[clang] bad error message on incorrect string literal #18079 (PR #81670)

[Jon Roelofs via cfe-commits]

================
@@ -2270,10 +2270,12 @@ bool Lexer::LexRawStringLiteral(Token &Result, const char *CurPtr,
       const char *PrefixEnd = &CurPtr[PrefixLen];
       if (PrefixLen == 16) {
         Diag(PrefixEnd, diag::err_raw_delim_too_long);
-      } else {
+      } else if (*PrefixEnd != '\n') {
         Diag(PrefixEnd, diag::err_invalid_char_raw_delim)
           << StringRef(PrefixEnd, 1);
-      }
+      } else {
+        Diag(PrefixEnd, diag::err_invalid_nexline_raw_delim);
+	}
----------------
jroelofs wrote:

```suggestion
        Diag(PrefixEnd, diag::err_invalid_newline_raw_delim);
      }
```

https://github.com/llvm/llvm-project/pull/81670