Declarations4: improve RULE-8-2

Author: knewbury01

c/misra/src/rules/RULE-8-2/FunctionTypesNotInPrototypeForm.ql

@@ -22,6 +22,20 @@ class UnnamedParameter extends Parameter {
   UnnamedParameter() { not this.isNamed() }
 }
 
+/*
+ * This is a copy of the private `hasZeroParamDecl` predicate from the standard set of
+ * queries as of the `codeql-cli/2.11.2` tag in `github/codeql`.
+ */
+
+predicate hasZeroParamDecl(Function f) {
+  exists(FunctionDeclarationEntry fde | fde = f.getADeclarationEntry() |
+    not fde.isImplicit() and
+    not fde.hasVoidParamList() and
+    fde.getNumberOfParameters() = 0 and
+    not fde.isDefinition()
+  )
+}
+
 from Function f, string msg
 where
   not isExcluded(f, Declarations4Package::functionTypesNotInPrototypeFormQuery()) and
@@ -30,11 +44,8 @@ where
     f.getAParameter() instanceof UnnamedParameter and
     msg = "Function " + f + " declares parameter that is unnamed."
     or
-    //void keyword not present in function signature, no way to tell which
-    not exists(f.getAParameter()) and
-    msg =
-      "Function " + f +
-        " may not specify all parameter types or may not specifiy void for no parameters present."
+    hasZeroParamDecl(f) and
+    msg = "Function " + f + " does not specifiy void for no parameters present."
     or
     exists(Parameter p |
       p.getFunction() = f and

c/misra/test/rules/RULE-8-2/FunctionTypesNotInPrototypeForm.expected

@@ -1,5 +1,4 @@
-| test.c:2:6:2:7 | f0 | Function f0 may not specify all parameter types or may not specifiy void for no parameters present. |
 | test.c:3:6:3:7 | f1 | Function f1 declares parameter that is unnamed. |
-| test.c:4:6:4:7 | f2 | Function f2 may not specify all parameter types or may not specifiy void for no parameters present. |
-| test.c:5:6:5:7 | f3 | Function f3 may not specify all parameter types or may not specifiy void for no parameters present. |
+| test.c:4:6:4:7 | f2 | Function f2 does not specifiy void for no parameters present. |
+| test.c:5:6:5:7 | f3 | Function f3 does not specifiy void for no parameters present. |
 | test.c:7:5:7:6 | f5 | Function f5 declares parameter in unsupported declaration list. |

c/misra/test/rules/RULE-8-2/test.c

@@ -1,5 +1,5 @@
 void f(int x);    // COMPLIANT
-void f0(void);    // COMPLIANT[FALSE_POSITIVE]
+void f0(void);    // COMPLIANT
 void f1(int);     // NON_COMPLIANT
 void f2();        // NON_COMPLIANT
 void f3(x);       // NON_COMPLIANT