Add diagnostic if #sourceLocation is followed by any declarations

Author: kimdv

Sources/SwiftParser/Directives.swift

@@ -163,16 +163,8 @@ extension Parser {
     }
 
     let (unexpectedBeforePoundEndIf, poundEndIf) = self.expect(.poundEndifKeyword)
-    var unexpectedAfterPoundEndif: RawUnexpectedNodesSyntax?
-    if !self.currentToken.isAtStartOfLine {
-      var unexpectedTokens = [RawTokenSyntax]()
-      var loopProgress = LoopProgressCondition()
-      while !self.at(.eof), !currentToken.isAtStartOfLine, loopProgress.evaluate(self.currentToken) {
-        unexpectedTokens += [self.consumeAnyToken()]
-      }
+    let unexpectedAfterPoundEndif = self.consumeRemainingTokenOnLine()
 
-      unexpectedAfterPoundEndif = RawUnexpectedNodesSyntax(unexpectedTokens, arena: self.arena)
-    }
     return RawIfConfigDeclSyntax(
       clauses: RawIfConfigClauseListSyntax(elements: clauses, arena: self.arena),
       unexpectedBeforePoundEndIf,
@@ -267,14 +259,33 @@ extension Parser {
       args = nil
     }
     let (unexpectedBeforeRParen, rparen) = self.expect(.rightParen)
+    let unexpectedAfterRightParen = self.consumeRemainingTokenOnLine()
+
     return RawPoundSourceLocationSyntax(
       poundSourceLocation: line,
       unexpectedBeforeLParen,
       leftParen: lparen,
       args: args,
       unexpectedBeforeRParen,
       rightParen: rparen,
+      unexpectedAfterRightParen,
       arena: self.arena
     )
   }
+
+  /// Consumes remaining token on the line and returns a ``RawUnexpectedNodesSyntax``
+  /// if there is any tokens conrumed.
+  private mutating func consumeRemainingTokenOnLine() -> RawUnexpectedNodesSyntax? {
+    guard !self.currentToken.isAtStartOfLine else {
+      return nil
+    }
+
+    var unexpectedTokens = [RawTokenSyntax]()
+    var loopProgress = LoopProgressCondition()
+    while !self.at(.eof), !currentToken.isAtStartOfLine, loopProgress.evaluate(self.currentToken) {
+      unexpectedTokens += [self.consumeAnyToken()]
+    }
+
+    return RawUnexpectedNodesSyntax(unexpectedTokens, arena: self.arena)
+  }
 }

Sources/SwiftParserDiagnostics/ParseDiagnosticsGenerator.swift

@@ -1424,6 +1424,22 @@ public class ParseDiagnosticsGenerator: SyntaxAnyVisitor {
     return .visitChildren
   }
 
+  public override func visit(_ node: PoundSourceLocationSyntax) -> SyntaxVisitorContinueKind {
+    if shouldSkip(node) {
+      return .skipChildren
+    }
+
+    if let unexpectedAfterRightParen = node.unexpectedAfterRightParen {
+      addDiagnostic(
+        unexpectedAfterRightParen,
+        .extraTokensAtTheEndOfSourceLocationDirective,
+        handledNodes: [unexpectedAfterRightParen.id]
+      )
+    }
+
+    return .visitChildren
+  }
+
   public override func visit(_ node: PrecedenceGroupAssignmentSyntax) -> SyntaxVisitorContinueKind {
     if shouldSkip(node) {
       return .skipChildren

Sources/SwiftParserDiagnostics/ParserDiagnosticMessages.swift

@@ -156,6 +156,9 @@ extension DiagnosticMessage where Self == StaticParserError {
   public static var expectedSequenceExpressionInForEachLoop: Self {
     .init("expected Sequence expression for for-each loop")
   }
+  public static var extraTokensAtTheEndOfSourceLocationDirective: Self {
+    .init("extra tokens at the end of #sourceLocation directive")
+  }
   public static var extraTokensFollowingConditionalCompilationDirective: Self {
     .init("extra tokens following conditional compilation directive")
   }

Tests/SwiftParserTest/DirectiveTests.swift

@@ -213,4 +213,25 @@ final class DirectiveTests: XCTestCase {
       ]
     )
   }
+
+  func testSourcelocationDirectiveFollowedByDeclarations() {
+    assertParse(
+      """
+      var sometName: Int
+      #sourceLocation(file: "other.swift", line: 1)
+      var someName: Int
+      """
+    )
+
+    assertParse(
+      """
+      #sourceLocation(file: "other.swift", line: 1)1️⃣; let x = 1
+      """,
+      diagnostics: [
+        DiagnosticSpec(
+          message: "extra tokens at the end of #sourceLocation directive"
+        )
+      ]
+    )
+  }
 }