Properly escape quotes when suggesting switching between char/string literals

diff --git a/compiler/rustc_infer/src/infer/error_reporting/mod.rs b/compiler/rustc_infer/src/infer/error_reporting/mod.rs
index ddeeaa9618e606524033bebf51bf3da7a14288a1..88ffbe0b539acc1f994d538095f320b0f6d2a123 100644 (file)
--- a/compiler/rustc_infer/src/infer/error_reporting/mod.rs
+++ b/compiler/rustc_infer/src/infer/error_reporting/mod.rs
@@ -2272,6 +2272,25 @@ pub fn report_and_explain_type_error(
                 struct_span_err!(self.tcx.sess, span, E0580, "{}", failure_str)
             }
             FailureCode::Error0308(failure_str) => {
+                fn escape_literal(s: &str) -> String {
+                    let mut escaped = String::with_capacity(s.len());
+                    let mut chrs = s.chars().peekable();
+                    while let Some(first) = chrs.next() {
+                        match (first, chrs.peek()) {
+                            ('\\', Some(&delim @ '"') | Some(&delim @ '\'')) => {
+                                escaped.push('\\');
+                                escaped.push(delim);
+                                chrs.next();
+                            }
+                            ('"' | '\'', _) => {
+                                escaped.push('\\');
+                                escaped.push(first)
+                            }
+                            (c, _) => escaped.push(c),
+                        };
+                    }
+                    escaped
+                }
                 let mut err = struct_span_err!(self.tcx.sess, span, E0308, "{}", failure_str);
                 if let Some((expected, found)) = trace.values.ty() {
                     match (expected.kind(), found.kind()) {
@@ -2293,7 +2312,7 @@ pub fn report_and_explain_type_error(
                                 err.span_suggestion(
                                     span,
                                     "if you meant to write a `char` literal, use single quotes",
-                                    format!("'{}'", code),
+                                    format!("'{}'", escape_literal(code)),
                                     Applicability::MachineApplicable,
                                 );
                             }
@@ -2308,7 +2327,7 @@ pub fn report_and_explain_type_error(
                                     err.span_suggestion(
                                         span,
                                         "if you meant to write a `str` literal, use double quotes",
-                                        format!("\"{}\"", code),
+                                        format!("\"{}\"", escape_literal(code)),
                                         Applicability::MachineApplicable,
                                     );
                                 }

diff --git a/compiler/rustc_parse/src/lexer/unescape_error_reporting.rs b/compiler/rustc_parse/src/lexer/unescape_error_reporting.rs
index 77c4fadab45eacc9f61d5fd4cb4d361cedc62666..f075de714267688eb0711fe0e631f14cb9c485d3 100644 (file)
--- a/compiler/rustc_parse/src/lexer/unescape_error_reporting.rs
+++ b/compiler/rustc_parse/src/lexer/unescape_error_reporting.rs
@@ -113,11 +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,
                 );
             }