[Clang][Lex] Warn on trailing whitespace in #include filenames

Author: vandana11054

clang/include/clang/Basic/DiagnosticGroups.td

@@ -532,7 +532,7 @@ def Dangling : DiagGroup<"dangling", [DanglingAssignment,
                                       DanglingInitializerList,
                                       DanglingGsl,
                                       ReturnStackAddress]>;
-
+def G_TrailingSpaceInInclude : DiagGroup<"trailing-space-in-include">;
 def LifetimeSafetyPermissive : DiagGroup<"experimental-lifetime-safety-permissive">;
 def LifetimeSafetyStrict : DiagGroup<"experimental-lifetime-safety-strict">;
 def LifetimeSafety : DiagGroup<"experimental-lifetime-safety",

clang/include/clang/Basic/DiagnosticLexKinds.td

@@ -495,6 +495,8 @@ def err_vaopt_paste_at_start : Error<
 def err_vaopt_paste_at_end
     : Error<"'##' cannot appear at end of __VA_OPT__ argument">;
 
+def warn_trailing_space_in_include : Warning< "trailing space in #include file name" >,
+InGroup<G_TrailingSpaceInInclude>;
 def ext_pp_macro_redef : ExtWarn<"%0 macro redefined">, InGroup<MacroRedefined>;
 def ext_variadic_macro : Extension<"variadic macros are a C99 feature">,
   InGroup<VariadicMacros>;