Declarations1: add testcases and improve type logic for DCL31-C

Author: knewbury01

c/cert/src/rules/DCL31-C/DeclareIdentifiersBeforeUsingThem.ql

@@ -1,7 +1,8 @@
 /**
  * @id c/cert/declare-identifiers-before-using-them
  * @name DCL31-C: Declare identifiers before using them
- * @description Omission of type specifiers may not be supported by some compilers.
+ * @description Omission of type specifiers may not be supported by some
+ * compilers.
  * @kind problem
  * @precision very-high
  * @problem.severity error
@@ -17,5 +18,12 @@ import codingstandards.c.cert
 from Declaration d
 where
   not isExcluded(d, Declarations1Package::declareIdentifiersBeforeUsingThemQuery()) and
-  d.hasSpecifier("implicit_int")
+  d.hasSpecifier("implicit_int") and
+  exists(Type t |
+    (d.(Variable).getType() = t or d.(Function).getType() = t) and
+    // Exclude "short" or "long", as opposed to "short int" or "long int".
+    t instanceof IntType and
+    // Exclude "signed" or "unsigned", as opposed to "signed int" or "unsigned int".
+    not exists(IntegralType it | it = t | it.isExplicitlySigned() or it.isExplicitlyUnsigned())
+  )
 select d, "Declaration is missing a type specifier."

c/cert/test/rules/DCL31-C/DeclareIdentifiersBeforeUsingThem.expected

@@ -1,2 +1,2 @@
-| test.c:2:8:2:8 | g | Declaration is missing a type specifier. |
-| test.c:6:1:6:1 | f | Declaration is missing a type specifier. |
+| test.c:1:8:1:8 | g | Declaration is missing a type specifier. |
+| test.c:5:1:5:1 | f | Declaration is missing a type specifier. |

c/cert/test/rules/DCL31-C/test.c

@@ -1,4 +1,3 @@
-
 extern g; // NON_COMPLIANT
 
 extern int g1; // COMPLIANT
@@ -9,4 +8,8 @@ f(void) { // NON_COMPLIANT
 
 int f1(void) { // COMPLIANT
   return 1;
-}
+}
+
+short g2;                 // COMPLIANT
+long g3;                  // COMPLIANT
+signed g4() { return 1; } // COMPLIANT