From 67e88f4f26c20c2d7e4f339dbfe2a5891743d3e4 Mon Sep 17 00:00:00 2001
From: Rintaro Ishizaki <rishizaki@apple.com>
Date: Tue, 9 Jun 2020 12:21:56 -0700
Subject: [PATCH] [SourceKit] Disable labeled trailing closure support except
 code completion

Don't insert CodeCompletionExpr at the cursor position in
"conforming method list" or "typecontext" mode. This increase the chance
of successful type checking.

rdar://problem/63781922
---
 include/swift/Parse/CodeCompletionCallbacks.h |  4 +++
 lib/IDE/CodeCompletion.cpp                    |  4 +++
 lib/Parse/ParseExpr.cpp                       |  7 +++++
 .../IDE/conforming-methods-afterclosure.swift | 27 +++++++++++++++++++
 4 files changed, 42 insertions(+)
 create mode 100644 test/IDE/conforming-methods-afterclosure.swift

diff --git a/include/swift/Parse/CodeCompletionCallbacks.h b/include/swift/Parse/CodeCompletionCallbacks.h
index b8c5fe151fe83..eeee748a4b904 100644
--- a/include/swift/Parse/CodeCompletionCallbacks.h
+++ b/include/swift/Parse/CodeCompletionCallbacks.h
@@ -198,6 +198,10 @@ class CodeCompletionCallbacks {
 
   virtual void completeCallArg(CodeCompletionExpr *E, bool isFirst) {};
 
+  virtual bool canPerformCompleteLabeledTrailingClosure() const {
+    return false;
+  }
+
   virtual void completeLabeledTrailingClosure(CodeCompletionExpr *E,
                                               bool isAtStartOfLine) {};
 
diff --git a/lib/IDE/CodeCompletion.cpp b/lib/IDE/CodeCompletion.cpp
index f05c3c8ffe83a..99a42527e03ba 100644
--- a/lib/IDE/CodeCompletion.cpp
+++ b/lib/IDE/CodeCompletion.cpp
@@ -1687,6 +1687,10 @@ class CodeCompletionCallbacksImpl : public CodeCompletionCallbacks {
   void completeLabeledTrailingClosure(CodeCompletionExpr *E,
                                       bool isAtStartOfLine) override;
 
+  bool canPerformCompleteLabeledTrailingClosure() const override {
+    return true;
+  }
+
   void completeReturnStmt(CodeCompletionExpr *E) override;
   void completeYieldStmt(CodeCompletionExpr *E,
                          Optional<unsigned> yieldIndex) override;
diff --git a/lib/Parse/ParseExpr.cpp b/lib/Parse/ParseExpr.cpp
index 3922c9e2d1569..d35321bbced2e 100644
--- a/lib/Parse/ParseExpr.cpp
+++ b/lib/Parse/ParseExpr.cpp
@@ -3213,6 +3213,13 @@ Parser::parseTrailingClosures(bool isExprBasic, SourceRange calleeRange,
       if (!Tok.is(tok::code_complete))
         break;
 
+      // If the current completion mode doesn't support trailing closure
+      // completion, leave the token here and let "postfix completion" to
+      // handle it.
+      if (CodeCompletion &&
+          !CodeCompletion->canPerformCompleteLabeledTrailingClosure())
+        break;
+
       // foo() {} <token>
       auto CCExpr = new (Context) CodeCompletionExpr(Tok.getLoc());
       if (CodeCompletion)
diff --git a/test/IDE/conforming-methods-afterclosure.swift b/test/IDE/conforming-methods-afterclosure.swift
new file mode 100644
index 0000000000000..faa168b12761d
--- /dev/null
+++ b/test/IDE/conforming-methods-afterclosure.swift
@@ -0,0 +1,27 @@
+// RUN: %target-swift-ide-test -conforming-methods -source-filename %s -code-completion-token=AFTER_TRAILINGCLOSURE -module-name MyModule -conforming-methods-expected-types 's:8MyModule7TargetPP' | %FileCheck %s -check-prefix=AFTER_TRAILINGCLOSURE
+
+public protocol TargetP {}
+struct ConcreteP: TargetP {}
+
+public struct MyStruct {
+    init(arg1: Int = 0, fn: () -> Int) {}
+
+    public func returnSomeP -> some TargetP { ConcreteP() }
+    public func returnConcreteP -> ConcreteP { ConcreteP() }
+    public func reutrnInt -> Int { 1 }
+}
+
+func test() {
+    MyStruct {
+        1
+    } #^AFTER_TRAILINGCLOSURE^#
+}
+
+//AFTER_TRAILINGCLOSURE:      -----BEGIN CONFORMING METHOD LIST-----
+//AFTER_TRAILINGCLOSURE-NEXT: - TypeName: MyStruct
+//AFTER_TRAILINGCLOSURE-NEXT: - Members:
+//AFTER_TRAILINGCLOSURE-NEXT:    - Name: returnSomeP()
+//AFTER_TRAILINGCLOSURE-NEXT:      TypeName: some TargetP
+//AFTER_TRAILINGCLOSURE-NEXT:    - Name: returnConcreteP()
+//AFTER_TRAILINGCLOSURE-NEXT:      TypeName: ConcreteP
+//AFTER_TRAILINGCLOSURE-NEXT: -----END CONFORMING METHOD LIST-----