Rename ErrorType to ErrorProtocol

Author: gribozavr

docs/ErrorHandling.rst

@@ -257,7 +257,7 @@ Throwing an error
 
 The ``throw`` statement begins the propagation of an error.  It always
 take an argument, which can be any value that conforms to the
-``ErrorType`` protocol (described below).
+``ErrorProtocol`` protocol (described below).
 
 ::
 
@@ -311,15 +311,15 @@ be marked ``throws``).
 
 We expect to refine the ``catch`` syntax with usage experience.
 
-``ErrorType``
--------------
+``ErrorProtocol``
+-----------------
 
-The Swift standard library will provide ``ErrorType``, a protocol with
+The Swift standard library will provide ``ErrorProtocol``, a protocol with
 a very small interface (which is not described in this proposal).  The
 standard pattern should be to define the conformance of an ``enum`` to
 the type::
 
-  enum HomeworkError : ErrorType {
+  enum HomeworkError : ErrorProtocol {
     case Overworked
     case Impossible
     case EatenByCat(Cat)
@@ -332,13 +332,13 @@ within that namespace, and optional values to attach to each option.
 Note that this corresponds very cleanly to the ``NSError`` model of an
 error domain, an error code, and optional user data.  We expect to
 import system error domains as enums that follow this approach and
-implement ``ErrorType``.  ``NSError`` and ``CFError`` themselves will also
-conform to ``ErrorType``.
+implement ``ErrorProtocol``.  ``NSError`` and ``CFError`` themselves will also
+conform to ``ErrorProtocol``.
 
 The physical representation (still being nailed down) will make it
-efficient to embed an ``NSError`` as an ``ErrorType`` and vice-versa.  It
+efficient to embed an ``NSError`` as an ``ErrorProtocol`` and vice-versa.  It
 should be possible to turn an arbitrary Swift ``enum`` that conforms to
-``ErrorType`` into an ``NSError`` by using the qualified type name as the
+``ErrorProtocol`` into an ``NSError`` by using the qualified type name as the
 domain key, the enumerator as the error code, and turning the payload
 into user data.
 

docs/ErrorHandlingRationale.rst

@@ -213,7 +213,7 @@ implementing it in the future:
   a major compatibility break.
 
 - With some admitted awkwardness, external exceptions can be reflected
-  into an ``ErrorType`` - like model automatically by the catch
+  into an ``ErrorProtocol`` - like model automatically by the catch
   mechanism.
 
 - In the meanwhile, developers who must handle an Objective-C
@@ -1521,12 +1521,12 @@ allowed in a blocking context.
 Error type
 ~~~~~~~~~~
 
-The Swift standard library will provide ``ErrorType``, a protocol with
+The Swift standard library will provide ``ErrorProtocol``, a protocol with
 a very small interface (which is not described in this proposal).  The
 standard pattern should be to define the conformance of an ``enum`` to
 the type::
 
-  enum HomeworkError : ErrorType {
+  enum HomeworkError : ErrorProtocol {
     case Overworked
     case Impossible
     case EatenByCat(Cat)
@@ -1543,13 +1543,13 @@ techniques for that will work fine in the future.
 Note that this corresponds very cleanly to the ``NSError`` model of an
 error domain, an error code, and optional user data.  We expect to
 import system error domains as enums that follow this approach and
-implement ``ErrorType``.  ``NSError`` and ``CFError`` themselves will also
-conform to ``ErrorType``.
+implement ``ErrorProtocol``.  ``NSError`` and ``CFError`` themselves will also
+conform to ``ErrorProtocol``.
 
 The physical representation (still being nailed down) will make it
-efficient to embed an ``NSError`` as an ``ErrorType`` and vice-versa.  It
+efficient to embed an ``NSError`` as an ``ErrorProtocol`` and vice-versa.  It
 should be possible to turn an arbitrary Swift ``enum`` that conforms to
-``ErrorType`` into an ``NSError`` by using the qualified type name as the
+``ErrorProtocol`` into an ``NSError`` by using the qualified type name as the
 domain key, the enumerator as the error code, and turning the payload
 into user data.
 
@@ -1806,9 +1806,9 @@ Let's wade into the details.
 Error types
 ~~~~~~~~~~~
 
