Tweak unclosed delimiter parser error

src/libsyntax/parse/lexer/mod.rs

@@ -67,6 +67,7 @@ pub struct StringReader<'a> {
     span_src_raw: Span,
     open_braces: Vec<(token::DelimToken, Span)>,
     crate override_span: Option<Span>,
+    last_unclosed_found_span: Option<Span>,
 }
 
 impl<'a> StringReader<'a> {
@@ -195,6 +196,7 @@ impl<'a> StringReader<'a> {
             span_src_raw: syntax_pos::DUMMY_SP,
             open_braces: Vec::new(),
             override_span,
+            last_unclosed_found_span: None,
         }
     }
 

src/libsyntax/parse/lexer/tokentrees.rs

@@ -77,16 +77,23 @@ impl<'a> StringReader<'a> {
                     // Incorrect delimiter.
                     token::CloseDelim(other) => {
                         let token_str = token_to_string(&self.token);
-                        let msg = format!("incorrect close delimiter: `{}`", token_str);
-                        let mut err = self.sess.span_diagnostic.struct_span_err(self.span, &msg);
-                        // This is a conservative error: only report the last unclosed delimiter.
-                        // The previous unclosed delimiters could actually be closed! The parser
-                        // just hasn't gotten to them yet.
-                        if let Some(&(_, sp)) = self.open_braces.last() {
-                            err.span_note(sp, "unclosed delimiter");
-                        };
-                        err.emit();
-
+                        if self.last_unclosed_found_span != Some(self.span) {
+                            // do not complain about the same unclosed delimiter multiple times
+                            self.last_unclosed_found_span = Some(self.span);
+                            let msg = format!("incorrect close delimiter: `{}`", token_str);
+                            let mut err = self.sess.span_diagnostic.struct_span_err(
+                                self.span,
+                                &msg,
+                            );
+                            err.span_label(self.span, "incorrect close delimiter");
+                            // This is a conservative error: only report the last unclosed
+                            // delimiter. The previous unclosed delimiters could actually be
+                            // closed! The parser just hasn't gotten to them yet.
+                            if let Some(&(_, sp)) = self.open_braces.last() {
+                                err.span_label(sp, "unclosed delimiter");
+                            };
+                            err.emit();
+                        }
                         self.open_braces.pop().unwrap();
 
                         // If the incorrect delimiter matches an earlier opening
@@ -118,7 +125,8 @@ impl<'a> StringReader<'a> {
                 // matching opening delimiter).
                 let token_str = token_to_string(&self.token);
                 let msg = format!("unexpected close delimiter: `{}`", token_str);
-                let err = self.sess.span_diagnostic.struct_span_err(self.span, &msg);
+                let mut err = self.sess.span_diagnostic.struct_span_err(self.span, &msg);
+                err.span_label(self.span, "unexpected close delimiter");
                 Err(err)
             },
             _ => {

src/test/ui-fulldeps/invalid-punct-ident-4.stderr

@@ -2,7 +2,7 @@ error: unexpected close delimiter: `)`
   --> $DIR/invalid-punct-ident-4.rs:16:1
    |
 LL | lexer_failure!(); //~ ERROR proc macro panicked
-   | ^^^^^^^^^^^^^^^^^
+   | ^^^^^^^^^^^^^^^^^ unexpected close delimiter
 
 error: proc macro panicked
   --> $DIR/invalid-punct-ident-4.rs:16:1

src/test/parse-fail/issue-10636-1.rs → src/test/ui/issue-10636-1.rs

@@ -12,4 +12,8 @@
 
 struct Obj { //~ NOTE: unclosed delimiter
     member: usize
-) //~ ERROR: incorrect close delimiter
+)
+//~^ ERROR incorrect close delimiter
+//~| NOTE incorrect close delimiter
+
+fn main() {}

src/test/ui/issue-10636-1.stderr

@@ -0,0 +1,11 @@
+error: incorrect close delimiter: `)`
+  --> $DIR/issue-10636-1.rs:15:1
+   |
+LL | struct Obj { //~ NOTE: unclosed delimiter
+   |            - unclosed delimiter
+LL |     member: usize
+LL | )
+   | ^ incorrect close delimiter
+
+error: aborting due to previous error
+

