diff --git a/include/clang/Sema/Sema.h b/include/clang/Sema/Sema.h
index 262c32ab9c7bddfa517486c72176f31a7dacbf92..f8252fd0d795c2da2e444e5428ab28ec3ea0f1ab 100644
--- a/include/clang/Sema/Sema.h
+++ b/include/clang/Sema/Sema.h
@@ -1555,7 +1555,7 @@ public:
   /// visible at the specified location.
   void makeMergedDefinitionVisible(NamedDecl *ND);
 
-  bool isModuleVisible(Module *M) { return VisibleModules.isVisible(M); }
+  bool isModuleVisible(const Module *M) { return VisibleModules.isVisible(M); }
 
   /// Determine whether a declaration is visible to name lookup.
   bool isVisible(const NamedDecl *D) {