---

yaml
---
r: 278510
b: refs/heads/swift-5.1-old-llvm-branch
c: 003850f
h: refs/heads/master

Author: jrose-apple

[refs]

@@ -1241,7 +1241,7 @@ refs/tags/swift-DEVELOPMENT-SNAPSHOT-2019-01-24-a: b6f62823aa5010b2ae53f15f72a57
 refs/heads/marcrasi-astverifier-disable: 3fac766a23a77ebd0640296bfd7fc116ea60a4e0
 refs/heads/revert-22227-a-tall-white-fountain-played: adfce60b2eaa54903ea189bed8a783bca609fa53
 refs/heads/revert-22300-revert-22227-a-tall-white-fountain-played: 5f92040224df7dd4e618fdfb367349df64d8acad
-refs/heads/swift-5.1-old-llvm-branch: 7b0d10e2c762c5e3d4fb1ca1bef969db8a1cc536
+refs/heads/swift-5.1-old-llvm-branch: 003850fb0d886493305f7f7a0b23dbadc2bbfd07
 refs/heads/swift-5.1-branch: 8060872acb4105d9655e020fe047e1ebcd77d0fb
 refs/tags/swift-4.2.2-RELEASE: e429d1f1aaf59e69d38207a96e56265c7f6fccec
 refs/tags/swift-5.0-DEVELOPMENT-SNAPSHOT-2019-02-02-a: 3e5a03d32ff3b1e9af90d6c1198c14f938379a6e

branches/swift-5.1-old-llvm-branch/lib/Parse/ParseStmt.cpp

@@ -92,6 +92,18 @@ bool Parser::isStartOfStmt() {
     // putting a label on something inappropriate in parseStmt().
     return isStartOfStmt();
   }
+
+  case tok::at_sign: {
+    // Might be a statement or case attribute. The only one of these we have
+    // right now is `@unknown default`, so hardcode a check for an attribute
+    // without any parens.
+    if (!peekToken().is(tok::identifier))
+      return false;
+    Parser::BacktrackingScope backtrack(*this);
+    consumeToken(tok::at_sign);
+    consumeToken(tok::identifier);
+    return isStartOfStmt();
+  }
   }
 }
 

branches/swift-5.1-old-llvm-branch/test/Parse/switch.swift

@@ -609,3 +609,38 @@ switch x {
 @unknown default: // expected-error {{additional 'case' blocks cannot appear after the 'default' block of a 'switch'}}
   break
 }
+
+func testReturnBeforeUnknownDefault() {
+  switch x { // expected-error {{switch must be exhaustive}}
+  case 1:
+    return
+  @unknown default: // expected-note {{remove '@unknown' to handle remaining values}}
+    break
+  }
+}
+
+func testReturnBeforeIncompleteUnknownDefault() {
+  switch x { // expected-error {{switch must be exhaustive}}
+  case 1:
+    return
+  @unknown default // expected-error {{expected ':' after 'default'}}
+  // expected-note@-1 {{remove '@unknown' to handle remaining values}}
+  }
+}
+
+func testReturnBeforeIncompleteUnknownDefault2() {
+  switch x { // expected-error {{switch must be exhaustive}} expected-note {{do you want to add a default clause?}}
+  case 1:
+    return
+  @unknown // expected-error {{unknown attribute 'unknown'}}
+  } // expected-error {{expected declaration}}
+}
+
+func testIncompleteArrayLiteral() {
+  switch x { // expected-error {{switch must be exhaustive}}
+  case 1:
+    _ = [1 // expected-error {{expected ']' in container literal expression}} expected-note {{to match this opening '['}}
+  @unknown default: // expected-note {{remove '@unknown' to handle remaining values}}
+    ()
+  }
+}