Add leading space for in keyword

Author: kimdv

CodeGeneration/Sources/SyntaxSupport/gyb_generated/TokenSpec.swift

@@ -230,7 +230,7 @@ public let SYNTAX_TOKENS: [TokenSpec] = [
   StmtKeywordSpec(name: "Repeat", text: "repeat", requiresTrailingSpace: true),
   StmtKeywordSpec(name: "Else", text: "else", requiresTrailingSpace: true),
   StmtKeywordSpec(name: "For", text: "for", requiresTrailingSpace: true),
-  StmtKeywordSpec(name: "In", text: "in", requiresTrailingSpace: true),
+  StmtKeywordSpec(name: "In", text: "in", requiresLeadingSpace: true, requiresTrailingSpace: true),
   StmtKeywordSpec(name: "While", text: "while", requiresTrailingSpace: true),
   StmtKeywordSpec(name: "Return", text: "return", requiresTrailingSpace: true),
   StmtKeywordSpec(name: "Break", text: "break", requiresTrailingSpace: true),

Sources/SwiftBasicFormat/generated/BasicFormat.swift

@@ -125,6 +125,8 @@ open class BasicFormat: SyntaxRewriter {
 
   open func requiresLeadingSpace(_ token: TokenSyntax) -> Bool {
     switch token.tokenKind {
+    case .inKeyword: 
+      return true
     case .whereKeyword: 
       return true
     case .catchKeyword: 

Sources/SwiftSyntax/gyb_generated/SyntaxFactory.swift

@@ -8997,7 +8997,7 @@ public enum SyntaxFactory {
   }
   @available(*, deprecated, message: "Use TokenSyntax.inKeywordKeyword instead")
   public static func makeInKeyword(
-    leadingTrivia: Trivia = [],
+    leadingTrivia: Trivia = .space,
     trailingTrivia: Trivia = .space
   ) -> TokenSyntax {
     return makeToken(.inKeyword, presence: .present,

Tests/SwiftSyntaxBuilderTest/ClosureExprTests.swift

@@ -0,0 +1,37 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2022 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import XCTest
+import SwiftSyntax
+import SwiftSyntaxBuilder
+
+final class ClosureExprTests: XCTestCase {
+  func testClosureExpr() {
+    let buildable = ClosureExpr(
+      signature: ClosureSignature(
+        input: .simpleInput(
+          ClosureParamList {
+            ClosureParamSyntax(name: .identifier("area"))
+          }
+        )
+      )
+    ) {}
+
+    AssertBuildResult(
+      buildable,
+      """
+      {area in
+      }
+      """
+    )
+  }
+}

gyb_syntax_support/Token.py

@@ -216,7 +216,7 @@ def macro_name(self):
     StmtKeyword('Repeat', 'repeat'),
     StmtKeyword('Else', 'else'),
     StmtKeyword('For', 'for'),
-    StmtKeyword('In', 'in'),
+    StmtKeyword('In', 'in', requires_leading_space=True),
     StmtKeyword('While', 'while'),
     StmtKeyword('Return', 'return'),
     StmtKeyword('Break', 'break'),