-    //~| ERROR cannot find type `Empty` in this scope
         Empty
-        //~^ ERROR cannot find value `Empty` in this scope
     }
 }
 //~^ ERROR expected one of `async`, `const`, `crate`, `default`, `existential`, `extern`, `fn`,

src/test/ui/issues/issue-58856-2.stderr

@@ -1,5 +1,5 @@
 error: expected one of `)` or `,`, found `->`
-  --> $DIR/issue-58856-2.rs:3:26
+  --> $DIR/issue-58856-2.rs:6:26
    |
 LL |     fn how_are_you(&self -> Empty {
    |                   -     -^^
@@ -8,48 +8,23 @@ LL |     fn how_are_you(&self -> Empty {
    |                   unclosed delimiter
 
 error: expected one of `async`, `const`, `crate`, `default`, `existential`, `extern`, `fn`, `pub`, `type`, `unsafe`, or `}`, found `)`
-  --> $DIR/issue-58856-2.rs:10:1
+  --> $DIR/issue-58856-2.rs:11:1
    |
 LL |     }
    |      - expected one of 11 possible tokens here
 LL | }
    | ^ unexpected token
 
 error[E0407]: method `how_are_you` is not a member of trait `Howness`
-  --> $DIR/issue-58856-2.rs:3:5
+  --> $DIR/issue-58856-2.rs:6:5
    |
 LL | /     fn how_are_you(&self -> Empty {
 LL | |     //~^ ERROR expected one of `)` or `,`, found `->`
 LL | |     //~| ERROR method `how_are_you` is not a member of trait `Howness`
-LL | |     //~| ERROR cannot find type `Empty` in this scope
 LL | |         Empty
-LL | |         //~^ ERROR cannot find value `Empty` in this scope
 LL | |     }
    | |_____^ not a member of trait `Howness`
 
-error[E0412]: cannot find type `Empty` in this scope
-  --> $DIR/issue-58856-2.rs:3:29
-   |
-LL |     fn how_are_you(&self -> Empty {
-   |                             ^^^^^ not found in this scope
-help: possible candidates are found in other modules, you can import them into scope
-   |
-LL | use std::io::Empty;
-   |
-LL | use std::iter::Empty;
-   |
-
-error[E0425]: cannot find value `Empty` in this scope
-  --> $DIR/issue-58856-2.rs:7:9
-   |
-LL |         Empty
-   |         ^^^^^ not found in this scope
-help: possible candidate is found in another module, you can import it into scope
-   |
-LL | use std::sync::mpsc::TryRecvError::Empty;
-   |
-
-error: aborting due to 5 previous errors
+error: aborting due to 3 previous errors
 
-Some errors occurred: E0407, E0412, E0425.
-For more information about an error, try `rustc --explain E0407`.
+For more information about this error, try `rustc --explain E0407`.

src/test/ui/parser/recover-enum2.rs

@@ -25,9 +25,6 @@ fn main() {
         // fail again
         enum Test4 {
             Nope(i32 {}) //~ ERROR: found `{`
-                         //~^ ERROR: found `{`
         }
     }
-    // still recover later
-    let bad_syntax = _; //~ ERROR: expected expression, found reserved identifier `_`
 }

src/test/ui/parser/recover-enum2.stderr

@@ -10,17 +10,5 @@ error: expected one of `!`, `(`, `)`, `+`, `,`, `::`, or `<`, found `{`
 LL |             Nope(i32 {}) //~ ERROR: found `{`
    |                      ^ expected one of 7 possible tokens here
 
-error: expected one of `!`, `&&`, `&`, `(`, `)`, `*`, `+`, `,`, `...`, `::`, `<`, `?`, `[`, `_`, `crate`, `dyn`, `extern`, `fn`, `for`, `impl`, `pub`, `unsafe`, `}`, or lifetime, found `{`
-  --> $DIR/recover-enum2.rs:27:22
-   |
-LL |             Nope(i32 {}) //~ ERROR: found `{`
-   |                      ^ expected one of 24 possible tokens here
-
-error: expected expression, found reserved identifier `_`
-  --> $DIR/recover-enum2.rs:32:22
-   |
-LL |     let bad_syntax = _; //~ ERROR: expected expression, found reserved identifier `_`
-   |                      ^ expected expression
-
-error: aborting due to 4 previous errors
+error: aborting due to 2 previous errors