Reduce ammount of errors given unclosed delimiter

When in a file with a non-terminated item, catch the error and consume
the block instead of trying to recover it more granularly in order to
reduce the amount of unrelated errors that would be fixed after adding
the missing closing brace. Also point out the possible location of the
missing closing brace.

1 files changed, 24 insertions, 15 deletions

diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index 6ead1ce811d..5dbe4d95a85 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -27,7 +27,7 @@ use crate::symbol::{kw, sym, Symbol};
 use crate::tokenstream::{self, DelimSpan, TokenTree, TokenStream, TreeAndJoint};
 use crate::ThinVec;
 
-use errors::{Applicability, DiagnosticId, FatalError};
+use errors::{Applicability, DiagnosticBuilder, DiagnosticId, FatalError};
 use rustc_target::spec::abi::{self, Abi};
 use syntax_pos::{Span, BytePos, DUMMY_SP, FileName};
 use log::debug;
@@ -1370,20 +1370,29 @@ impl<'a> Parser<'a> {
     }
 }
 
+crate fn make_unclosed_delims_error(
+    unmatched: UnmatchedBrace,
+    handler: &errors::Handler,
+) -> Option<DiagnosticBuilder<'_>> {
+    // `None` here means an `Eof` was found. We already emit those errors elsewhere, we add them to
+    // `unmatched_braces` only for error recovery in the `Parser`.
+    let found_delim = unmatched.found_delim?;
+    let mut err = handler.struct_span_err(unmatched.found_span, &format!(
+        "incorrect close delimiter: `{}`",
+        pprust::token_kind_to_string(&token::CloseDelim(found_delim)),
+    ));
+    err.span_label(unmatched.found_span, "incorrect close delimiter");
+    if let Some(sp) = unmatched.candidate_span {
+        err.span_label(sp, "close delimiter possibly meant for this");
+    }
+    if let Some(sp) = unmatched.unclosed_span {
+        err.span_label(sp, "un-closed delimiter");
+    }
+    Some(err)
+}
+
 pub fn emit_unclosed_delims(unclosed_delims: &mut Vec<UnmatchedBrace>, handler: &errors::Handler) {
-    for unmatched in unclosed_delims.iter() {
-        let mut err = handler.struct_span_err(unmatched.found_span, &format!(
-            "incorrect close delimiter: `{}`",
-            pprust::token_kind_to_string(&token::CloseDelim(unmatched.found_delim)),
-        ));
-        err.span_label(unmatched.found_span, "incorrect close delimiter");
-        if let Some(sp) = unmatched.candidate_span {
-            err.span_label(sp, "close delimiter possibly meant for this");
-        }
-        if let Some(sp) = unmatched.unclosed_span {
-            err.span_label(sp, "un-closed delimiter");
-        }
-        err.emit();
+    for unmatched in unclosed_delims.drain(..) {
+        make_unclosed_delims_error(unmatched, handler).map(|mut e| e.emit());
     }
-    unclosed_delims.clear();
 }