#6753 segmentation fault (invalid code) in CheckMemoryLeakStructMember::checkStructVariable. #6754 segmentation fault (invalid code) in CheckUnusedVar::checkFunctionVariableUsage_iterateScopes. Trivial fixes to avoid null pointer access

lib/checkmemoryleak.cpp

@@ -2520,7 +2520,7 @@ void CheckMemoryLeakStructMember::checkStructVariable(const Variable * const var
 
     // Check struct..
     unsigned int indentlevel2 = 0;
-    for (const Token *tok2 = variable->nameToken(); tok2 != variable->scope()->classEnd; tok2 = tok2->next()) {
+    for (const Token *tok2 = variable->nameToken(); tok2 && tok2 != variable->scope()->classEnd; tok2 = tok2->next()) {
         if (tok2->str() == "{")
             ++indentlevel2;
 

lib/checkunusedvar.cpp

@@ -440,7 +440,7 @@ static const Token* doAssignment(Variables &variables, const Token *tok, bool de
             tok = tok->next();
 
         if (Token::Match(tok, "(| &| %name%") ||
-            Token::Match(tok->next(), "< const| struct|union| %type% *| > ( &| %name%")) {
+            (tok && Token::Match(tok->next(), "< const| struct|union| %type% *| > ( &| %name%"))) {
             bool addressOf = false;
 
             if (Token::Match(tok, "%var% ."))
@@ -504,7 +504,7 @@ static const Token* doAssignment(Variables &variables, const Token *tok, bool de
 
             // check if variable is local
             unsigned int varid2 = tok->varId();
-            Variables::VariableUsage* var2 = variables.find(varid2);
+            const Variables::VariableUsage* var2 = variables.find(varid2);
 
             if (var2) { // local variable (alias or read it)
                 if (var1->_type == Variables::pointer || var1->_type == Variables::pointerArray) {
@@ -599,9 +599,9 @@ static const Token* doAssignment(Variables &variables, const Token *tok, bool de
     // check for alias to struct member
     // char c[10]; a.b = c;
     else if (Token::Match(tok->tokAt(-2), "%name% .")) {
-        if (tok->tokAt(2)->varId()) {
+        if (tok->tokAt(2) && tok->tokAt(2)->varId()) {
-            unsigned int varid2 = tok->tokAt(2)->varId();
+            const unsigned int varid2 = tok->tokAt(2)->varId();
-            Variables::VariableUsage *var2 = variables.find(varid2);
+            const Variables::VariableUsage *var2 = variables.find(varid2);
 
             // struct member aliased to local variable
             if (var2 && (var2->_type == Variables::array ||
@@ -616,7 +616,7 @@ static const Token* doAssignment(Variables &variables, const Token *tok, bool de
     // Possible pointer alias
     else if (Token::Match(tok, "%name% = %name% ;")) {
         const unsigned int varid2 = tok->tokAt(2)->varId();
-        Variables::VariableUsage *var2 = variables.find(varid2);
+        const Variables::VariableUsage *var2 = variables.find(varid2);
         if (var2 && (var2->_type == Variables::array ||
                      var2->_type == Variables::pointer)) {
             variables.use(varid2,tok);

test/testgarbage.cpp

@@ -113,6 +113,8 @@ private:
         TEST_CASE(garbageCode72);
         TEST_CASE(garbageCode73);
         TEST_CASE(garbageCode74);
+        TEST_CASE(garbageCode75);
+        TEST_CASE(garbageCode76);
 
         TEST_CASE(garbageValueFlow);
         TEST_CASE(garbageSymbolDatabase);
@@ -630,6 +632,14 @@ private:
         checkCode("_lenraw(const char* digits) { } typedef decltype(sizeof(0)) { } operator");
     }
 
+    void garbageCode75() { // #6753
+        checkCode("{ { void foo() { struct }; { }; } }; struct S { } f =", "test.c");
+    }
+
+    void garbageCode76() { // #6754
+        checkCode(" ( ) ( ) { ( ) [ ] } TEST ( ) { ( _broadcast_f32x4 ) ( ) ( ) ( ) ( ) if ( ) ( ) ; } E mask = ( ) [ ] ( ) res1.x =");
+    }
+
     void garbageValueFlow() {
         // #6089
         const char* code = "{} int foo(struct, x1, struct x2, x3, int, x5, x6, x7)\n"