From: Jordan Rose <jordan_rose@apple.com>
Date: Thu, 24 Jan 2013 20:50:52 +0000 (+0000)
Subject: Add a fixit for \U1234 -> \u1234.
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=b87672b124ab4fbe6f2cabc2ad71655fc71230ea;p=clang

Add a fixit for \U1234 -> \u1234.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@173371 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/include/clang/Basic/DiagnosticLexKinds.td b/include/clang/Basic/DiagnosticLexKinds.td
index 00b385ef12..e3bff51b8e 100644
--- a/include/clang/Basic/DiagnosticLexKinds.td
+++ b/include/clang/Basic/DiagnosticLexKinds.td
@@ -114,12 +114,13 @@ def err_ucn_escape_incomplete : Error<
 def warn_ucn_escape_incomplete : Warning<
   "incomplete universal character name; "
   "treating as '\\' followed by identifier">, InGroup<Unicode>;
-def err_ucn_escape_invalid : Error<"invalid universal character">;
+def note_ucn_four_not_eight : Note<"did you mean to use '\\u'?">;
 
 def err_ucn_escape_basic_scs : Error<
   "character '%0' cannot be specified by a universal character name">;
 def err_ucn_control_character : Error<
   "universal character name refers to a control character">;
+def err_ucn_escape_invalid : Error<"invalid universal character">;
 def warn_cxx98_compat_literal_ucn_escape_basic_scs : Warning<
   "specifying character '%0' with a universal character name "
   "is incompatible with C++98">, InGroup<CXX98Compat>, DefaultIgnore;
diff --git a/lib/Lex/Lexer.cpp b/lib/Lex/Lexer.cpp
index 2a57e6fced..a4d6a2e8f7 100644
--- a/lib/Lex/Lexer.cpp
+++ b/lib/Lex/Lexer.cpp
@@ -2725,8 +2725,16 @@ uint32_t Lexer::tryReadUCN(const char *&StartPtr, const char *SlashLoc,
           Diag(BufferPtr, diag::warn_ucn_escape_no_digits)
             << StringRef(KindLoc, 1);
         } else {
-          // FIXME: if i == 4 and NumHexDigits == 8, suggest a fixit to \u.
           Diag(BufferPtr, diag::warn_ucn_escape_incomplete);
+
+          // If the user wrote \U1234, suggest a fixit to \u.
+          if (i == 4 && NumHexDigits == 8) {
+            CharSourceRange URange =
+              CharSourceRange::getCharRange(getSourceLocation(KindLoc),
+                                            getSourceLocation(KindLoc + 1));
+            Diag(KindLoc, diag::note_ucn_four_not_eight)
+              << FixItHint::CreateReplacement(URange, "u");
+          }
         }
       }
       
diff --git a/test/Preprocessor/ucn-pp-identifier.c b/test/Preprocessor/ucn-pp-identifier.c
index f4afa91ed3..b6e46516d8 100644
--- a/test/Preprocessor/ucn-pp-identifier.c
+++ b/test/Preprocessor/ucn-pp-identifier.c
@@ -1,5 +1,6 @@
 // RUN: %clang_cc1 %s -fsyntax-only -std=c99 -pedantic -verify -Wundef
 // RUN: %clang_cc1 %s -fsyntax-only -x c++ -pedantic -verify -Wundef
+// RUN: %clang_cc1 %s -fsyntax-only -std=c99 -pedantic -fdiagnostics-parseable-fixits -Wundef 2>&1 | FileCheck -strict-whitespace %s
 
 #define \u00FC
 #define a\u00FD() 0
@@ -95,3 +96,11 @@ C 1
 #else
 #error "Line splicing failed to produce UCNs"
 #endif
+
+
+#define capital_u_\U00FC
+// expected-warning@-1 {{incomplete universal character name}} expected-note@-1 {{did you mean to use '\u'?}} expected-warning@-1 {{whitespace}}
+// CHECK: note: did you mean to use '\u'?
+// CHECK-NEXT:   #define capital_u_\U00FC
+// CHECK-NEXT: {{^                   \^}}
+// CHECK-NEXT: {{^                   u}}