prevent move-only tuples from matching with Any

`Any`, which is effectively `any _Copyable`, is obviously copyable.

Author: kavon

include/swift/AST/Types.h

@@ -602,9 +602,8 @@ class alignas(1 << TypeAlignInBits) TypeBase
 
   bool isPlaceholder();
 
-  /// Returns true if this is a move only type. Returns false if this is a
-  /// non-move only type or a move only wrapped type.
-  bool isPureMoveOnly() const;
+  /// Returns true if this is a move-only type.
+  bool isPureMoveOnly();
 
   /// Does the type have outer parenthesis?
   bool hasParenSugar() const { return getKind() == TypeKind::Paren; }

lib/AST/Type.cpp

@@ -165,9 +165,17 @@ bool TypeBase::isAny() {
   return constraint->isEqual(getASTContext().TheAnyType);
 }
 
-bool TypeBase::isPureMoveOnly() const {
-  if (auto *nom = getCanonicalType()->getNominalOrBoundGenericNominal())
+bool TypeBase::isPureMoveOnly() {
+  if (auto *nom = getNominalOrBoundGenericNominal())
     return nom->isMoveOnly();
+
+  // if any components of the tuple are move-only, then the tuple is move-only.
+  if (auto *tupl = getCanonicalType()->getAs<TupleType>()) {
+    for (auto eltTy : tupl->getElementTypes())
+      if (eltTy->isPureMoveOnly())
+        return true;
+  }
+
   return false;
 }
 

test/Constraints/moveonly_constraints.swift

@@ -91,6 +91,9 @@ func testBasic(_ mo: MO) {
 
   let singleton : (MO) = (mo)
   takeGeneric(singleton) // expected-error {{move-only type 'MO' cannot be used with generics yet}}
+
+  takeAny((mo)) // expected-error {{move-only type 'MO' cannot be used with generics yet}}
+  takeAny((mo, mo)) // expected-error {{move-only type '(MO, MO)' cannot be used with generics yet}}
 }
 
 func checkBasicBoxes() {