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, 1 insertions, 0 deletions

diff --git a/src/plugins/cppeditor/cpphighlighter.h b/src/plugins/cppeditor/cpphighlighter.h
index 358fcb2760..1728ffeb77 100644
--- a/src/plugins/cppeditor/cpphighlighter.h
+++ b/src/plugins/cppeditor/cpphighlighter.h
@@ -29,6 +29,7 @@ private:
     void highlightWord(QStringView word, int position, int length);
     bool highlightRawStringLiteral(QStringView text, const CPlusPlus::Token &tk,
                                    const QString &inheritedSuffix);
+    void highlightStringLiteral(QStringView text, const CPlusPlus::Token &tk);
 
     void highlightDoxygenComment(const QString &text, int position,
                                  int length);