Fixed #4937 (false positive: Assert calls a function which may have desired side effects)

lib/checkassert.cpp

@@ -69,7 +69,10 @@ void CheckAssert::assertWithSideEffects()
                     if (tok2->type() != Token::eAssignmentOp && tok2->type() != Token::eIncDecOp) continue;
                     const Variable* var = tok2->previous()->variable();
                     if (!var || var->isLocal()) continue;
-
+                    if (var->isArgument() &&
+                        (var->isConst() || (!var->isReference() && !var->isPointer())))
+                        // see ticket #4937. Assigning function arguments not passed by reference is ok.
+                        continue;
                     std::vector<const Token*> returnTokens; // find all return statements
                     for (const Token *rt = scope->classStart; rt != scope->classEnd; rt = rt->next()) {
                         if (!Token::Match(rt, "return %any%")) continue;

lib/symboldatabase.cpp

@@ -1610,6 +1610,7 @@ void SymbolDatabase::printVariable(const Variable *var, const char *indent) cons
     std::cout << indent << "    isMutable: " << (var->isMutable() ? "true" : "false") << std::endl;
     std::cout << indent << "    isStatic: " << (var->isStatic() ? "true" : "false") << std::endl;
     std::cout << indent << "    isExtern: " << (var->isExtern() ? "true" : "false") << std::endl;
+    std::cout << indent << "    isLocal: " << (var->isLocal() ? "true" : "false") << std::endl;
     std::cout << indent << "    isConst: " << (var->isConst() ? "true" : "false") << std::endl;
     std::cout << indent << "    isClass: " << (var->isClass() ? "true" : "false") << std::endl;
     std::cout << indent << "    isArray: " << (var->isArray() ? "true" : "false") << std::endl;

test/testassert.cpp

@@ -89,6 +89,51 @@ private:
             "assert(foo() == 3); \n"
         );
         ASSERT_EQUALS("[test.cpp:6]: (warning) Assert statement calls a function which may have desired side effects: 'foo'.\n", errout.str());
+
+        //  Ticket #4937 "false positive: Assert calls a function which may have desired side effects"
+        check("struct SquarePack {\n"
+              "   static bool isRank1Or8( Square sq ) {\n"
+              "      sq &= 0x38;\n"
+              "      return sq == 0 || sq == 0x38;\n"
+              "    }\n"
+              "};\n"
+              "void foo() {\n"
+              "   assert( !SquarePack::isRank1Or8(push2) );\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+
+        check("struct SquarePack {\n"
+              "   static bool isRank1Or8( Square &sq ) {\n"
+              "      sq &= 0x38;\n"
+              "      return sq == 0 || sq == 0x38;\n"
+              "    }\n"
+              "};\n"
+              "void foo() {\n"
+              "   assert( !SquarePack::isRank1Or8(push2) );\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:8]: (warning) Assert statement calls a function which may have desired side effects: 'isRank1Or8'.\n", errout.str());
+
+        check("struct SquarePack {\n"
+              "   static bool isRank1Or8( Square *sq ) {\n"
+              "      *sq &= 0x38;\n"
+              "      return *sq == 0 || *sq == 0x38;\n"
+              "    }\n"
+              "};\n"
+              "void foo() {\n"
+              "   assert( !SquarePack::isRank1Or8(push2) );\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:8]: (warning) Assert statement calls a function which may have desired side effects: 'isRank1Or8'.\n", errout.str());
+
+        check("struct SquarePack {\n"
+              "   static bool isRank1Or8( Square *sq ) {\n"
+              "      sq &= 0x38;\n"
+              "      return sq == 0 || sq == 0x38;\n"
+              "    }\n"
+              "};\n"
+              "void foo() {\n"
+              "   assert( !SquarePack::isRank1Or8(push2) );\n"
+              "}\n");
+        TODO_ASSERT_EQUALS("", "[test.cpp:8]: (warning) Assert statement calls a function which may have desired side effects: 'isRank1Or8'.\n", errout.str());
     }
 
     void assignmentInAssert() {