Conform NamedDeclSyntax to DeclSyntaxProtocol

This is accurate for all NamedDeclSyntax conformers so far, so I feel comfortable doing it.

This also improves the accuracy of the “conforms if it can” validation by also checking the trait’s base kind against the node. That eliminates several false positives in the test.

Author: beccadax

CodeGeneration/Sources/SyntaxSupport/Traits.swift

@@ -103,6 +103,7 @@ public let TRAITS: [Trait] = [
   ),
   Trait(
     traitName: "NamedDecl",
+    baseKind: .decl,
     children: [
       Child(name: "name", kind: .token(choices: [.token(.identifier)]))
     ]

CodeGeneration/Tests/ValidateSyntaxNodes/ValidateSyntaxNodes.swift

@@ -116,6 +116,30 @@ fileprivate extension Array where Element: Hashable, Element: Comparable {
   }
 }
 
+extension LayoutNode {
+  /// True if `self` satisfies all of the requirements of `trait`, regardless
+  /// of whether it actually declares conformance to it.
+  func canConform(to trait: Trait) -> Bool {
+    if let traitBaseKind = trait.baseKind {
+      guard traitBaseKind == self.base else {
+        return false
+      }
+    }
+
+    return trait.children.allSatisfy { traitChild in
+      self.children.contains { nodeChild in
+        traitChild.hasSameType(as: nodeChild)
+      }
+    }
+  }
+
+  /// True if `self` declares conformance to `trait`, regardless of whether
+  /// it satisfies the trait's requirements.
+  func conforms(to trait: Trait) -> Bool {
+    self.traits.contains(trait.traitName)
+  }
+}
+
 class ValidateSyntaxNodes: XCTestCase {
   /// All nodes with base kind e.g. `ExprSyntax` should end with `ExprSyntax`.
   func testBaseKindSuffix() {
@@ -514,12 +538,7 @@ class ValidateSyntaxNodes: XCTestCase {
 
     for node in SYNTAX_NODES.compactMap(\.layoutNode) {
       for trait in TRAITS {
-        let canConformToTrait = trait.children.allSatisfy { traitChild in
-          node.children.contains { nodeChild in
-            traitChild.hasSameType(as: nodeChild)
-          }
-        }
-        if canConformToTrait && !node.traits.contains(trait.traitName) {
+        if node.canConform(to: trait) && !node.conforms(to: trait) {
           failures.append(
             ValidationFailure(
               node: node.kind,
@@ -533,7 +552,6 @@ class ValidateSyntaxNodes: XCTestCase {
     assertFailuresMatchXFails(
       failures,
       expectedFailures: [
-        ValidationFailure(node: .accessorParameters, message: "could conform to trait 'NamedDecl' but does not"),
         ValidationFailure(node: .availabilityCondition, message: "could conform to trait 'Parenthesized' but does not"),
         ValidationFailure(node: ._canImportExpr, message: "could conform to trait 'Parenthesized' but does not"),
         ValidationFailure(
@@ -542,10 +560,6 @@ class ValidateSyntaxNodes: XCTestCase {
         ),
         ValidationFailure(node: .editorPlaceholderDecl, message: "could conform to trait 'MissingNode' but does not"),
         ValidationFailure(node: .editorPlaceholderExpr, message: "could conform to trait 'MissingNode' but does not"),
-        ValidationFailure(node: .enumCaseElement, message: "could conform to trait 'NamedDecl' but does not"),
-        ValidationFailure(node: .genericParameter, message: "could conform to trait 'NamedDecl' but does not"),
-        ValidationFailure(node: .precedenceGroupName, message: "could conform to trait 'NamedDecl' but does not"),
-        ValidationFailure(node: .primaryAssociatedType, message: "could conform to trait 'NamedDecl' but does not"),
         ValidationFailure(
           node: .yieldedExpressionsClause,
           message: "could conform to trait 'Parenthesized' but does not"

Sources/SwiftSyntax/generated/SyntaxTraits.swift

@@ -278,7 +278,7 @@ extension SyntaxProtocol {
 
 // MARK: - NamedDeclSyntax
 
-public protocol NamedDeclSyntax: SyntaxProtocol {
+public protocol NamedDeclSyntax: SyntaxProtocol, DeclSyntaxProtocol {
   /// ### Tokens
   /// 
   /// For syntax trees generated by the parser, this is guaranteed to be `<identifier>`.