Fix #15060 Nullptr dereference in exprDependsOnThis() (#8894)

Co-authored-by: chrchr-github <noreply@github.com>

Author: chrchr-github

lib/tokenize.cpp

@@ -9166,9 +9166,19 @@ void Tokenizer::findGarbageCode() const
             syntaxError(tok);
         if (Token::Match(tok, "==|!=|<=|>= %comp%") && tok->strAt(-1) != "operator")
             syntaxError(tok, tok->str() + " " + tok->strAt(1));
-        if (Token::simpleMatch(tok, "::") && (!Token::Match(tok->next(), "%name%|*|~") ||
-                                              (tok->next()->isKeyword() && !Token::Match(tok->next(), "new|delete|operator"))))
-            syntaxError(tok);
+        if (Token::simpleMatch(tok, "::")) {
+            if (!Token::Match(tok->next(), "%name%|*|~") || (tok->next()->isKeyword() && !Token::Match(tok->next(), "new|delete|operator")))
+                syntaxError(tok);
+            if (Token::simpleMatch(tok->tokAt(-1), ")")) {
+                const Token* const prev = tok->linkAt(-1)->tokAt(-1);
+                if (!Token::Match(prev, "%name% (") || (!prev->isControlFlowKeyword() && prev->str() != "decltype")) {
+                    if (prev && prev->isUpperCaseName())
+                        unknownMacroError(prev);
+                    else
+                        syntaxError(tok);
+                }
+            }
+        }
         if (Token::Match(tok, "& %comp%|&&|%oror%|&|%or%") && tok->strAt(1) != ">")
             syntaxError(tok);
         if (Token::Match(tok, "%comp%|&&|%oror%|&|%or% }") && tok->str() != ">")

test/testsymboldatabase.cpp

@@ -3774,9 +3774,8 @@ class TestSymbolDatabase : public TestFixture {
     }
 
     void symboldatabase35() { // ticket #4806 and #4841
-        check("class FragmentQueue : public CL_NS(util)::PriorityQueue<CL_NS(util)::Deletor::Object<TextFragment> >\n"
-              "{};\n");
-        ASSERT_EQUALS("", errout_str());
+        ASSERT_THROW_INTERNAL(check("class FragmentQueue : public CL_NS(util)::PriorityQueue<CL_NS(util)::Deletor::Object<TextFragment> >\n"
+                                    "{};\n"), UNKNOWN_MACRO);
     }
 
     void symboldatabase36() { // ticket #4892

test/testtokenize.cpp

@@ -7919,6 +7919,16 @@ class TestTokenizer : public TestFixture {
                                                    "    return std::string{ g() + \"abc\" MACRO \"def\" };\n"
                                                    "}\n"), UNKNOWN_MACRO);
 
+        ASSERT_THROW_INTERNAL(tokenizeAndStringify("namespace N {\n"
+                                                   "    struct C {\n"
+                                                   "        void f();\n"
+                                                   "    };\n"
+                                                   "    void C(abc)::f() {\n"
+                                                   "        X x;\n"
+                                                   "        N::Y([&] { x(); })->g();\n"
+                                                   "    }\n"
+                                                   "}\n"), UNKNOWN_MACRO);
+
         ASSERT_THROW_INTERNAL_EQUALS(tokenizeAndStringify("static void handle_toggle(void (*proc) PROTO_XT_CALLBACK_ARGS, int var) {}\n"), // #13198
                                      UNKNOWN_MACRO,
                                      "There is an unknown macro here somewhere. Configuration is required. If PROTO_XT_CALLBACK_ARGS is a macro then please configure it.");