Resolve RULE-11-1 false-negative

Author: Nikita Kraiouchkine

c/misra/src/rules/RULE-11-1/ConversionBetweenFunctionPointerAndOtherType.ql

@@ -25,11 +25,5 @@ where
   // exception 1 (null pointer constant)
   not isNullPointerConstant(cast.getExpr()) and
   // exception 2 (conversion to void)
-  not newType instanceof VoidType and
-  // exception 3 (implicit conversion of function to function pointer)
-  not (
-    cast.isImplicit() and
-    newType instanceof FunctionPointerType and
-    cast.getExpr() instanceof FunctionAccess
-  )
+  not newType instanceof VoidType
 select cast, "Cast performed between a function pointer and another type."

c/misra/test/rules/RULE-11-1/ConversionBetweenFunctionPointerAndOtherType.expected

@@ -3,3 +3,4 @@
 | test.c:12:14:12:23 | (void *)... | Cast performed between a function pointer and another type. |
 | test.c:14:8:14:15 | (fp2)... | Cast performed between a function pointer and another type. |
 | test.c:15:8:15:15 | (fp2)... | Cast performed between a function pointer and another type. |
+| test.c:22:12:22:13 | (fp1)... | Cast performed between a function pointer and another type. |

c/misra/test/rules/RULE-11-1/test.c

@@ -18,6 +18,11 @@ void f1(void) {
   (void)(*v4()); // COMPLIANT
 
   extern void f2(int p1);
-  f2(0);       // COMPLIANT
-  fp1 v5 = f2; // COMPLIANT
+  f2(0);                   // COMPLIANT
+  fp1 v5 = f2;             // NON_COMPLIANT
+  fp2 v6 = f2;             // COMPLIANT
+  v5 = v1;                 // COMPLIANT
+  v5 = v2;                 // NON_COMPLIANT
+  v5 = (void (*)(void))v1; // COMPLIANT
+  v5 = (void (*)(void))v2; // NON_COMPLIANT
 }

change_notes/2022-08-12-fix-RULE-11-1-false-negative.md

@@ -0,0 +1,3 @@
+ - `RULE-11-1` - `ConversionBetweenFunctionPointerAndOtherType.ql`:
+   - A result is now reported for an implicit conversion of a pointer to a function into a pointer to a function with an incompatible type.
+   - Modified the test to reflect the fixed coverage.