C++: fix code completion: casting inside parentheses

Included unit tests.

Task-number: QTCREATORBUG-8368

Change-Id: I1b04124bc2c9eac050cfb2e6d3a5c1aca5311f4b
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@digia.com>
Reviewed-by: Erik Verbruggen <erik.verbruggen@digia.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/src/libs/cplusplus/ExpressionUnderCursor.cpp b/src/libs/cplusplus/ExpressionUnderCursor.cpp
index b3e0694db0..0c8af020ba 100644
--- a/src/libs/cplusplus/ExpressionUnderCursor.cpp
+++ b/src/libs/cplusplus/ExpressionUnderCursor.cpp
@@ -157,6 +157,8 @@ int ExpressionUnderCursor::startOfExpression_helper(BackwardsScanner &tk, int in
         return index - 1;
     } else if (tk[index - 1].is(T_RPAREN)) {
         int matchingBraceIndex = tk.startOfMatchingBrace(index);
+        if (! matchingBraceIndex)
+            return matchingBraceIndex;
         if (matchingBraceIndex != index) {
             if (tk[matchingBraceIndex - 1].is(T_GREATER)) {
                 int lessIndex = tk.startOfMatchingBrace(matchingBraceIndex);