Rule 8.13: Correctly handle assignment into structs

Author: lcartey

c/misra/src/rules/RULE-8-13/PointerShouldPointToConstTypeWhenPossible.ql

@@ -41,8 +41,8 @@ class NonConstPointerVariableCandidate extends Variable {
     not exists(VariableEffect effect |
       effect.getTarget() = this and
       // but not pointers that are only themselves modified
-      not effect.(AssignExpr).getLValue() = effect.getAnAccess() and
-      not effect.(CrementOperation).getOperand() = effect.getAnAccess()
+      not effect.(AssignExpr).getLValue() = this.getAnAccess() and
+      not effect.(CrementOperation).getOperand() = this.getAnAccess()
     ) and
     // exclude pointers assigned to another pointer to a non-const-qualified type
     not exists(Variable a |

c/misra/test/rules/RULE-8-13/PointerShouldPointToConstTypeWhenPossible.expected

@@ -12,3 +12,4 @@
 | test.c:66:23:66:24 | p1 | $@ points to a non-const-qualified type. | test.c:66:23:66:24 | p1 | p1 |
 | test.c:71:17:71:18 | p1 | $@ points to a non-const-qualified type. | test.c:71:17:71:18 | p1 | p1 |
 | test.c:75:15:75:16 | p1 | $@ points to a non-const-qualified type. | test.c:75:15:75:16 | p1 | p1 |
+| test.c:97:30:97:30 | s | $@ points to a non-const-qualified type. | test.c:97:30:97:30 | s | s |

c/misra/test/rules/RULE-8-13/test.c

@@ -84,4 +84,16 @@ test_r(int16_t *value) { // COMPLIANT - ignored because of the use of ASM
   int16_t result;
   __asm__("movb %bh (%eax)");
   return result;
+}
+
+struct S {
+  int x;
+};
+
+void test_struct(struct S *s) { // COMPLIANT
+  s->x = 1;
+}
+
+void test_struct_2(struct S *s) { // NON_COMPLIANT - could be const
+  s = 0;
 }