#7257 segmentation fault in valueFlowSwitchVariable (invalid code). Correct SymbolDatabase::validateVariables() so it does not complain about function arguments for function without body

lib/symboldatabase.cpp

@@ -1390,11 +1390,36 @@ void SymbolDatabase::validateExecutableScopes() const
     }
 }
 
+namespace {
+    const Function* getFunctionForArgumentvariable(const Variable * const var, const std::vector<const Scope *>& functionScopes)
+    {
+        const std::size_t functions = functionScopes.size();
+        for (std::size_t i = 0; i < functions; ++i) {
+            const Scope* const scope = functionScopes[i];
+            const Function* const function = scope->function;
+            if (function) {
+                for (std::size_t arg=0; arg < function->argCount(); ++arg) {
+                    if (var==function->getArgumentVar(arg))
+                        return function;
+                }
+            }
+        }
+        return nullptr;
+    }
+}
+
 void SymbolDatabase::validateVariables() const
 {
     for (std::vector<const Variable *>::const_iterator iter = _variableList.begin(); iter!=_variableList.end(); ++iter) {
-        if (*iter && !(*iter)->scope()) {
-            throw InternalError((*iter)->nameToken(), "Analysis failed (variable without scope). If the code is valid then please report this failure.", InternalError::INTERNAL);
+        if (*iter) {
+            const Variable * const var = *iter;
+            if (!var->scope()) {
+                const Function* function = getFunctionForArgumentvariable(var, functionScopes);
+                if (!var->isArgument() || (function && function->hasBody())) {
+                    throw InternalError(var->nameToken(), "Analysis failed (variable without scope). If the code is valid then please report this failure.", InternalError::INTERNAL);
+                    //std::cout << "!!!Variable found without scope: " << var->nameToken()->str() << std::endl;
+                }
+            }
         }
     }
 }

lib/valueflow.cpp

@@ -2206,7 +2206,8 @@ static void valueFlowSwitchVariable(TokenList *tokenlist, SymbolDatabase* symbol
                                      errorLogger,
                                      settings);
                 }
-                valueFlowForward(tok, vartok->variable()->scope()->classEnd, vartok->variable(), vartok->varId(), values, false, tokenlist, errorLogger, settings);
+                if (vartok->variable()->scope()) // #7257
+                    valueFlowForward(tok, vartok->variable()->scope()->classEnd, vartok->variable(), vartok->varId(), values, false, tokenlist, errorLogger, settings);
             }
         }
     }

test/testgarbage.cpp

@@ -224,6 +224,7 @@ private:
         TEST_CASE(garbageCode173); // #6781
         TEST_CASE(garbageCode174); // #7356
         TEST_CASE(garbageCode175);
+        TEST_CASE(garbageCode176);
         TEST_CASE(garbageValueFlow);
         TEST_CASE(garbageSymbolDatabase);
         TEST_CASE(garbageAST);
@@ -1474,6 +1475,10 @@ private:
                                "        return t1 ,\n"
                                "}"), InternalError);
     }
+
+    void garbageCode176() { // #7527
+        checkCode("class t { { struct } enum class f : unsigned { q } b ; operator= ( T ) { switch ( b ) { case f::q: } } { assert ( b ) ; } } { ; & ( t ) ( f::t ) ; } ;");
+    }
 };
 
 REGISTER_TEST(TestGarbage)