Swift: Introduce EnumElmentDecl.hasQualifiedName and use it to clean up the code.

Author: geoffw0

swift/ql/lib/codeql/swift/elements/decl/EnumElementDecl.qll

@@ -1,5 +1,38 @@
 private import codeql.swift.generated.decl.EnumElementDecl
+private import codeql.swift.elements.decl.Decl
 
+/**
+ * An enum element declaration, for example `enumElement` and `anotherEnumElement` in:
+ * ```
+ * enum MyEnum {
+ *   case enumElement
+ *   case anotherEnumElement(Int)
+ * }
+ * ```
+ */
 class EnumElementDecl extends Generated::EnumElementDecl {
   override string toString() { result = this.getName() }
+
+  /**
+   * Holds if this function is called `funcName` and is a member of a
+   * class, struct, extension, enum or protocol called `typeName`.
+   */
+  cached
+  predicate hasQualifiedName(string typeName, string enumElementName) {
+    this.getName() = enumElementName and
+    exists(Decl d |
+      d.asNominalTypeDecl().getFullName() = typeName and
+      d.getAMember() = this
+    )
+  }
+
+  /**
+   * Holds if this function is called `funcName` and is a member of a
+   * class, struct, extension, enum or protocol called `typeName` in a module
+   * called `moduleName`.
+   */
+  predicate hasQualifiedName(string moduleName, string typeName, string enumElementName) {
+    this.hasQualifiedName(typeName, enumElementName) and
+    this.getModule().getFullName() = moduleName
+  }
 }

swift/ql/lib/codeql/swift/elements/expr/EnumElementExpr.qll

@@ -10,7 +10,14 @@ private import codeql.swift.elements.expr.MethodLookupExpr
 private import codeql.swift.elements.decl.EnumElementDecl
 
 /**
- * An expression that constructs a case of an enum.
+ * An expression that references a case of an enum. For example both `enumElement` in:
+ * ```
+ * let value = MyEnum.enumElement
+ * ...
+ * switch (anotherValue) {
+ *   case .enumElement:
+ *   ...
+ * ```
  */
 class EnumElementExpr extends Expr {
   EnumElementDecl decl;

swift/ql/lib/codeql/swift/security/PathInjectionExtensions.qll

@@ -53,12 +53,9 @@ private class GlobalVariablePathInjectionSink extends PathInjectionSink {
 private class EnumConstructorPathInjectionSink extends PathInjectionSink {
   EnumConstructorPathInjectionSink() {
     // first argument to `Connection.Location.uri(_:parameters:)`
-    exists(ApplyExpr ae, EnumElementDecl decl, NominalTypeDecl parent |
+    exists(ApplyExpr ae, EnumElementDecl decl |
       ae.getFunction().(MethodLookupExpr).getMember() = decl and
-      decl.getName() = "uri" and
-      decl.getDeclaringDecl() = parent and
-      parent.getName() = "Location" and
-      parent.getDeclaringDecl().(NominalTypeDecl).(NominalTypeDecl).getName() = "Connection" and
+      decl.hasQualifiedName("Connection.Location", "uri") and
       this.asExpr() = ae.getArgument(0).getExpr()
     )
   }