Improve Fix #6180 (Do not warn about move if it is part of a reassignment of the variable)

Author: zingsheim

lib/valueflow.cpp

@@ -1736,6 +1736,12 @@ static bool isStdMoveOrStdForwarded(Token * tok, ValueFlow::Value::MoveKind * mo
     return true;
 }
 
+static bool isOpenParenthesisMemberFunctionCallOfVarId(const Token * openParenthesisToken, unsigned int varId)
+{
+    return Token::Match(openParenthesisToken->tokAt(-3),"%varid% . %name% (", varId) &&
+           openParenthesisToken->tokAt(-2)->originalName() == emptyString;
+}
+
 static void valueFlowAfterMove(TokenList *tokenlist, SymbolDatabase* symboldatabase, ErrorLogger *errorLogger, const Settings *settings)
 {
     if (!tokenlist->isCPP() || settings->standards.cpp < Standards::CPP11)
@@ -1757,15 +1763,18 @@ static void valueFlowAfterMove(TokenList *tokenlist, SymbolDatabase* symboldatab
             ValueFlow::Value::MoveKind moveKind;
             if (!isStdMoveOrStdForwarded(tok, &moveKind, &varTok))
                 continue;
+            const unsigned int varId = varTok->varId();
             // x is not MOVED after assignment if code is:  x = ... std::move(x) .. ;
             const Token *parent = tok->astParent();
-            while (parent && parent->str() != "=" && parent->str() != "return")
+            while (parent && parent->str() != "=" && parent->str() != "return" &&
+                   !(parent->str() == "(" && isOpenParenthesisMemberFunctionCallOfVarId(parent, varId)))
                 parent = parent->astParent();
-            if (parent && parent->str() == "return") // MOVED in return statement
+            if (parent &&
+                (parent->str() == "return" || // MOVED in return statement
+                 parent->str() == "(")) // MOVED in self assignment, isOpenParenthesisMemberFunctionCallOfVarId == true
                 continue;
-            if (parent && parent->astOperand1()->str() == varTok->str())
+            if (parent && parent->astOperand1()->varId() == varId)
                 continue;
-            const unsigned int varid = varTok->varId();
             const Variable *var = varTok->variable();
             if (!var)
                 continue;
@@ -1778,7 +1787,7 @@ static void valueFlowAfterMove(TokenList *tokenlist, SymbolDatabase* symboldatab
             std::list<ValueFlow::Value> values;
             values.push_back(value);
 
-            valueFlowForward(varTok->next(), endOfVarScope, var, varid, values, false, tokenlist, errorLogger, settings);
+            valueFlowForward(varTok->next(), endOfVarScope, var, varId, values, false, tokenlist, errorLogger, settings);
         }
     }
 }

test/testother.cpp

@@ -179,6 +179,9 @@ class TestOther : public TestFixture {
         TEST_CASE(moveAndAssign1);
         TEST_CASE(moveAndAssign2);
         TEST_CASE(moveAssignMoveAssign);
+        TEST_CASE(moveAndReset1);
+        TEST_CASE(moveAndReset2);
+        TEST_CASE(moveResetMoveReset);
         TEST_CASE(moveAndFunctionParameter);
         TEST_CASE(moveAndFunctionParameterReference);
         TEST_CASE(moveAndFunctionParameterConstReference);
@@ -6189,6 +6192,50 @@ class TestOther : public TestFixture {
                       "[test.cpp:8]: (warning) Access of moved variable a.\n", errout.str());
     }
 
+    void moveAndReset1() {
+        check("A g(A a);\n"
+              "void f() {\n"
+              "    A a;\n"
+              "    a.reset(g(std::move(a)));\n"
+              "    a.reset(g(std::move(a)));\n"
+              "}");
+        ASSERT_EQUALS("", errout.str());
+    }
+
+    void moveAndReset2() {
+        check("A g(A a);\n"
+              "void f() {\n"
+              "    A a;\n"
+              "    A b;\n"
+              "    A c;\n"
+              "    b.reset(g(std::move(a)));\n"
+              "    c.reset(g(std::move(a)));\n"
+              "}");
+        ASSERT_EQUALS("[test.cpp:7]: (warning) Access of moved variable a.\n", errout.str());
+    }
+
+    void moveResetMoveReset() {
+        check("void h(A a);\n"
+              "void f() {"
+              "    A a;\n"
+              "    g(std::move(a));\n"
+              "    h(a);\n"
+              "    a.reset(b);\n"
+              "    h(a);\n"
+              "    g(std::move(a));\n"
+              "    h(a);\n"
+              "    a.reset(b);\n"
+              "    h(a);\n"
+              "}");
+        ASSERT_EQUALS("[test.cpp:4]: (warning) Access of moved variable a.\n"
+                      "[test.cpp:5]: (warning, inconclusive) Access of moved variable a.\n"
+                      "[test.cpp:6]: (warning, inconclusive) Access of moved variable a.\n"
+                      "[test.cpp:7]: (warning, inconclusive) Access of moved variable a.\n"
+                      "[test.cpp:8]: (warning) Access of moved variable a.\n"
+                      "[test.cpp:9]: (warning, inconclusive) Access of moved variable a.\n"
+                      "[test.cpp:10]: (warning, inconclusive) Access of moved variable a.\n", errout.str());
+    }
+
     void moveAndFunctionParameter() {
         check("void g(A a);\n"
               "void f() {\n"