Rollup merge of rust-lang#69708 - estebank:tiny, r=petrochenkov

On mismatched delimiters, only point at empty blocks that are in the same line

We point at empty blocks when we have mismatched braces to detect cases where editors auto insert `}` after writing `{`. Gate this to only the case where the entire span is in the same line so we never point at explicitly empty blocks.

Author: Centril

src/librustc_parse/lexer/tokentrees.rs

@@ -40,6 +40,7 @@ struct TokenTreesReader<'a> {
     /// Used only for error recovery when arriving to EOF with mismatched braces.
     matching_delim_spans: Vec<(token::DelimToken, Span, Span)>,
     last_unclosed_found_span: Option<Span>,
+    /// Collect empty block spans that might have been auto-inserted by editors.
     last_delim_empty_block_spans: FxHashMap<token::DelimToken, Span>,
 }
 
@@ -138,7 +139,11 @@ impl<'a> TokenTreesReader<'a> {
 
                         if tts.is_empty() {
                             let empty_block_span = open_brace_span.to(close_brace_span);
-                            self.last_delim_empty_block_spans.insert(delim, empty_block_span);
+                            if !sm.is_multiline(empty_block_span) {
+                                // Only track if the block is in the form of `{}`, otherwise it is
+                                // likely that it was written on purpose.
+                                self.last_delim_empty_block_spans.insert(delim, empty_block_span);
+                            }
                         }
 
                         if self.open_braces.is_empty() {

src/test/ui/parser/mismatched-delim-brace-empty-block.stderr

@@ -1,14 +1,8 @@
 error: unexpected closing delimiter: `}`
   --> $DIR/mismatched-delim-brace-empty-block.rs:5:1
    |
-LL |   fn main() {
-   |  ___________-
-LL | |
-LL | | }
-   | |_- this block is empty, you might have not meant to close it
-LL |       let _ = ();
-LL |   }
-   |   ^ unexpected closing delimiter
+LL | }
+   | ^ unexpected closing delimiter
 
 error: aborting due to previous error