Fixed #9532 (False positive: Out of bounds access in expression 'v[0]' because 'v' is empty.)

Author: danmar

lib/valueflow.cpp

@@ -5479,7 +5479,7 @@ static void valueFlowContainerForward(Token *tok, nonneg int containerId, ValueF
         }
         if (Token::simpleMatch(tok, ") {") && Token::Match(tok->link()->previous(), "while|for|if (")) {
             const Token *start = tok->next();
-            if (isContainerSizeChanged(containerId, start, start->link()))
+            if (isContainerSizeChanged(containerId, start, start->link()) || isEscapeScope(start, nullptr))
                 break;
             tok = start->link();
             if (Token::simpleMatch(tok, "} else {")) {

test/testother.cpp

@@ -4658,8 +4658,7 @@ class TestOther : public TestFixture {
         ASSERT_EQUALS("", errout.str());
     }
 
-    void duplicateExpression10()
-    {
+    void duplicateExpression10() {
         // #9485
         check("int f() {\n"
               "   const int a = 1;\n"

test/testvalueflow.cpp

@@ -4191,6 +4191,18 @@ class TestValueFlow : public TestFixture {
                "}";
         ASSERT_EQUALS(0U, tokenValues(code, "v . size ( )").size());
 
+        // if
+        code = "bool f(std::vector<int>&) {\n" // #9532
+               "  return false;\n"
+               "}\n"
+               "int g() {\n"
+               "    std::vector<int> v;\n"
+               "    if (f(v) || v.empty())\n"
+               "        return 0;\n"
+               "    return v[0];\n"
+               "}\n";
+        ASSERT_EQUALS(0U, tokenValues(code, "v [ 0 ]").size());
+
         // container size => yields
         code = "void f() {\n"
                "  std::string s = \"abcd\";\n"