Declarations3: add RULE-5-7 and fix testcase RULE-5-6

Author: knewbury01

c/common/src/codingstandards/c/Identifiers.qll

@@ -0,0 +1,14 @@
+import cpp
+
+//Identifiers that are candidates for checking uniqueness
+class InterestingIdentifiers extends Declaration {
+    InterestingIdentifiers() {
+      not this.isFromTemplateInstantiation(_) and
+      not this.isFromUninstantiatedTemplate(_) and
+      not this instanceof TemplateParameter and
+      not this.hasDeclaringType() and
+      not this instanceof Operator and
+      not this.hasName("main") and
+      exists(this.getADeclarationLocation())
+    }
+  }

c/misra/src/rules/RULE-5-6/TypedefNameNotUnique.ql

@@ -14,19 +14,7 @@
 
 import cpp
 import codingstandards.c.misra
-
-//exception cases additional to rule description
-class InterestingIdentifiers extends Declaration {
-  InterestingIdentifiers() {
-    not this.isFromTemplateInstantiation(_) and
-    not this.isFromUninstantiatedTemplate(_) and
-    not this instanceof TemplateParameter and
-    not this.hasDeclaringType() and
-    not this instanceof Operator and
-    not this.hasName("main") and
-    exists(this.getADeclarationLocation())
-  }
-}
+import codingstandards.c.Identifiers
 
 from TypedefType t, InterestingIdentifiers d
 where

c/misra/src/rules/RULE-5-7/TagNameNotUnique.ql

@@ -0,0 +1,28 @@
+/**
+ * @id c/misra/tag-name-not-unique
+ * @name RULE-5-7: A tag name shall be a unique identifier
+ * @description Reusing a tag name compared to the name of any tag can cause confusion and make code
+ *              harder to read.
+ * @kind problem
+ * @precision very-high
+ * @problem.severity error
+ * @tags external/misra/id/rule-5-7
+ *       readability
+ *       maintainability
+ *       external/misra/obligation/required
+ */
+
+import cpp
+import codingstandards.c.misra
+import codingstandards.c.Identifiers
+
+from Struct s, InterestingIdentifiers s2
+where
+  not isExcluded(s, Declarations3Package::tagNameNotUniqueQuery()) and
+  not isExcluded(s2, Declarations3Package::tagNameNotUniqueQuery()) and
+  not s = s2 and
+  s.getName() = s2.getName() and
+  not s.getName() = "struct <unnamed>" and
+  not s.getName() = "union <unnamed>" and
+  not s.getName() = s2.(TypedefType).getBaseType().toString()
+select s, "Tag name is nonunique compared to $@.", s2, s2.getName()

c/misra/test/rules/RULE-5-6/test.c

@@ -27,6 +27,4 @@ typedef struct {
     int ii;
   } s1;
   int i;
-} chain; // NON_COMPLIANT
-
-typedef void (*pointercase)(int i); // COMPLIANT
+} chain; // NON_COMPLIANT

c/misra/test/rules/RULE-5-7/TagNameNotUnique.expected

@@ -0,0 +1,4 @@
+| test.c:5:8:5:9 | s1 | Tag name is nonunique compared to $@. | test.c:12:10:12:11 | s1 | s1 |
+| test.c:5:8:5:9 | s1 | Tag name is nonunique compared to $@. | test.c:17:17:17:18 | s1 | s1 |
+| test.c:12:10:12:11 | s1 | Tag name is nonunique compared to $@. | test.c:5:8:5:9 | s1 | s1 |
+| test.c:12:10:12:11 | s1 | Tag name is nonunique compared to $@. | test.c:17:17:17:18 | s1 | s1 |

c/misra/test/rules/RULE-5-7/TagNameNotUnique.qlref

@@ -0,0 +1 @@
+rules/RULE-5-7/TagNameNotUnique.ql

c/misra/test/rules/RULE-5-7/test.c

@@ -0,0 +1,33 @@
+typedef struct s {
+  int i;
+} s; // COMPLIANT
+
+struct s1 { // NON_COMPLIANT
+  int i;
+};
+
+struct s1 a1 = {0}; // COMPLIANT
+
+void f() {
+  struct s1 { // NON_COMPLIANT
+    int i;
+  };
+}
+
+void f1() { int s1 = 0; }
+
+typedef struct {
+  int i;
+} sunnamed; // COMPLIANT
+
+typedef struct {
+  int i;
+} sunnamed2; // COMPLIANT
+
+typedef union {
+  int i;
+} U; // COMPLIANT
+
+typedef union {
+  int i;
+}; // COMPLIANT

