BasicFormat should add a space between '{' and identifier

Author: bnbarham

Sources/SwiftBasicFormat/BasicFormat.swift

@@ -197,7 +197,6 @@ open class BasicFormat: SyntaxRewriter {
       (.keyword(.set), .leftParen),  // var mYar: Int { set(value) {} }
       (.keyword(.subscript), .leftParen),  // subscript(x: Int)
       (.keyword(.super), .period),  // super.someProperty
-      (.leftBrace, _),
       (.leftParen, _),
       (.leftSquareBracket, _),
       (.multilineStringQuote, .rawStringDelimiter),  // closing raw string delimiter should never be separate by a space
@@ -246,6 +245,10 @@ open class BasicFormat: SyntaxRewriter {
       return false
     case (_, .rightAngle) where first?.tokenKind != .leftAngle:  // `<` and `>` need to be separated by a space because otherwise they become an operator
       return false
+    case (.leftBrace, .identifier):
+      break
+    case (.leftBrace, _):
+      return false
     default:
       break
     }

Tests/SwiftBasicFormatTest/BasicFormatTests.swift

@@ -327,4 +327,19 @@ final class BasicFormatTest: XCTestCase {
       using: BasicFormat(indentationWidth: .spaces(2))
     )
   }
+
+  func testClosureExprParam() {
+    let source = """
+      _ = {foo in
+      }
+      """
+
+    assertFormatted(
+      source: source,
+      expected: """
+        _ = { foo in
+        }
+        """
+    )
+  }
 }