Partial fix for #14524 FN memleak with C++ cast (danmar#8249)

Author: chrchr-github

lib/checkmemoryleak.cpp

@@ -56,13 +56,16 @@ CheckMemoryLeak::AllocType CheckMemoryLeak::getAllocationType(const Token *tok2,
 {
     // What we may have...
     //     * var = (char *)malloc(10);
+    //     * var = static_cast<char *>(malloc(10));
     //     * var = new char[10];
     //     * var = strdup("hello");
     //     * var = strndup("hello", 3);
     if (tok2 && tok2->str() == "(") {
         tok2 = tok2->link();
         tok2 = tok2 ? tok2->next() : nullptr;
     }
+    if (tok2 && tok2->isCpp() && tok2->isKeyword() && endsWith(tok2->str(), "_cast"))
+        tok2 = tok2->astParent()->next();
     if (!tok2)
         return No;
     if (tok2->str() == "::")

test/testmemleak.cpp

@@ -1674,6 +1674,7 @@ class TestMemleakStructMember : public TestFixture {
         TEST_CASE(assign3);
         TEST_CASE(assign4); // #11019
         TEST_CASE(assign5);
+        TEST_CASE(assign6);
 
         // Failed allocation
         TEST_CASE(failedAllocation);
@@ -1955,6 +1956,15 @@ class TestMemleakStructMember : public TestFixture {
         ASSERT_EQUALS("", errout_str());
     }
 
+    void assign6() {
+        check("struct S { S* p; };\n" // #14524
+              "void f() {\n"
+              "    S s;\n"
+              "    s.p = static_cast<S*>(malloc(sizeof(S)));\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:5:1]: (error) Memory leak: s.p [memleak]\n", errout_str());
+    }
+
     void failedAllocation() {
         check("static struct ABC * foo()\n"
               "{\n"