From df0c350cce2e3c4f2b427a6ecf0d3ce8578031bf Mon Sep 17 00:00:00 2001
From: Rintaro Ishizaki <fs.output@gmail.com>
Date: Wed, 26 Oct 2016 21:30:08 +0900
Subject: [PATCH 1/2] [Parse] Eliminate unneeded backtracking scope in parsing
 .dynamicType

---
 lib/Parse/ParseExpr.cpp | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/lib/Parse/ParseExpr.cpp b/lib/Parse/ParseExpr.cpp
index 583943fc827bd..2935dc245476d 100644
--- a/lib/Parse/ParseExpr.cpp
+++ b/lib/Parse/ParseExpr.cpp
@@ -1453,9 +1453,8 @@ ParserResult<Expr> Parser::parseExprPostfix(Diag<> ID, bool isExprBasic) {
 
       // Handle the deprecated 'x.dynamicType' and migrate it to `type(of: x)`
       if (Tok.getText() == "dynamicType") {
-        BacktrackingScope backtrackScope(*this);
         auto range = Result.get()->getSourceRange();
-        auto dynamicTypeExprRange = SourceRange(TokLoc, consumeToken());
+        auto dynamicTypeExprRange = SourceRange(TokLoc, Tok.getLoc());
         diagnose(TokLoc, diag::expr_dynamictype_deprecated)
           .highlight(dynamicTypeExprRange)
           .fixItReplace(dynamicTypeExprRange, ")")

From 47e07bc6112b4e04dce7687781f5af5d2bdbc914 Mon Sep 17 00:00:00 2001
From: Rintaro Ishizaki <fs.output@gmail.com>
Date: Wed, 26 Oct 2016 21:41:23 +0900
Subject: [PATCH 2/2] [Parse] Create DiagnosticTransaction along with
 BacktrackingScope

This prevents duplicated diagnostics.
---
 include/swift/Parse/Parser.h             | 13 ++++++++++---
 test/expr/primary/unqualified_name.swift | 11 +++++++++++
 2 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/include/swift/Parse/Parser.h b/include/swift/Parse/Parser.h
index dae83a212f7e8..57243d3f37b17 100644
--- a/include/swift/Parse/Parser.h
+++ b/include/swift/Parse/Parser.h
@@ -350,17 +350,24 @@ class Parser {
   class BacktrackingScope {
     Parser &P;
     ParserPosition PP;
+    DiagnosticTransaction DT;
     bool Backtrack = true;
 
   public:
-    BacktrackingScope(Parser &P) : P(P), PP(P.getParserPosition()) {}
+    BacktrackingScope(Parser &P)
+      : P(P), PP(P.getParserPosition()), DT(P.Diags) {}
 
     ~BacktrackingScope() {
-      if (Backtrack)
+      if (Backtrack) {
         P.backtrackToPosition(PP);
+        DT.abort();
+      }
     }
 
-    void cancelBacktrack() { Backtrack = false; }
+    void cancelBacktrack() {
+      Backtrack = false;
+      DT.commit();
+    }
   };
 
   /// RAII object that, when it is destructed, restores the parser and lexer to
diff --git a/test/expr/primary/unqualified_name.swift b/test/expr/primary/unqualified_name.swift
index 82d9f9b7baf46..8d222f5f821fa 100644
--- a/test/expr/primary/unqualified_name.swift
+++ b/test/expr/primary/unqualified_name.swift
@@ -73,3 +73,14 @@ class C1 : C0 {
   }
 }
 
+struct S1 {
+  init(x: Int) {} // expected-note {{'init(x:)' declared here}}
+
+  func testS1() {
+    _ = S1.init(x:)(1)
+    _ = S1.init(`x`: 1)  // expected-warning {{keyword 'x' does not need to be escaped in argument list}} {{17-18=}} {{19-20=}}
+
+    // Test for unknown token.
+    _ = S1.init(x: 0xG) // expected-error {{expected a digit after integer literal prefix}} expected-error {{missing argument for parameter 'x' in call}}
+  }
+}