Fix #14033 Crash in CheckClass::checkConst() (#7695)

Author: chrchr-github

lib/checkclass.cpp

@@ -2192,7 +2192,11 @@ void CheckClass::checkConst()
             if (suggestStatic && func.isConst()) {
                 const auto overloads = func.getOverloadedFunctions();
                 if (overloads.size() > 1 && std::any_of(overloads.begin(), overloads.end(), [&](const Function* ovl) {
-                    return &func != ovl && func.argCount() == ovl->argCount() && func.argsMatch(ovl->functionScope, ovl->argDef, func.argDef, emptyString, 0);
+                    if (&func == ovl)
+                        return false;
+                    if (!ovl->functionScope)
+                        return true;
+                    return func.argCount() == ovl->argCount() && func.argsMatch(ovl->functionScope, ovl->argDef, func.argDef, emptyString, 0);
                 }))
                     continue;
             }

test/testclass.cpp

@@ -6863,6 +6863,12 @@ class TestClass : public TestFixture {
                    "    int i;\n"
                    "};\n");
         ASSERT_EQUALS("", errout_str());
+
+        checkConst("struct S {\n" // #14033
+                   "    void f();\n"
+                   "    void f() const {}\n"
+                   "};\n");
+        ASSERT_EQUALS("", errout_str()); // don't crash
     }
 
     void const_handleDefaultParameters() {