Suppress diagnostic in the case where there is no leading underscore, which triggers other diagnostics

Author: erichkeane

clang/lib/Basic/IdentifierTable.cpp

@@ -406,6 +406,9 @@ ReservedLiteralSuffixIdStatus
 IdentifierInfo::isReservedLiteralSuffixId() const {
   StringRef Name = getName();
 
+  // Note: the diag::warn_deprecated_literal_operator_id diagnostic depends on
+  // this being the first check we do, so if this order changes, we have to fix
+  // that as well.
   if (Name[0] != '_')
     return ReservedLiteralSuffixIdStatus::NotStartsWithUnderscore;
 

clang/lib/Sema/SemaExprCXX.cpp

@@ -508,7 +508,14 @@ bool Sema::checkLiteralOperatorId(const CXXScopeSpec &SS,
         Name.getSourceRange(),
         (StringRef("operator\"\"") + II->getName()).str());
 
-    Diag(Loc, diag::warn_deprecated_literal_operator_id) << II << Hint;
+    // Only emit this diagnostic if we start with an underscore, else the
+    // diagnostic for C++11 requiring a space between the quotes and the
+    // identifier conflicts with this and gets confusing. The diagnostic stating
+    // this is a reserved name should force the underscore, which gets this
+    // back.
+    if (II->isReservedLiteralSuffixId() !=
+        ReservedLiteralSuffixIdStatus::NotStartsWithUnderscore)
+      Diag(Loc, diag::warn_deprecated_literal_operator_id) << II << Hint;
 
     if (isReservedInAllContexts(Status))
       Diag(Loc, diag::warn_reserved_extern_symbol)

clang/test/CXX/drs/cwg17xx.cpp

@@ -203,9 +203,6 @@ namespace cwg1762 { // cwg1762: 14
   float operator ""E(const char *);
   // since-cxx11-error@-1 {{invalid suffix on literal; C++11 requires a space between literal and identifier}}
   // since-cxx11-warning@-2 {{user-defined literal suffixes not starting with '_' are reserved; no literal will invoke this operator}}
-  // since-cxx11-warning@-3 {{identifier 'E' preceded by whitespace in a literal operator declaration is deprecated}}
-  // FIXME: We could probably do a better job reacting to the fixit here, the
-  // fact that we complain about the space we added is a little strange.
 #endif
 }
 

clang/test/CXX/over/over.oper/over.literal/p8.cpp

@@ -8,10 +8,10 @@ namespace std {
 void operator ""_km(long double); // ok
 string operator ""_i18n(const char*, std::size_t); // ok
 template<char...> int operator ""\u03C0(); // ok, UCN for lowercase pi // expected-warning {{reserved}}
-float operator ""E(const char *); // expected-error {{invalid suffix on literal}} expected-warning {{reserved}} expected-warning{{whitespace}}
-float operator " " B(const char *); // expected-error {{must be '""'}} expected-warning {{reserved}} expected-warning{{whitespace}}
+float operator ""E(const char *); // expected-error {{invalid suffix on literal}} expected-warning {{reserved}}
+float operator " " B(const char *); // expected-error {{must be '""'}} expected-warning {{reserved}}
 string operator ""5X(const char *, std::size_t); // expected-error {{expected identifier}}
 double operator ""_miles(double); // expected-error {{parameter}}
-template<char...> int operator "" j(const char*); // expected-error {{template}} expected-warning{{whitespace}}
+template<char...> int operator "" j(const char*); // expected-error {{template}}
 
 float operator ""_E(const char *);

clang/test/Parser/cxx0x-literal-operators.cpp

@@ -3,8 +3,6 @@
 void operator "" (const char *); // expected-error {{expected identifier}}
 void operator "k" foo(const char *); // \
   expected-error {{string literal after 'operator' must be '""'}} \
-  expected-warning{{user-defined literal suffixes not starting with '_' are reserved}} \
-  expected-warning{{identifier 'foo' preceded by whitespace in a literal operator declaration is deprecated}}
+  expected-warning{{user-defined literal suffixes not starting with '_' are reserved}}
 void operator "" tester (const char *); // \
-  expected-warning{{user-defined literal suffixes not starting with '_' are reserved}} \
-  expected-warning{{identifier 'tester' preceded by whitespace in a literal operator declaration is deprecated}}
+  expected-warning{{user-defined literal suffixes not starting with '_' are reserved}}

clang/test/SemaCXX/no-warn-user-defined-literals-in-system-headers.cpp

@@ -3,4 +3,3 @@
 #include <no-warn-user-defined-literals-in-system-headers.h>
 
 void operator "" bar(long double); // expected-warning{{user-defined literal suffixes not starting with '_' are reserved}}
-// expected-warning@-1{{identifier 'bar' preceded by whitespace in a literal operator declaration is deprecated}}