Remove overhead of existentials

Author: ahoppen

Sources/SwiftSyntax/RawSyntax.swift

@@ -1164,6 +1164,8 @@ final class RawSyntax: ManagedBuffer<RawSyntaxBase, RawSyntaxDataElement> {
   ///         is returned.
   /// - Parameter newLayout: The children of the new node you're creating.
   func replacingLayout(_ newLayout: [RawSyntax?]) -> RawSyntax {
+    // FIXME: We should make sure that the new layout is valid for this node 
+    // type.
     if isToken { return self }
     return .createAndCalcLength(kind: kind, layout: newLayout, presence: presence)
   }

Sources/SwiftSyntax/SourceLocation.swift

@@ -227,8 +227,14 @@ public final class SourceLocationConverter {
   }
 }
 
-extension _SyntaxBase {
-  func startLocation(
+extension Syntax {
+  /// The starting location, in the provided file, of this Syntax node.
+  /// - Parameters:
+  ///   - converter: The `SourceLocationConverter` that was previously
+  ///     initialized using the root tree of this node.
+  ///   - afterLeadingTrivia: Whether to skip leading trivia when getting
+  ///                         the node's location. Defaults to `true`.
+  public func startLocation(
     converter: SourceLocationConverter,
     afterLeadingTrivia: Bool = true
   ) -> SourceLocation {
@@ -238,7 +244,13 @@ extension _SyntaxBase {
     return converter.location(for: pos)
   }
 
-  func endLocation(
+  /// The ending location, in the provided file, of this Syntax node.
+  /// - Parameters:
+  ///   - converter: The `SourceLocationConverter` that was previously
+  ///     initialized using the root tree of this node.
+  ///   - afterTrailingTrivia: Whether to skip trailing trivia when getting
+  ///                          the node's location. Defaults to `false`.
+  public func endLocation(
     converter: SourceLocationConverter,
     afterTrailingTrivia: Bool = false
   ) -> SourceLocation {
@@ -251,7 +263,15 @@ extension _SyntaxBase {
     return converter.location(for: pos)
   }
 
-  func sourceRange(
+  /// The source range, in the provided file, of this Syntax node.
+  /// - Parameters:
+  ///   - converter: The `SourceLocationConverter` that was previously
+  ///     initialized using the root tree of this node.
+  ///   - afterLeadingTrivia: Whether to skip leading trivia when getting
+  ///                          the node's start location. Defaults to `true`.
+  ///   - afterTrailingTrivia: Whether to skip trailing trivia when getting
+  ///                          the node's end location. Defaults to `false`.
+  public func sourceRange(
     converter: SourceLocationConverter,
     afterLeadingTrivia: Bool = true,
     afterTrailingTrivia: Bool = false
@@ -262,19 +282,19 @@ extension _SyntaxBase {
   }
 }
 
-extension Syntax {
+public extension _SpecializedSyntaxMixin {
   /// The starting location, in the provided file, of this Syntax node.
   /// - Parameters:
   ///   - converter: The `SourceLocationConverter` that was previously
   ///     initialized using the root tree of this node.
   ///   - afterLeadingTrivia: Whether to skip leading trivia when getting
   ///                         the node's location. Defaults to `true`.
-  public func startLocation(
+  func startLocation(
     converter: SourceLocationConverter,
     afterLeadingTrivia: Bool = true
   ) -> SourceLocation {
-    return base.startLocation(converter: converter,
-      afterLeadingTrivia: afterLeadingTrivia)
+    return self.asSyntax.startLocation(converter: converter, 
+                                       afterLeadingTrivia: afterLeadingTrivia)
   }
 
   /// The ending location, in the provided file, of this Syntax node.
@@ -283,12 +303,12 @@ extension Syntax {
   ///     initialized using the root tree of this node.
   ///   - afterTrailingTrivia: Whether to skip trailing trivia when getting
   ///                          the node's location. Defaults to `false`.
-  public func endLocation(
+  func endLocation(
     converter: SourceLocationConverter,
     afterTrailingTrivia: Bool = false
   ) -> SourceLocation {
-    return base.endLocation(converter: converter,
-      afterTrailingTrivia: afterTrailingTrivia)
+    return self.asSyntax.endLocation(converter: converter, 
+                                     afterTrailingTrivia: afterTrailingTrivia)
   }
 
   /// The source range, in the provided file, of this Syntax node.
@@ -299,14 +319,14 @@ extension Syntax {
   ///                          the node's start location. Defaults to `true`.
   ///   - afterTrailingTrivia: Whether to skip trailing trivia when getting
   ///                          the node's end location. Defaults to `false`.
-  public func sourceRange(
+  func sourceRange(
     converter: SourceLocationConverter,
     afterLeadingTrivia: Bool = true,
     afterTrailingTrivia: Bool = false
   ) -> SourceRange {
-    return base.sourceRange(converter: converter,
-      afterLeadingTrivia: afterLeadingTrivia,
-      afterTrailingTrivia: afterTrailingTrivia)
+    return self.asSyntax.sourceRange(converter: converter, 
+                                    afterLeadingTrivia: afterLeadingTrivia,
+                                    afterTrailingTrivia: afterTrailingTrivia)
   }
 }