Fix parsing error if @objc selector contains an underscore

Author: ahoppen

Sources/SwiftParser/Attributes.swift

@@ -494,7 +494,7 @@ extension Parser {
   mutating func parseObjectiveCSelector() -> RawObjCSelectorSyntax {
     var elements = [RawObjCSelectorPieceSyntax]()
     var loopProgress = LoopProgressCondition()
-    while !self.at(any: [.eof, .rightParen]) && loopProgress.evaluate(currentToken) {
+    while loopProgress.evaluate(currentToken) {
       // Empty selector piece.
       if let colon = self.consume(if: .colon) {
         elements.append(
@@ -507,7 +507,7 @@ extension Parser {
         continue
       }
 
-      if self.at(.identifier) || self.currentToken.isKeyword {
+      if self.at(any: [.identifier, .wildcardKeyword]) || self.currentToken.isKeyword {
         let name = self.consumeAnyToken()
 
         // If we hit a ')' we may have a zero-argument selector.
@@ -531,6 +531,8 @@ extension Parser {
             arena: self.arena
           )
         )
+      } else {
+        break
       }
     }
     return RawObjCSelectorSyntax(elements: elements, arena: self.arena)

Tests/SwiftParserTest/AttributeTests.swift

@@ -90,6 +90,13 @@ final class AttributeTests: XCTestCase {
       func f(_: Int, _: Int, _: Int, _: Int, _: Int) { }
       """
     )
+
+    AssertParse(
+      """
+      @objc(_:)
+      func f(_: Int)
+      """
+    )
   }
 
   func testRethrowsAttribute() {