[Macros] Remove the ConformanceMacro protocol.

Author: hborla

Examples/Sources/ExamplePlugin/Macros.swift

@@ -76,13 +76,16 @@ struct MemberDeprecatedMacro: MemberAttributeMacro {
 }
 
 /// Add 'Equatable' conformance.
-struct EquatableConformanceMacro: ConformanceMacro {
+struct EquatableConformanceMacro: ExtensionMacro {
   static func expansion(
     of node: AttributeSyntax,
-    providingConformancesOf declaration: some DeclGroupSyntax,
+    attachedTo declaration: some DeclGroupSyntax,
+    providingExtensionsOf type: some TypeSyntaxProtocol,
+    conformingTo protocols: [TypeSyntax],
     in context: some MacroExpansionContext
-  ) throws -> [(TypeSyntax, GenericWhereClauseSyntax?)] {
-    return [("Equatable", nil)]
+  ) throws -> [ExtensionDeclSyntax] {
+    let ext: DeclSyntax = "extension \(type.trimmed): Equatable {}"
+    return [ext.cast(ExtensionDeclSyntax.self)]
   }
 }
 

Sources/SwiftSyntaxMacros/CMakeLists.txt

@@ -10,7 +10,6 @@ add_swift_host_library(SwiftSyntaxMacros
   MacroProtocols/AccessorMacro.swift
   MacroProtocols/AttachedMacro.swift
   MacroProtocols/CodeItemMacro.swift
-  MacroProtocols/ConformanceMacro.swift
   MacroProtocols/DeclarationMacro.swift
   MacroProtocols/ExpressionMacro.swift
   MacroProtocols/ExtensionMacro.swift

Sources/SwiftSyntaxMacros/MacroProtocols/ConformanceMacro.swift

@@ -642,16 +642,6 @@ public struct DeclsFromStringsMacro: DeclarationMacro, MemberMacro {
   }
 }
 
-public struct SendableConformanceMacro: ConformanceMacro {
-  public static func expansion(
-    of node: AttributeSyntax,
-    providingConformancesOf declaration: some DeclGroupSyntax,
-    in context: some MacroExpansionContext
-  ) throws -> [(TypeSyntax, GenericWhereClauseSyntax?)] {
-    return [("Sendable", nil)]
-  }
-}
-
 public struct SendableExtensionMacro: ExtensionMacro {
   public static func expansion(
     of node: AttributeSyntax,
@@ -717,7 +707,6 @@ public let testMacros: [String: Macro.Type] = [
   "wrapStoredProperties": WrapStoredProperties.self,
   "customTypeWrapper": CustomTypeWrapperMacro.self,
   "unwrap": UnwrapMacro.self,
-  "AddSendable": SendableConformanceMacro.self,
   "AddSendableExtension": SendableExtensionMacro.self,
 ]
 
@@ -1537,44 +1526,6 @@ final class MacroSystemTests: XCTestCase {
     )
   }
 
-  func testConformanceExpansion() {
-    assertMacroExpansion(
-      """
-      @AddSendable
-      struct MyType {
-      }
-      """,
-      expandedSource: """
-
-        struct MyType {
-        }
-
-        extension MyType: Sendable {
-        }
-        """,
-      macros: testMacros,
-      indentationWidth: indentationWidth
-    )
-
-    assertMacroExpansion(
-      """
-      @AddSendable
-      extension A.B {
-      }
-      """,
-      expandedSource: """
-
-        extension A.B {
-        }
-
-        extension A.B: Sendable {
-        }
-        """,
-      macros: testMacros,
-      indentationWidth: indentationWidth
-    )
-  }
-
   func testExtensionExpansion() {
     assertMacroExpansion(
       """