From ef4ece75fdb48b06ab4b8cd087a6fc64b44d5978 Mon Sep 17 00:00:00 2001
From: Ilya Biryukov <ibiryukov@google.com>
Date: Wed, 25 Apr 2018 15:13:34 +0000
Subject: [PATCH] [CodeComplete] Fix completion in the middle of ident in ctor
 lists.

Summary:
The example that was broken before (^ designates completion points):

    class Foo {
      Foo() : fie^ld^() {} // no completions were provided here.
      int field;
    };

To fix it we don't cut off lexing after an identifier followed by code
completion token is lexed. Instead we skip the rest of identifier and
continue lexing.
This is consistent with behavior of completion when completion token is
right before the identifier.

Reviewers: sammccall, aaron.ballman, bkramer, sepavloff, arphaman, rsmith

Reviewed By: aaron.ballman

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D44932

llvm-svn: 330833
---
 clang/lib/Lex/Lexer.cpp                        | 16 +++++++++++++++-
 clang/test/CodeCompletion/ctor-initializer.cpp |  4 ++++
 clang/test/CodeCompletion/end-of-file.cpp      |  7 +++++++
 3 files changed, 26 insertions(+), 1 deletion(-)
 create mode 100644 clang/test/CodeCompletion/end-of-file.cpp

diff --git a/clang/lib/Lex/Lexer.cpp b/clang/lib/Lex/Lexer.cpp
index ecb7c87..9179650 100644
--- a/clang/lib/Lex/Lexer.cpp
+++ b/clang/lib/Lex/Lexer.cpp
@@ -1654,7 +1654,21 @@ FinishIdentifier:
     if (isCodeCompletionPoint(CurPtr)) {
       // Return the code-completion token.
       Result.setKind(tok::code_completion);
-      cutOffLexing();
+      // Skip the code-completion char and all immediate identifier characters.
+      // This ensures we get consistent behavior when completing at any point in
+      // an identifier (i.e. at the start, in the middle, at the end). Note that
+      // only simple cases (i.e. [a-zA-Z0-9_]) are supported to keep the code
+      // simpler.
+      assert(*CurPtr == 0 && "Completion character must be 0");
+      ++CurPtr;
+      // Note that code completion token is not added as a separate character
+      // when the completion point is at the end of the buffer. Therefore, we need
+      // to check if the buffer has ended.
+      if (CurPtr < BufferEnd) {
+        while (isIdentifierBody(*CurPtr))
+          ++CurPtr;
+      }
+      BufferPtr = CurPtr;
       return true;
     }
 
diff --git a/clang/test/CodeCompletion/ctor-initializer.cpp b/clang/test/CodeCompletion/ctor-initializer.cpp
index e54b347..e1a0d14 100644
--- a/clang/test/CodeCompletion/ctor-initializer.cpp
+++ b/clang/test/CodeCompletion/ctor-initializer.cpp
@@ -58,5 +58,9 @@ struct B {
   // RUN: %clang_cc1 -fsyntax-only -std=c++98 -code-completion-at=%s:57:9 %s -o - | FileCheck -check-prefix=CHECK-CC7 %s
   // RUN: %clang_cc1 -fsyntax-only -std=c++14 -code-completion-at=%s:57:9 %s -o - | FileCheck -check-prefix=CHECK-CC7 %s
   // CHECK-CC7: COMPLETION: Pattern : member1(<#args#>
+  // Check in the middle and at the end of identifier too.
+  // RUN: %clang_cc1 -fsyntax-only -std=c++98 -code-completion-at=%s:57:13 %s -o - | FileCheck -check-prefix=CHECK-CC8 %s
+  // RUN: %clang_cc1 -fsyntax-only -std=c++98 -code-completion-at=%s:57:16 %s -o - | FileCheck -check-prefix=CHECK-CC8 %s
+  // CHECK-CC8: COMPLETION: Pattern : member2(<#args#>
   int member1, member2;
 };
diff --git a/clang/test/CodeCompletion/end-of-file.cpp b/clang/test/CodeCompletion/end-of-file.cpp
new file mode 100644
index 0000000..178ef45
--- /dev/null
+++ b/clang/test/CodeCompletion/end-of-file.cpp
@@ -0,0 +1,7 @@
+// Check that clang does not crash when completing at the last char in the
+// buffer.
+// NOTE: This file must *NOT* have newline at the end.
+// RUN: %clang_cc1 -code-completion-at=%s:7:2 %s | FileCheck %s
+// CHECK: COMPLETION: foo
+using foo = int***;
+f
\ No newline at end of file
-- 
2.7.4