3 files changed, 26 insertions, 1 deletions
diff --git a/clang/lib/Lex/Lexer.cpp b/clang/lib/Lex/Lexer.cpp
index ecb7c87a3c6..9179650187e 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 e54b347f9fa..e1a0d143687 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 00000000000..178ef4561f5
--- /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