CppEditor: More special rendering for string literals

Display prefixes and suffixes different from the actual string, like we
already did for raw string literals.
This uncovered some minor bugs in both lexer and highlighter:
  - Wrong length for a setFormat() call in highlightRawStringLiteral()
  - Missing check for user-defined literal in raw string literals
  - Missing check for user-defined literal in multi-line strings

Fixes: QTCREATORBUG-28869
Change-Id: I018717c50ddc1d09c609556161c85dfb0cc29fab
Reviewed-by: David Schulz <david.schulz@qt.io>

1 files changed, 6 insertions, 1 deletions

diff --git a/src/libs/3rdparty/cplusplus/Lexer.cpp b/src/libs/3rdparty/cplusplus/Lexer.cpp
index e2f1b4e0e6..fc1b72cb7d 100644
--- a/src/libs/3rdparty/cplusplus/Lexer.cpp
+++ b/src/libs/3rdparty/cplusplus/Lexer.cpp
@@ -217,14 +217,17 @@ void Lexer::scan_helper(Token *tok)
         tok->f.kind = s._tokenKind;
         const bool found = _expectedRawStringSuffix.isEmpty()
                 ? scanUntilRawStringLiteralEndSimple() : scanUntilRawStringLiteralEndPrecise();
-        if (found)
+        if (found) {
+            scanOptionalUserDefinedLiteral(tok);
             _state = 0;
+        }
         return;
     } else { // non-raw strings
         tok->f.joined = true;
         tok->f.kind = s._tokenKind;
         _state = 0;
         scanUntilQuote(tok, '"');
+        scanOptionalUserDefinedLiteral(tok);
         return;
     }
 
@@ -829,6 +832,8 @@ void Lexer::scanRawStringLiteral(Token *tok, unsigned char hint)
         _expectedRawStringSuffix.prepend(')');
         _expectedRawStringSuffix.append('"');
     }
+    if (closed)
+        scanOptionalUserDefinedLiteral(tok);
 }
 
 bool Lexer::scanUntilRawStringLiteralEndPrecise()