Fix #14582 FP uninitvar (array accessed via cast) (#8329)

Author: chrchr-github

lib/astutils.cpp

@@ -2636,7 +2636,8 @@ bool isVariableChanged(const Token *tok, int indirect, const Settings &settings,
     while ((tok2->astParent() && tok2->astParent()->isUnaryOp("*")) ||
            (Token::simpleMatch(tok2->astParent(), ".") && !Token::Match(tok2->astParent()->astParent(), "[(,]")) ||
            (tok2->astParent() && tok2->astParent()->isUnaryOp("&") && Token::simpleMatch(tok2->astParent()->astParent(), ".") && tok2->astParent()->astParent()->originalName()=="->") ||
-           (Token::simpleMatch(tok2->astParent(), "[") && tok2 == tok2->astParent()->astOperand1())) {
+           (Token::simpleMatch(tok2->astParent(), "[") && tok2 == tok2->astParent()->astOperand1()) ||
+           (Token::simpleMatch(tok2->astParent(), "(") && tok2->astParent()->isCast())) {
         if (tok2->astParent() && (tok2->astParent()->isUnaryOp("*") || (astIsLHS(tok2) && tok2->astParent()->originalName() == "->" && !hasOverloadedMemberAccess(tok2))))
             derefs++;
         if (derefs > indirect)

test/testuninitvar.cpp

@@ -6696,6 +6696,18 @@ class TestUninitVar : public TestFixture {
                         "    return [&]() { return j; }();\n"
                         "}\n");
         ASSERT_EQUALS("[test.cpp:17:27]: (error) Uninitialized variable: j [uninitvar]\n", errout_str());
+
+        valueFlowUninit("int f() {\n" // #14582
+                        "    int a[1];\n"
+                        "    static_cast<int*>(a)[0] = 0;\n"
+                        "    return a[0];\n"
+                        "}\n"
+                        "int g() {\n"
+                        "    int a[1];\n"
+                        "    ((int*)a)[0] = 0;\n"
+                        "    return a[0];\n"
+                        "}\n");
+        ASSERT_EQUALS("", errout_str());
     }
 
     void valueFlowUninitBreak() { // Do not show duplicate warnings about the same uninitialized value