Add release note for SwiftIfConfig

Author: DougGregor

Release Notes/601.md

@@ -15,6 +15,10 @@
   - Description: This method translates an error into one or more diagnostics, recognizing `DiagnosticsError` and `DiagnosticMessage` instances or providing its own `Diagnostic` as needed.
   - Pull Request: https://github.com/swiftlang/swift-syntax/pull/1816
 
+- Added a new library `SwiftIfConfig`.
+  - Description: This new library provides facilities for evaluating `#if` conditions and determining which regions of a syntax tree are active according to a given build configuration.
+  - Pull Request: https://github.com/swiftlang/swift-syntax/pull/1816
+
 ## API Behavior Changes
 
 - `SyntaxProtocol.trimmed` detaches the node

Sources/SwiftIfConfig/IfConfigEvaluation.swift

@@ -41,7 +41,8 @@ func evaluateIfConfig(
     return (
       active: false,
       versioned: true,
-      diagnostics: extraDiagnostics + error.asDiagnostics(at: node))
+      diagnostics: extraDiagnostics + error.asDiagnostics(at: node)
+    )
   }
 
   /// Record an if-config evaluation error before returning it. Use this for
@@ -133,9 +134,9 @@ func evaluateIfConfig(
       switch (lhsActive, op.operator.text) {
       case (true, "||"):
         return (active: true, versioned: lhsVersioned, diagnostics: lhsDiagnostics)
-      case (false, "&&"): 
+      case (false, "&&"):
         return (active: false, versioned: lhsVersioned, diagnostics: lhsDiagnostics)
-      default: 
+      default:
         break
       }
     }

Sources/SwiftIfConfig/SyntaxProtocol+IfConfig.swift

@@ -32,7 +32,7 @@ extension SyntaxProtocol {
   /// configuration options `DEBUG` and `B` are provided, but `A` is not.
   public func isActive(
     in configuration: some BuildConfiguration
-  ) -> (state: IfConfigRegionState, diagnostics: [Diagnostic])  {
+  ) -> (state: IfConfigRegionState, diagnostics: [Diagnostic]) {
     var currentNode: Syntax = Syntax(self)
     var currentState: IfConfigRegionState = .active
     var diagnostics: [Diagnostic] = []

Tests/SwiftIfConfigTest/EvaluateTests.swift

@@ -16,8 +16,8 @@ import SwiftParser
 import SwiftSyntax
 @_spi(XCTestFailureLocation) @_spi(Testing) import SwiftSyntaxMacrosGenericTestSupport
 import XCTest
-import _SwiftSyntaxTestSupport
 import _SwiftSyntaxGenericTestSupport
+import _SwiftSyntaxTestSupport
 
 public class EvaluateTests: XCTestCase {
   func testLiterals() throws {
@@ -245,7 +245,7 @@ func assertIfConfig(
   // Evaluate the condition to check the state.
   let actualDiagnostics: [Diagnostic]
   let actualState: IfConfigRegionState
-    (actualState, actualDiagnostics) = IfConfigRegionState.evaluating (condition, in: configuration)
+  (actualState, actualDiagnostics) = IfConfigRegionState.evaluating(condition, in: configuration)
   XCTAssertEqual(actualState, expectedState, file: file, line: line)
 
   // Check the diagnostics.

Tests/SwiftIfConfigTest/VisitorTests.swift

@@ -16,8 +16,8 @@ import SwiftParser
 import SwiftSyntax
 @_spi(XCTestFailureLocation) @_spi(Testing) import SwiftSyntaxMacrosGenericTestSupport
 import XCTest
-import _SwiftSyntaxTestSupport
 import _SwiftSyntaxGenericTestSupport
+import _SwiftSyntaxTestSupport
 
 /// Visitor that ensures that all of the nodes we visit are active.
 ///