-``NSError`` and ``CFError`` should implement the ``ErrorType`` protocol.  It
+``NSError`` and ``CFError`` should implement the ``ErrorProtocol`` protocol.  It
 should be possible to turn an arbitrary Swift ``enum`` that conforms to
-``ErrorType`` into an ``NSError`` by using the qualified type name as the
+``ErrorProtocol`` into an ``NSError`` by using the qualified type name as the
 domain key, the enumerator as the error code, and turning the payload
 into user data.
 
@@ -2028,7 +2028,7 @@ other words, we should not use table-based unwinding.
 
 Error propagation for universal errors should be handled by
 table-based unwinding.  ``catch`` handlers can catch both, mapping
-unwind exceptions to ``ErrorType`` values as necessary.  With a
+unwind exceptions to ``ErrorProtocol`` values as necessary.  With a
 carefully-designed interpretation function aimed to solve the specific
 needs of Swift, we can avoid most of the code-size impact by shifting
 it to the unwind tables, which needn't ever be loaded in the common

docs/Failable Initializers.rst

@@ -119,7 +119,7 @@ self value looks like it should have been consumed but it wasn't.
 
 It is also difficult to encode this tri-state return for throwing initializers.
 One can imagine changing the try_apply and throw SIL instructions to support
-returning a pair (ErrorType, AnyObject) instead of a single ErrorType. But
+returning a pair (ErrorProtocol, AnyObject) instead of a single ErrorProtocol. But
 this would ripple changes throughout various SIL analyses, and require IRGen
 to encode the pair return value in an efficient way.
 

docs/SIL.rst

@@ -3237,7 +3237,7 @@ container may use one of several representations:
   * `init_existential_metatype`_
   * `open_existential_metatype`_
 
-- **Boxed existential containers**: The standard library ``ErrorType`` protocol
+- **Boxed existential containers**: The standard library ``ErrorProtocol`` protocol
   uses a size-optimized reference-counted container, which indirectly stores
   the conforming value. Boxed existential containers can be ``retain``-ed
   and ``release``-d. The following instructions manipulate boxed existential
@@ -3249,21 +3249,21 @@ container may use one of several representations:
 
 Some existential types may additionally support specialized representations
 when they contain certain known concrete types. For example, when Objective-C
-interop is available, the ``ErrorType`` protocol existential supports
+interop is available, the ``ErrorProtocol`` protocol existential supports
 a class existential container representation for ``NSError`` objects, so it
 can be initialized from one using ``init_existential_ref`` instead of the
 more expensive ``alloc_existential_box``::
 
   bb(%nserror: $NSError):
-    // The slow general way to form an ErrorType, allocating a box and
+    // The slow general way to form an ErrorProtocol, allocating a box and
     // storing to its value buffer:
-    %error1 = alloc_existential_box $ErrorType, $NSError
+    %error1 = alloc_existential_box $ErrorProtocol, $NSError
     strong_retain %nserror: $NSError
     store %nserror to %error1#1 : $NSError
 
