Add trailing comma support in cases missing from Swift 6.1

Author: calda

Sources/SwiftParser/Attributes.swift

@@ -362,7 +362,7 @@ extension Parser {
     let additionalArgs = self.parseArgumentListElements(
       pattern: .none,
       flavor: .attributeArguments,
-      allowTrailingComma: false
+      allowTrailingComma: true
     )
     return [roleElement] + additionalArgs
   }
@@ -852,6 +852,11 @@ extension Parser {
           arena: self.arena
         )
       )
+
+      // If this was a trailing closure then there are no more elements
+      if self.at(.rightParen) {
+        break
+      }
     } while keepGoing != nil
     return RawBackDeployedAttributeArgumentsSyntax(
       unexpectedBeforeLabel,
@@ -883,6 +888,11 @@ extension Parser {
           arena: self.arena
         )
       )
+
+      // If this was a trailing closure then there are no more elements
+      if self.at(.rightParen) {
+        break
+      }
     } while keepGoing != nil
 
     return RawOriginallyDefinedInAttributeArgumentsSyntax(
@@ -1001,6 +1011,11 @@ extension Parser {
           arena: self.arena
         )
       )
+
+      // If this was a trailing closure then there are no more elements
+      if self.at(.rightParen) {
+        break
+      }
     } while keepGoing != nil
 
     return RawDocumentationAttributeArgumentListSyntax(elements: arguments, arena: self.arena)

Sources/SwiftParser/Availability.swift

@@ -47,6 +47,11 @@ extension Parser {
             arena: self.arena
           )
         )
+
+        // If this was a trailing closure, there are no more elements
+        if self.at(.rightParen) {
+          break
+        }
       } while keepGoing != nil
         && self.hasProgressed(&availabilityArgumentProgress)
     }

Sources/SwiftParser/Nominals.swift

@@ -361,6 +361,11 @@ extension Parser {
             arena: self.arena
           )
         )
+
+        // If this was a trailing comma, there are no more elements
+        if at(prefix: ">") {
+          break
+        }
       } while keepGoing != nil && self.hasProgressed(&loopProgress)
     }
     let rangle = self.expectWithoutRecovery(prefix: ">", as: .rightAngle)

Sources/SwiftParser/Types.swift

@@ -430,6 +430,11 @@ extension Parser {
             arena: self.arena
           )
         )
+
+        // If this was a trailing comma, we're done parsing the list
+        if self.at(prefix: ">") {
+          break
+        }
       } while keepGoing != nil && self.hasProgressed(&loopProgress)
     }
 

Tests/SwiftParserTest/AttributeTests.swift

@@ -470,13 +470,31 @@ final class AttributeTests: ParserTestCase {
       """
     )
 
+    assertParse(
+      """
+      @backDeployed(
+        before: macOS 12.0,
+      )
+      struct Foo {}
+      """
+    )
+
     assertParse(
       """
       @backDeployed(before: macos 12.0, iOS 15.0)
       struct Foo {}
       """
     )
 
+    assertParse(
+      """
+      @backDeployed(
+        before: macos 12.0, 
+        iOS 15.0,)
+      struct Foo {}
+      """
+    )
+
     assertParse(
       """
       @available(macOS 11.0, *)
@@ -537,6 +555,16 @@ final class AttributeTests: ParserTestCase {
       """
     )
 
+    assertParse(
+      """
+      @_originallyDefinedIn(
+        module: "ToasterKit",
+        macOS 10.15,
+      )
+      struct Vehicle {}
+      """
+    )
+
     assertParse(
       """
       @_originallyDefinedIn(module: "ToasterKit", macOS 10.15, iOS 13)
@@ -846,6 +874,26 @@ final class AttributeTests: ParserTestCase {
         }
         """
     )
+
+    assertParse(
+      """
+      @attached(
+        member,
+        names: named(deinit),
+      )
+      macro m()
+      """
+    )
+
+    assertParse(
+      """
+      @attached(
+        extension,
+        conformances: P1, P2,
+      )
+      macro AddAllConformances()
+      """
+    )
   }
 
   func testAttachedExtensionAttribute() {

Tests/SwiftParserTest/DeclarationTests.swift

@@ -3529,4 +3529,31 @@ final class DeclarationTests: ParserTestCase {
       ]
     )
   }
+
+  func testTrailingCommas() {
+    assertParse(
+      """
+      protocol Baaz<
+        Foo,
+        Bar,
+      > {
+        associatedtype Foo
+        associatedtype Bar
+      }
+      """
+    )
+
+    assertParse(
+      """
+      struct Foo<
+        T1,
+        T2,
+        T3,
+      >: Baaz<
+        T1,
+        T2,
+      > {}
+      """
+    )
+  }
 }

Tests/SwiftParserTest/TypeTests.swift

@@ -734,6 +734,44 @@ final class TypeTests: ParserTestCase {
       fixedSource: "func foo(test: nonisolated(nonsendinghello) () async -> Void)"
     )
   }
+
+  func testTrailingCommas() {
+    assertParse(
+      """
+      let foo: (
+        bar: String,
+        quux: String,
+      )
+      """
+    )
+
+    assertParse(
+      """
+      let closure: (
+        String,
+        String,
+      ) -> (
+        bar: String,
+        quux: String,
+      )
+      """
+    )
+
+    assertParse(
+      """
+      struct Foo<T1, T2, T3,> {}
+
+      typealias Bar<
+        T1,
+        T2,
+      > = Foo<
+        T1,
+        T2,
+        Bool,
+      >
+      """
+    )
+  }
 }
 
 final class InlineArrayTypeTests: ParserTestCase {

Tests/SwiftParserTest/translated/AvailabilityQueryTests.swift

@@ -400,17 +400,7 @@ final class AvailabilityQueryTests: ParserTestCase {
       """
       if #available(OSX 10.51,1️⃣) {
       }
-      """,
-      diagnostics: [
-        DiagnosticSpec(
-          message: "expected version restriction in availability argument",
-          fixIts: ["insert version restriction"]
-        )
-      ],
-      fixedSource: """
-        if #available(OSX 10.51, <#identifier#>) {
-        }
-        """
+      """
     )
   }
 

Tests/SwiftParserTest/translated/AvailabilityQueryUnavailabilityTests.swift

@@ -381,19 +381,9 @@ final class AvailabilityQueryUnavailabilityTests: ParserTestCase {
   func testAvailabilityQueryUnavailability23() {
     assertParse(
       """
-      if #unavailable(OSX 10.51,1️⃣) {
+      if #unavailable(OSX 10.51,) {
       }
-      """,
-      diagnostics: [
-        DiagnosticSpec(
-          message: "expected version restriction in availability argument",
-          fixIts: ["insert version restriction"]
-        )
-      ],
-      fixedSource: """
-        if #unavailable(OSX 10.51, <#identifier#>) {
-        }
-        """
+      """
     )
   }
 
@@ -611,4 +601,18 @@ final class AvailabilityQueryUnavailabilityTests: ParserTestCase {
       ]
     )
   }
+
+  func testTrailingComma() {
+    assertParse(
+      """
+      func fooDeprecated() {
+        if #available(
+          iOS 18.0,
+          macOS 14.0,
+          *,
+        ) {}
+      }
+      """
+    )
+  }
 }