Properly escape quotes when suggesting switching between char/string literals

[rust.git] / compiler / rustc_parse / src / lexer / unescape_error_reporting.rs

diff --git a/compiler/rustc_parse/src/lexer/unescape_error_reporting.rs b/compiler/rustc_parse/src/lexer/unescape_error_reporting.rs
index 273827864f1a405295e2f7f0499d605c82f290f0..f075de714267688eb0711fe0e631f14cb9c485d3 100644 (file)
--- a/compiler/rustc_parse/src/lexer/unescape_error_reporting.rs
+++ b/compiler/rustc_parse/src/lexer/unescape_error_reporting.rs
@@ -20,13 +20,9 @@ pub(crate) fn emit_unescape_error(
     range: Range<usize>,
     error: EscapeError,
 ) {
-    tracing::debug!(
+    debug!(
         "emit_unescape_error: {:?}, {:?}, {:?}, {:?}, {:?}",
-        lit,
-        span_with_quotes,
-        mode,
-        range,
-        error
+        lit, span_with_quotes, mode, range, error
     );
     let last_char = || {
         let c = lit[range.clone()].chars().rev().next().unwrap();
@@ -117,11 +113,26 @@ pub(crate) fn emit_unescape_error(
                 } else {
                     ("", "if you meant to write a `str` literal, use double quotes")
                 };
-
+                let mut escaped = String::with_capacity(lit.len());
+                let mut chrs = lit.chars().peekable();
+                while let Some(first) = chrs.next() {
+                    match (first, chrs.peek()) {
+                        ('\\', Some('"')) => {
+                            escaped.push('\\');
+                            escaped.push('"');
+                            chrs.next();
+                        }
+                        ('"', _) => {
+                            escaped.push('\\');
+                            escaped.push('"')
+                        }
+                        (c, _) => escaped.push(c),
+                    };
+                }
                 handler.span_suggestion(
                     span_with_quotes,
                     msg,
-                    format!("{}\"{}\"", prefix, lit),
+                    format!("{prefix}\"{escaped}\""),
                     Applicability::MachineApplicable,
                 );
             }