cpp/common/src/codingstandards/cpp/exclusions/c/Declarations3.qll

@@ -5,7 +5,8 @@ import codingstandards.cpp.exclusions.RuleMetadata
 
 newtype Declarations3Query =
   TIdentifierHidingCQuery() or
-  TTypedefNameNotUniqueQuery()
+  TTypedefNameNotUniqueQuery() or
+  TTagNameNotUniqueQuery()
 
 predicate isDeclarations3QueryMetadata(Query query, string queryId, string ruleId) {
   query =
@@ -23,6 +24,14 @@ predicate isDeclarations3QueryMetadata(Query query, string queryId, string ruleI
     // `@id` for the `typedefNameNotUnique` query
     "c/misra/typedef-name-not-unique" and
   ruleId = "RULE-5-6"
+  or
+  query =
+    // `Query` instance for the `tagNameNotUnique` query
+    Declarations3Package::tagNameNotUniqueQuery() and
+  queryId =
+    // `@id` for the `tagNameNotUnique` query
+    "c/misra/tag-name-not-unique" and
+  ruleId = "RULE-5-7"
 }
 
 module Declarations3Package {
@@ -39,4 +48,11 @@ module Declarations3Package {
       // `Query` type for `typedefNameNotUnique` query
       TQueryC(TDeclarations3PackageQuery(TTypedefNameNotUniqueQuery()))
   }
+
+  Query tagNameNotUniqueQuery() {
+    //autogenerate `Query` type
+    result =
+      // `Query` type for `tagNameNotUnique` query
+      TQueryC(TDeclarations3PackageQuery(TTagNameNotUniqueQuery()))
+  }
 }

rule_packages/c/Declarations3.json

@@ -43,6 +43,26 @@
         }
       ],
       "title": "A typedef name shall be a unique identifier"
+    },
+    "RULE-5-7": {
+      "properties": {
+        "obligation": "required"
+      },
+      "queries": [
+        {
+          "description": "Reusing a tag name compared to the name of any tag can cause confusion and make code harder to read.",
+          "kind": "problem",
+          "name": "A tag name shall be a unique identifier",
+          "precision": "very-high",
+          "severity": "error",
+          "short_name": "TagNameNotUnique",
+          "tags": [
+            "readability",
+            "maintainability"
+          ]
+        }
+      ],
+      "title": "A tag name shall be a unique identifier"
     }
   }
 }

rules.csv

@@ -637,7 +637,7 @@ c,MISRA-C-2012,RULE-5-3,Yes,Required,,,An identifier declared in an inner scope
 c,MISRA-C-2012,RULE-5-4,Yes,Required,,,Macro identifiers shall be distinct,,Declarations1,Easy,
 c,MISRA-C-2012,RULE-5-5,Yes,Required,,,Identifiers shall be distinct from macro names,,Declarations,Easy,
 c,MISRA-C-2012,RULE-5-6,Yes,Required,,,A typedef name shall be a unique identifier,,Declarations3,Easy,
-c,MISRA-C-2012,RULE-5-7,Yes,Required,,,A tag name shall be a unique identifier,,Declarations,Easy,
+c,MISRA-C-2012,RULE-5-7,Yes,Required,,,A tag name shall be a unique identifier,,Declarations3,Easy,
 c,MISRA-C-2012,RULE-5-8,Yes,Required,,,Identifiers that define objects or functions with external linkage shall be unique,,Declarations,Easy,
 c,MISRA-C-2012,RULE-5-9,Yes,Advisory,,,Identifiers that define objects or functions with internal linkage should be unique,,Declarations,Easy,
 c,MISRA-C-2012,RULE-6-1,Yes,Required,,,Bit-fields shall only be declared with an appropriate type,M9-6-4,Types,Medium,