     // The fast path supported for NSError:
     strong_retain %nserror: $NSError
-    %error2 = init_existential_ref %nserror: $NSError, $ErrorType
+    %error2 = init_existential_ref %nserror: $NSError, $ErrorProtocol
 
 init_existential_addr
 `````````````````````

docs/proposals/EnumStyle.rst

@@ -40,7 +40,7 @@ amounts of language sugar it's given, vends initializers corresponding to
     init(success: Wrapped) {
       self = .Success(success)
     }
-    init(error: ErrorType) {
+    init(error: ErrorProtocol) {
       self = .Error(error)
     }
 
@@ -50,7 +50,7 @@ amounts of language sugar it's given, vends initializers corresponding to
       case .Error: return nil
       }
     }
-    var error: ErrorType? {
+    var error: ErrorProtocol? {
       switch self {
       case .Success: return nil
       case .Error(let error): return error
@@ -76,7 +76,7 @@ I'd like to start discussion by proposing the following:
 
     enum Result<Wrapped> {
       case init(success: Wrapped)
-      case init(error: ErrorType)
+      case init(error: ErrorProtocol)
     }
 
   Constructing a value of the case can then be done with the usual initializer
@@ -147,7 +147,7 @@ other kinds of initializer::
 
   enum Result<Wrapped> {
     case init(success: Wrapped)
-    case init(error: ErrorType)
+    case init(error: ErrorProtocol)
   }
 
   enum List<Element> {

docs/proposals/RemoteMirrors.rst

@@ -77,7 +77,7 @@ Boxes
 ~~~~~
 
 These are used for heap-allocating mutable values captured in closures, for
-indirect enum cases, and for ErrorType existential values. They have an
+indirect enum cases, and for ErrorProtocol existential values. They have an
 identifying isa pointer and reference count, but the isa pointer is shared by
 all boxes and thus does not describe the heap layout of the box.
 

include/swift/ABI/MetadataValues.h

@@ -196,8 +196,8 @@ enum class SpecialProtocol: uint8_t {
   None = 0,
   /// The AnyObject protocol.
   AnyObject = 1,
-  /// The ErrorType protocol.
-  ErrorType = 2,
+  /// The ErrorProtocol protocol.
+  ErrorProtocol = 2,
 };
 
 /// Identifiers for protocol method dispatch strategies.

include/swift/AST/ASTContext.h

@@ -352,8 +352,8 @@ class ASTContext {
   /// specified string.
   Identifier getIdentifier(StringRef Str) const;
 
-  /// Retrieve the declaration of Swift.ErrorType.
-  NominalTypeDecl *getExceptionTypeDecl() const;
+  /// Retrieve the declaration of Swift.ErrorProtocol.
+  NominalTypeDecl *getErrorProtocolDecl() const;
   CanType getExceptionType() const;
 
   /// Retrieve the declaration of Swift.Bool.

include/swift/AST/Builtins.def

@@ -344,13 +344,13 @@ BUILTIN_SIL_OPERATION(IsUniqueOrPinned_native, "isUniqueOrPinned_native",
   BUILTIN(Id, Name, Attrs)
 #endif
 
-/// willThrow: ErrorType -> ()
+/// willThrow: ErrorProtocol -> ()
 BUILTIN_RUNTIME_CALL(WillThrow, "willThrow", "n")
 
-/// unexpectedError: ErrorType -> ()
+/// unexpectedError: ErrorProtocol -> ()
 BUILTIN_RUNTIME_CALL(UnexpectedError, "unexpectedError", "")
 
-/// errorInMain: ErrorType -> ()
+/// errorInMain: ErrorProtocol -> ()
 BUILTIN_RUNTIME_CALL(ErrorInMain, "errorInMain", "")
 
 #undef BUILTIN_RUNTIME_CALL

include/swift/AST/DiagnosticsSema.def

@@ -243,9 +243,9 @@ ERROR(cannot_convert_to_return_type_nil,sema,none,
       "nil is incompatible with return type %0", (Type))
 
 ERROR(cannot_convert_thrown_type,sema,none,
-      "thrown expression type %0 does not conform to 'ErrorType'", (Type))
+      "thrown expression type %0 does not conform to 'ErrorProtocol'", (Type))
 ERROR(cannot_throw_nil,sema,none,
-      "cannot infer concrete ErrorType for thrown 'nil' value", ())
+      "cannot infer concrete ErrorProtocol for thrown 'nil' value", ())
 
