From d58ca9343979c4a9b36fec0f4bb6cf429c541fc2 Mon Sep 17 00:00:00 2001
From: Rintaro Ishizaki <rishizaki@apple.com>
Date: Fri, 12 May 2023 09:52:32 -0700
Subject: [PATCH] [Macros] Don't fold operators in unnecessary nodes

For attached macros, operator folding should only be done for the
attribute syntax node, but not for the target declaration syntax and
the parent decl syntax. This aligns with the compiler's ASTGen.
---
 Sources/SwiftCompilerPluginMessageHandling/Macros.swift  | 8 ++++++--
 .../PluginMacroExpansionContext.swift                    | 9 +++++++--
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/Sources/SwiftCompilerPluginMessageHandling/Macros.swift b/Sources/SwiftCompilerPluginMessageHandling/Macros.swift
index ab0859b4fcd..389c6b678ba 100644
--- a/Sources/SwiftCompilerPluginMessageHandling/Macros.swift
+++ b/Sources/SwiftCompilerPluginMessageHandling/Macros.swift
@@ -12,6 +12,7 @@
 
 import SwiftBasicFormat
 import SwiftDiagnostics
+import SwiftOperators
 import SwiftSyntax
 import SwiftSyntaxMacros
 
@@ -28,7 +29,7 @@ extension CompilerPluginMessageHandler {
     expandingSyntax: PluginMessage.Syntax
   ) throws {
     let sourceManager = SourceManager()
-    let syntax = sourceManager.add(expandingSyntax)
+    let syntax = sourceManager.add(expandingSyntax, foldingWith: .standardOperators)
 
     let context = PluginMacroExpansionContext(
       sourceManager: sourceManager,
@@ -97,7 +98,10 @@ extension CompilerPluginMessageHandler {
       expansionDiscriminator: discriminator
     )
 
-    let attributeNode = sourceManager.add(attributeSyntax).cast(AttributeSyntax.self)
+    let attributeNode = sourceManager.add(
+      attributeSyntax,
+      foldingWith: .standardOperators
+    ).cast(AttributeSyntax.self)
     let declarationNode = sourceManager.add(declSyntax).cast(DeclSyntax.self)
 
     let expandedSources: [String]
diff --git a/Sources/SwiftCompilerPluginMessageHandling/PluginMacroExpansionContext.swift b/Sources/SwiftCompilerPluginMessageHandling/PluginMacroExpansionContext.swift
index 4f225f82d13..a554fe5a949 100644
--- a/Sources/SwiftCompilerPluginMessageHandling/PluginMacroExpansionContext.swift
+++ b/Sources/SwiftCompilerPluginMessageHandling/PluginMacroExpansionContext.swift
@@ -64,7 +64,10 @@ class SourceManager {
 
   /// Convert syntax information to a `Syntax` node. The location informations
   /// are cached in the source manager to provide `location(of:)` et al.
-  func add(_ syntaxInfo: PluginMessage.Syntax) -> Syntax {
+  func add(
+    _ syntaxInfo: PluginMessage.Syntax,
+    foldingWith operatorTable: OperatorTable? = nil
+  ) -> Syntax {
 
     var node: Syntax
     var parser = Parser(syntaxInfo.source)
@@ -82,7 +85,9 @@ class SourceManager {
     case .attribute:
       node = Syntax(AttributeSyntax.parse(from: &parser))
     }
-    node = OperatorTable.standardOperators.foldAll(node, errorHandler: { _ in /*ignore*/ })
+    if let operatorTable = operatorTable {
+      node = operatorTable.foldAll(node, errorHandler: { _ in /*ignore*/ })
+    }
 
     // Copy the location info from the plugin message.
     let location = KnownSourceSyntax.Location(