isVariableChangedByFunctionCall: Fix FN when constructor argument is const reference

danmar · danmar · commit 5f4b06c0f40a · 2017-09-20T14:03:56.000+02:00
diff --git a/lib/astutils.cpp b/lib/astutils.cpp
@@ -418,10 +418,10 @@ bool isVariableChangedByFunctionCall(const Token *tok, const Settings *settings,
         const ::Scope *typeScope = tok->variable()->typeScope();
         if (typeScope) {
             for (std::list<Function>::const_iterator it = typeScope->functionList.begin(); it != typeScope->functionList.end(); ++it) {
-                if (!it->isConstructor() || it->argCount() != argCount)
+                if (!it->isConstructor() || it->argCount() < argCount)
                     continue;
                 const Variable *arg = it->getArgumentVar(argnr);
-                if (arg && arg->isReference())
+                if (arg && arg->isReference() && !arg->isConst())
                     return true;
             }
             return false;
diff --git a/test/testvalueflow.cpp b/test/testvalueflow.cpp
@@ -1804,14 +1804,25 @@ class TestValueFlow : public TestFixture {
 
         code = "class C {\n"
                "public:\n"
-               "  C(int &i);\n"
+               "  C(int &i);\n" // non-const argument => might be changed
                "};\n"
                "int f() {\n"
                "  int x=1;\n"
                "  C c(x);\n"
                "  return x;\n"
                "}";
         ASSERT_EQUALS(false, testValueOfX(code, 8U, 1));
+
+        code = "class C {\n"
+               "public:\n"
+               "  C(const int &i);\n" // const argument => is not changed
+               "};\n"
+               "int f() {\n"
+               "  int x=1;\n"
+               "  C c(x);\n"
+               "  return x;\n"
+               "}";
+        ASSERT_EQUALS(true, testValueOfX(code, 8U, 1));
     }
 
     void valueFlowForwardLambda() {
