Fix #11404 FP knownConditionTrueFalse with iterator (#4619)

* Fix wrong value set in valueFlowSameExpressions()

* Fix  #11404 FP knownConditionTrueFalse with iterator

Author: chrchr-github

lib/astutils.cpp

@@ -2735,8 +2735,13 @@ bool isExpressionChanged(const Token* expr, const Token* start, const Token* end
 
         if (tok->exprId() > 0) {
             for (const Token* tok2 = start; tok2 != end; tok2 = tok2->next()) {
-                if (isExpressionChangedAt(
-                        tok, tok2, tok->valueType() ? tok->valueType()->pointer : 0, global, settings, cpp, depth))
+                int indirect = 0;
+                if (const ValueType* vt = tok->valueType()) {
+                    indirect = vt->pointer;
+                    if (vt->type == ValueType::ITERATOR)
+                        ++indirect;
+                }
+                if (isExpressionChangedAt(tok, tok2, indirect, global, settings, cpp, depth))
                     return true;
             }
         }

lib/valueflow.cpp

@@ -2440,8 +2440,11 @@ struct ValueFlowAnalyzer : Analyzer {
             // TODO: Check if modified in the lambda function
             return Action::Invalid;
         int indirect = 0;
-        if (tok->valueType())
-            indirect = tok->valueType()->pointer;
+        if (const ValueType* vt = tok->valueType()) {
+            indirect = vt->pointer;
+            if (vt->type == ValueType::ITERATOR)
+                ++indirect;
+        }
         if (isVariableChanged(tok, indirect, getSettings(), isCPP()))
             return Action::Invalid;
         return Action::None;

test/testcondition.cpp

@@ -4628,6 +4628,18 @@ class TestCondition : public TestFixture {
               "    if (!std::isalnum(c)) {}\n"
               "}\n");
         ASSERT_EQUALS("", errout.str());
+
+        check("struct S {\n" // #11404
+              "    int f() const;\n"
+              "    void g();\n"
+              "};\n"
+              "void h(std::vector<S*>::iterator it) {\n"
+              "    auto i = (*it)->f();\n"
+              "    (*it)->g();\n"
+              "    auto j = (*it)->f();\n"
+              "    if (i == j) {}\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
     }
 
     void alwaysTrueInfer() {