 
 ERROR(cannot_convert_raw_initializer_value,sema,none,
@@ -1419,7 +1419,7 @@ ERROR(broken_equatable_requirement,sema_tcd,none,
 ERROR(broken_hashable_requirement,sema_tcd,none,
       "Hashable protocol is broken: unexpected requirement", ())
 ERROR(broken_errortype_requirement,sema_tcd,none,
-      "ErrorType protocol is broken: unexpected requirement", ())
+      "ErrorProtocol protocol is broken: unexpected requirement", ())
 ERROR(broken_int_hashable_conformance,sema_tcd,none,
       "Int type is broken: does not conform to Hashable", ())
 ERROR(broken_int_integer_literal_convertible_conformance,sema_tcd,none,
@@ -2179,7 +2179,7 @@ WARNING(no_throw_in_do_with_catch,sema,none,
 ERROR(sugar_type_not_found,sema_tct,none,
       "broken standard library: cannot find "
       "%select{Array|Optional|ImplicitlyUnwrappedOptional|Dictionary|"
-      "ErrorType}0 type", (unsigned))
+      "ErrorProtocol}0 type", (unsigned))
 ERROR(optional_intrinsics_not_found,sema_tct,none,
       "broken standard library: cannot find intrinsic operations on "
       "Optional<T>", ())

include/swift/AST/KnownDecls.def

@@ -57,8 +57,8 @@ FUNC_DECL(ForceBridgeFromObjectiveC,
           "_forceBridgeFromObjectiveC")
 FUNC_DECL(ConditionallyBridgeFromObjectiveC,
           "_conditionallyBridgeFromObjectiveC")
-FUNC_DECL(BridgeErrorTypeToNSError,
-          "_bridgeErrorTypeToNSError")
+FUNC_DECL(BridgeErrorProtocolToNSError,
+          "_bridgeErrorProtocolToNSError")
 
 FUNC_DECL(ForceBridgeFromObjectiveCBridgeable,
           "_forceBridgeFromObjectiveC_bridgeable")

include/swift/AST/KnownProtocols.def

@@ -56,7 +56,7 @@ PROTOCOL(RawRepresentable)
 PROTOCOL(Equatable)
 PROTOCOL(Hashable)
 PROTOCOL(Comparable)
-PROTOCOL(ErrorType)
+PROTOCOL(ErrorProtocol)
 PROTOCOL(OptionSetType)
 PROTOCOL_(BridgedNSError)
 

include/swift/Runtime/Metadata.h

@@ -1944,8 +1944,8 @@ enum class ExistentialTypeRepresentation {
   Opaque,
   /// The type uses a class existential representation.
   Class,
-  /// The type uses the ErrorType boxed existential representation.
-  ErrorType,
+  /// The type uses the ErrorProtocol boxed existential representation.
+  ErrorProtocol,
 };
 
 /// The structure of existential type metadata.

include/swift/SIL/BridgedTypes.def

@@ -47,7 +47,7 @@ BRIDGING_KNOWN_TYPE(Swift, String)
 BRIDGING_KNOWN_TYPE(ObjectiveC, ObjCBool)
 BRIDGING_KNOWN_TYPE(Darwin, DarwinBoolean)
 BRIDGING_KNOWN_TYPE(Swift, Bool)
-BRIDGING_KNOWN_TYPE(Swift, ErrorType)
+BRIDGING_KNOWN_TYPE(Swift, ErrorProtocol)
 
 BRIDGE_TYPE(Foundation, NSString, Swift, String, true)
 BRIDGE_TYPE(ObjectiveC, ObjCBool, Swift, Bool, false)

include/swift/SIL/DynamicCasts.h

@@ -78,8 +78,8 @@ void emitIndirectConditionalCastWithScalar(
 /// \brief Does the type conform to the _ObjectiveCBridgeable protocol.
 bool isObjectiveCBridgeable(ModuleDecl *M, CanType Ty);
 