src/test/ui/parser-recovery-2.stderr

@@ -1,14 +1,11 @@
 error: incorrect close delimiter: `)`
   --> $DIR/parser-recovery-2.rs:18:5
    |
-LL |     ) //~ ERROR incorrect close delimiter: `)`
-   |     ^
-   |
-note: unclosed delimiter
-  --> $DIR/parser-recovery-2.rs:16:14
-   |
 LL |     fn bar() {
-   |              ^
+   |              - unclosed delimiter
+LL |         let x = foo(); //~ ERROR cannot find function `foo` in this scope
+LL |     ) //~ ERROR incorrect close delimiter: `)`
+   |     ^ incorrect close delimiter
 
 error: unexpected token: `;`
   --> $DIR/parser-recovery-2.rs:22:15

src/test/ui/resolve/token-error-correct-2.stderr

@@ -1,14 +1,11 @@
 error: incorrect close delimiter: `)`
   --> $DIR/token-error-correct-2.rs:16:5
    |
-LL |     ) //~ ERROR: incorrect close delimiter: `)`
-   |     ^
-   |
-note: unclosed delimiter
-  --> $DIR/token-error-correct-2.rs:14:12
-   |
 LL |     if foo {
-   |            ^
+   |            - unclosed delimiter
+LL |     //~^ ERROR: cannot find value `foo`
+LL |     ) //~ ERROR: incorrect close delimiter: `)`
+   |     ^ incorrect close delimiter
 
 error[E0425]: cannot find value `foo` in this scope
   --> $DIR/token-error-correct-2.rs:14:8

src/test/ui/resolve/token-error-correct-3.stderr

@@ -1,14 +1,11 @@
 error: incorrect close delimiter: `}`
   --> $DIR/token-error-correct-3.rs:30:9
    |
-LL |         } else { //~ ERROR: incorrect close delimiter: `}`
-   |         ^
-   |
-note: unclosed delimiter
-  --> $DIR/token-error-correct-3.rs:24:21
-   |
 LL |             callback(path.as_ref(); //~ ERROR expected one of
-   |                     ^
+   |                     - unclosed delimiter
+...
+LL |         } else { //~ ERROR: incorrect close delimiter: `}`
+   |         ^ incorrect close delimiter
 
 error: expected one of `)`, `,`, `.`, `?`, or an operator, found `;`
   --> $DIR/token-error-correct-3.rs:24:35

src/test/ui/resolve/token-error-correct.rs

@@ -15,4 +15,3 @@ fn main() {
     //~^ ERROR: expected expression, found `;`
 }
 //~^ ERROR: incorrect close delimiter: `}`
-//~| ERROR: incorrect close delimiter: `}`

src/test/ui/resolve/token-error-correct.stderr

@@ -1,32 +1,17 @@
 error: incorrect close delimiter: `}`
   --> $DIR/token-error-correct.rs:16:1
    |
-LL | }
-   | ^
-   |
-note: unclosed delimiter
-  --> $DIR/token-error-correct.rs:14:12
-   |
 LL |     foo(bar(;
-   |            ^
-
-error: incorrect close delimiter: `}`
-  --> $DIR/token-error-correct.rs:16:1
-   |
+   |            - unclosed delimiter
+LL |     //~^ ERROR: expected expression, found `;`
 LL | }
-   | ^
-   |
-note: unclosed delimiter
-  --> $DIR/token-error-correct.rs:14:8
-   |
-LL |     foo(bar(;
-   |        ^
+   | ^ incorrect close delimiter
 
 error: expected expression, found `;`
   --> $DIR/token-error-correct.rs:14:13
    |
 LL |     foo(bar(;
    |             ^ expected expression
 
-error: aborting due to 3 previous errors
+error: aborting due to 2 previous errors
 

src/test/ui/token/issue-10636-2.stderr

@@ -1,14 +1,11 @@
 error: incorrect close delimiter: `}`
   --> $DIR/issue-10636-2.rs:18:1
    |
-LL | } //~ ERROR: incorrect close delimiter
-   | ^
-   |
-note: unclosed delimiter
-  --> $DIR/issue-10636-2.rs:15:15
-   |
 LL |     option.map(|some| 42;
-   |               ^
+   |               - unclosed delimiter
+...
+LL | } //~ ERROR: incorrect close delimiter
+   | ^ incorrect close delimiter
 
 error: expected one of `)`, `,`, `.`, `?`, or an operator, found `;`
   --> $DIR/issue-10636-2.rs:15:25