nfc: introduce TypeBase::isCopyable

The days of double-negative conditions is over.

Author: kavon

include/swift/AST/Types.h

@@ -699,6 +699,9 @@ class alignas(1 << TypeAlignInBits) TypeBase
   /// Copyable.
   bool isNoncopyable();
 
+  /// Returns true if this contextual type satisfies a conformance to Copyable.
+  bool isCopyable();
+
   /// Returns true if this contextual type satisfies a conformance to Escapable.
   bool isEscapable();
 

lib/AST/ConformanceLookup.cpp

@@ -946,6 +946,11 @@ bool TypeBase::isNoncopyable() {
   return !Bits.TypeBase.IsCopyable;
 }
 
+/// \returns true iff this type conforms to Copyable.
+bool TypeBase::isCopyable() {
+  return !isNoncopyable();
+}
+
 /// \returns true iff this type conforms to Escaping.
 bool TypeBase::isEscapable() {
   if (!Bits.TypeBase.ComputedInvertibleConformances)