Clang: Fix move assignment in ClangString

Don't move if you assign to yourself.

Change-Id: I33977fe34cc89849337c17c1ff418ff48d68e708
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@theqtcompany.com>

src/tools/clangbackend/ipcsource/clangstring.cpp

@@ -49,20 +49,23 @@ bool ClangString::isNull() const
     return cxString.data == nullptr;
 }
 
-ClangString &ClangString::operator=(ClangString &&clangString)
+ClangString &ClangString::operator=(ClangString &&other)
 {
-    cxString = std::move(clangString.cxString);
-    clangString.cxString.data = nullptr;
-    clangString.cxString.private_flags = 0;
+    if (this != &other) {
+        clang_disposeString(cxString);
+        cxString = std::move(other.cxString);
+        other.cxString.data = nullptr;
+        other.cxString.private_flags = 0;
+    }
 
     return *this;
 }
 
-ClangString::ClangString(ClangString &&clangString)
-    : cxString(std::move(clangString.cxString))
+ClangString::ClangString(ClangString &&other)
+    : cxString(std::move(other.cxString))
 {
-    clangString.cxString.data = nullptr;
-    clangString.cxString.private_flags = 0;
+    other.cxString.data = nullptr;
+    other.cxString.private_flags = 0;
 }
 
 ClangString::operator Utf8String() const

src/tools/clangbackend/ipcsource/clangstring.h

@@ -43,11 +43,11 @@ public:
     ClangString(CXString cxString);
     ~ClangString();
 
-    ClangString(const ClangString &clangString) = delete;
-    const ClangString &operator=(const ClangString &clangString) = delete;
+    ClangString(const ClangString &) = delete;
+    const ClangString &operator=(const ClangString &) = delete;
 
-    ClangString(ClangString &&clangString);
-    ClangString &operator=(ClangString &&clangString);
+    ClangString(ClangString &&other);
+    ClangString &operator=(ClangString &&other);
 
     operator Utf8String() const;