-/// \brief Does the type conform to the _Error protocol.
-bool isErrorType(ModuleDecl *M, CanType Ty);
+/// \brief Does the type conform to ErrorProtocol.
+bool isErrorProtocol(ModuleDecl *M, CanType Ty);
 } // end namespace swift
 
 #endif

include/swift/SIL/TypeLowering.h

@@ -552,7 +552,6 @@ class TypeConverter {
 #define BRIDGING_KNOWN_TYPE(BridgedModule,BridgedType) \
   Optional<CanType> BridgedType##Ty;
 #include "swift/SIL/BridgedTypes.def"
-  Optional<CanType> BridgedTypeErrorType;
 
   const TypeLowering &getTypeLoweringForLoweredType(TypeKey key);
   const TypeLowering &getTypeLoweringForUncachedLoweredType(TypeKey key);

lib/AST/ASTContext.cpp

@@ -551,16 +551,16 @@ NominalTypeDecl *ASTContext::getStringDecl() const {
 }
 
 CanType ASTContext::getExceptionType() const {
-  if (auto exn = getExceptionTypeDecl()) {
+  if (auto exn = getErrorProtocolDecl()) {
     return exn->getDeclaredType()->getCanonicalType();
   } else {
     // Use Builtin.NativeObject just as a stand-in.
     return TheNativeObjectType;
   }
 }
 
-NominalTypeDecl *ASTContext::getExceptionTypeDecl() const {
-  return getProtocol(KnownProtocolKind::ErrorType);
+NominalTypeDecl *ASTContext::getErrorProtocolDecl() const {
+  return getProtocol(KnownProtocolKind::ErrorProtocol);
 }
 
 NominalTypeDecl *ASTContext::getArrayDecl() const {

lib/AST/ConformanceLookupTable.cpp

@@ -503,10 +503,10 @@ void ConformanceLookupTable::expandImpliedConformances(NominalTypeDecl *nominal,
         resolver->resolveInheritanceClause(cast<ExtensionDecl>(dc));
     }
 
-    // An @objc enum that explicitly conforms to the ErrorType protocol also
-    // implicitly conforms to _ObjectiveCBridgeableErrorType, via the known
-    // protocol _BridgedNSError.
-    if (conformingProtocol->isSpecificProtocol(KnownProtocolKind::ErrorType) &&
+    // An @objc enum that explicitly conforms to the ErrorProtocol protocol
+    // also implicitly conforms to _ObjectiveCBridgeableErrorProtocol, via the
+    // known protocol _BridgedNSError.
+    if (conformingProtocol->isSpecificProtocol(KnownProtocolKind::ErrorProtocol) &&
         isa<EnumDecl>(nominal) && nominal->isObjC() &&
         cast<EnumDecl>(nominal)->hasOnlyCasesWithoutAssociatedValues()) {
       ASTContext &ctx = nominal->getASTContext();

lib/AST/Decl.cpp

@@ -1889,8 +1889,8 @@ bool NominalTypeDecl::derivesProtocolConformance(ProtocolDecl *protocol) const {
   if (!knownProtocol)
     return false;
 
-  // All nominal types can derive their ErrorType conformance.
-  if (*knownProtocol == KnownProtocolKind::ErrorType)
+  // All nominal types can derive their ErrorProtocol conformance.
+  if (*knownProtocol == KnownProtocolKind::ErrorProtocol)
     return true;
 
   if (auto *enumDecl = dyn_cast<EnumDecl>(this)) {

lib/AST/Verifier.cpp

@@ -2588,7 +2588,7 @@ struct ASTNodeBase {};
     }
 
     Type checkExceptionTypeExists(const char *where) {
-      auto exn = Ctx.getExceptionTypeDecl();
+      auto exn = Ctx.getErrorProtocolDecl();
       if (exn) return exn->getDeclaredType();
 
       Out << "exception type does not exist in " << where << "\n";