Address other review feedback

Author: hamishknight

include/swift/AST/Attr.def

@@ -498,7 +498,7 @@ DECL_ATTR(_projectedValueProperty, ProjectedValueProperty,
   89)
 SIMPLE_DECL_ATTR(_nonEphemeral, NonEphemeral,
   OnParam | UserInaccessible |
-  ABIStableToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove,
+  ABIStableToAdd | ABIStableToRemove | APIBreakingToAdd | APIStableToRemove,
   90)
 
 SIMPLE_DECL_ATTR(IBSegueAction, IBSegueAction,

include/swift/AST/DiagnosticsSema.def

@@ -2796,7 +2796,7 @@ NOTE(escaping_optional_type_argument, none,
 
 // @_nonEphemeral attribute
 ERROR(non_ephemeral_non_pointer_type,none,
-      "@_nonEphemeral attribute currently only applies to pointer types", ())
+      "@_nonEphemeral attribute only applies to pointer types", ())
 
 // NSManaged attribute
 ERROR(attr_NSManaged_not_instance_member,none,

lib/Sema/CSFix.cpp

@@ -1026,8 +1026,8 @@ TreatEphemeralAsNonEphemeral *TreatEphemeralAsNonEphemeral::create(
 }
 
 std::string TreatEphemeralAsNonEphemeral::getName() const {
-  llvm::SmallString<32> name;
+  std::string name;
   name += "treat ephemeral as non-ephemeral for ";
   name += ::getName(ConversionKind);
-  return name.c_str();
+  return name;
 }

test/attr/attributes.swift

@@ -286,10 +286,10 @@ func unownedOptionals(x: C) {
 
 // @_nonEphemeral attribute
 struct S1<T> {
-  func foo(@_nonEphemeral _ x: String) {} // expected-error {{@_nonEphemeral attribute currently only applies to pointer types}}
-  func bar(@_nonEphemeral _ x: T) {} // expected-error {{@_nonEphemeral attribute currently only applies to pointer types}}
+  func foo(@_nonEphemeral _ x: String) {} // expected-error {{@_nonEphemeral attribute only applies to pointer types}}
+  func bar(@_nonEphemeral _ x: T) {} // expected-error {{@_nonEphemeral attribute only applies to pointer types}}
 
-  func baz<U>(@_nonEphemeral _ x: U) {} // expected-error {{@_nonEphemeral attribute currently only applies to pointer types}}
+  func baz<U>(@_nonEphemeral _ x: U) {} // expected-error {{@_nonEphemeral attribute only applies to pointer types}}
 
   func qux(@_nonEphemeral _ x: UnsafeMutableRawPointer) {}
   func quux(@_nonEphemeral _ x: UnsafeMutablePointer<Int>?) {}