Fix #12288 FP: uninitvar (in place new) (danmar#5859)

Author: chrchr-github

lib/astutils.cpp

@@ -2418,6 +2418,9 @@ bool isVariableChangedByFunctionCall(const Token *tok, int indirect, const Setti
     if (deref && indirect > 0)
         indirect--;
 
+    if (indirect == 1 && tok->isCpp() && tok->tokAt(-1) && Token::simpleMatch(tok->tokAt(-2), "new (")) // placement new TODO: fix AST
+        return true;
+
     int argnr;
     tok = getTokenArgumentFunction(tok, argnr);
     if (!tok)

test/testuninitvar.cpp

@@ -6373,6 +6373,12 @@ class TestUninitVar : public TestFixture {
                         "    g(buf);\n"
                         "}\n");
         ASSERT_EQUALS("[test.cpp:4]: (error) Uninitialized variable: buf\n", errout.str());
+
+        valueFlowUninit("void f() {\n" // #12288
+                        "    char buf[100];\n"
+                        "    char* p = new (buf) char[100];\n"
+                        "}\n");
+        ASSERT_EQUALS("", errout.str());
     }
 
     void valueFlowUninitBreak() { // Do not show duplicate warnings about the same uninitialized value