diff --git a/clang/include/clang/Basic/Module.h b/clang/include/clang/Basic/Module.h
index 3d035f0a5f787..69a1de6f79b35 100644
--- a/clang/include/clang/Basic/Module.h
+++ b/clang/include/clang/Basic/Module.h
@@ -64,6 +64,11 @@ struct ASTFileSignature : std::array<uint8_t, 20> {
 
   explicit operator bool() const { return *this != BaseT({{0}}); }
 
+  // Support implicit cast to ArrayRef.  Note that ASTFileSignature::size
+  // prevents implicit cast to ArrayRef because one of the implicit constructors
+  // of ArrayRef requires access to BaseT::size.
+  operator ArrayRef<uint8_t>() const { return ArrayRef<uint8_t>(data(), size); }
+
   /// Returns the value truncated to the size of an uint64_t.
   uint64_t truncatedValue() const {
     uint64_t Value = 0;
diff --git a/llvm/include/llvm/ADT/ArrayRef.h b/llvm/include/llvm/ADT/ArrayRef.h
index 892482d64e4a1..268510b803ea0 100644
--- a/llvm/include/llvm/ADT/ArrayRef.h
+++ b/llvm/include/llvm/ADT/ArrayRef.h
@@ -98,11 +98,6 @@ namespace llvm {
     /*implicit*/ constexpr ArrayRef(const C &V)
         : Data(V.data()), Length(V.size()) {}
 
-    /// Construct an ArrayRef from a std::array
-    template <size_t N>
-    /*implicit*/ constexpr ArrayRef(const std::array<T, N> &Arr)
-        : Data(Arr.data()), Length(N) {}
-
     /// Construct an ArrayRef from a C array.
     template <size_t N>
     /*implicit*/ constexpr ArrayRef(const T (&Arr LLVM_LIFETIME_BOUND)[N])