When we hit a #include directive that maps to a module import, emit a token
representing the module import rather than making the module immediately
visible. This serves two goals:
 * It avoids making declarations in the module visible prematurely, if we
   walk past the #include during a tentative parse, for instance, and
 * It gives a diagnostic (although, admittedly, not a very nice one) if
   a header with a corresponding module is included anywhere other than
   at the top level.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@194782 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Frontend/PrintPreprocessedOutput.cpp b/lib/Frontend/PrintPreprocessedOutput.cpp
index 3545d70..55a66d8 100644
--- a/lib/Frontend/PrintPreprocessedOutput.cpp
+++ b/lib/Frontend/PrintPreprocessedOutput.cpp
@@ -657,6 +657,11 @@
       // -traditional-cpp the lexer keeps /all/ whitespace, including comments.
       SourceLocation StartLoc = Tok.getLocation();
       Callbacks->MoveToLine(StartLoc.getLocWithOffset(Tok.getLength()));
+    } else if (Tok.is(tok::annot_module_include)) {
+      // PrintPPOutputPPCallbacks::InclusionDirective handles producing
+      // appropriate output here. Ignore this token entirely.
+      PP.Lex(Tok);
+      continue;
     } else if (IdentifierInfo *II = Tok.getIdentifierInfo()) {
       OS << II->getName();
     } else if (Tok.isLiteral() && !Tok.needsCleaning() &&