Revert "Turn off typealiases in protocols."

This reverts commit bda3983.

It breaks the internal compiler build

Author: eeckstein

include/swift/AST/DiagnosticsParse.def

@@ -771,8 +771,6 @@ ERROR(expected_close_after_else_directive,none,
       "further conditions after #else are unreachable", ())
 
 /// Associatedtype Statement
-WARNING(typealias_in_protocol_deprecated,none,
-      "use of 'typealias' to declare associated types is deprecated; use 'associatedtype' instead", ())
 ERROR(typealias_inside_protocol_without_type,none,
       "typealias is missing an assigned type; use 'associatedtype' to define an associated type requirement", ())
 ERROR(associatedtype_outside_protocol,none,

lib/Parse/ParseDecl.cpp

@@ -2175,11 +2175,7 @@ ParserStatus Parser::parseDecl(ParseDeclOptions Flags,
       break;
     }
     case tok::kw_typealias:
-      if (Flags.contains(PD_InProtocol)) {
-        DeclResult = parseDeclAssociatedType(Flags, Attributes);
-      } else {
-        DeclResult = parseDeclTypeAlias(Flags, Attributes);
-      }
+      DeclResult = parseDeclTypeAlias(Flags, Attributes);
       Status = DeclResult;
       break;
     case tok::kw_associatedtype:
@@ -3025,7 +3021,7 @@ ParserResult<TypeDecl> Parser::parseDeclAssociatedType(Parser::ParseDeclOptions
   // ask us to fix up leftover Swift 2 code intending to be an associatedtype.
   if (Tok.is(tok::kw_typealias)) {
     AssociatedTypeLoc = consumeToken(tok::kw_typealias);
-    diagnose(AssociatedTypeLoc, diag::typealias_in_protocol_deprecated)
+    diagnose(AssociatedTypeLoc, diag::typealias_inside_protocol_without_type)
         .fixItReplace(AssociatedTypeLoc, "associatedtype");
   } else {
     AssociatedTypeLoc = consumeToken(tok::kw_associatedtype);

test/Generics/associated_types.swift

@@ -173,7 +173,7 @@ struct C<a : B> : B { // expected-error {{type 'C<a>' does not conform to protoc
 
 // SR-511
 protocol sr511 {
-  typealias Foo // expected-warning {{use of 'typealias' to declare associated types is deprecated; use 'associatedtype' instead}} 
+  typealias Foo // expected-error {{typealias is missing an assigned type; use 'associatedtype' to define an associated type requirement}} 
 }
 
 associatedtype Foo = Int // expected-error {{associated types can only be defined in a protocol; define a type or introduce a 'typealias' to satisfy an associated type requirement}}

test/decl/typealias/typealias.swift

@@ -29,8 +29,8 @@ struct MyType<TyA, TyB> {
 
 protocol P {
   associatedtype X<T>  // expected-error {{associated types may not have a generic parameter list}}
-// FIXME Disabled until typealiases in protocols are entirely fixed
-//  typealias Y<T>       // fixme-error {{expected '=' in typealias declaration}}
+  
+  typealias Y<T>       // expected-error {{expected '=' in typealias declaration}}
 }
 
 typealias basicTypealias = Int
@@ -148,8 +148,6 @@ extension C<Int> {}  // expected-error {{constrained extension must be declared
 
 
 // Allow typealias inside protocol, but don't allow it in where clauses (at least not yet)
-// FIXME Disabled until typealiases in protocols are entirely fixed
-/*
 protocol Col {
   associatedtype Elem
   var elem: Elem { get }
@@ -229,23 +227,23 @@ protocol P2 {
     associatedtype B
 }
 
-func go3<T : P1, U : P2 where T.F == U.B>(_ x: T) -> U { // fixme-error {{typealias 'F' is too complex to be used as a generic constraint; use an associatedtype instead}} fixme-error {{'F' is not a member type of 'T'}}
+func go3<T : P1, U : P2 where T.F == U.B>(_ x: T) -> U { // expected-error {{typealias 'F' is too complex to be used as a generic constraint; use an associatedtype instead}} expected-error {{'F' is not a member type of 'T'}}
 }
 
 // Specific diagnosis for things that look like Swift 2.x typealiases
 protocol P3 {
-  typealias T // fixme-error {{typealias is missing an assigned type; use 'associatedtype' to define an associated type requirement}}
-  typealias U : P2 // fixme-error {{typealias is missing an assigned type; use 'associatedtype' to define an associated type requirement}}
+  typealias T // expected-error {{typealias is missing an assigned type; use 'associatedtype' to define an associated type requirement}}
+  typealias U : P2 // expected-error {{typealias is missing an assigned type; use 'associatedtype' to define an associated type requirement}}
 
-  associatedtype V : P2 = // fixme-error {{expected type in associatedtype declaration}}
+  associatedtype V : P2 = // expected-error {{expected type in associatedtype declaration}}
 }
 
 // Test for not crashing on self and recursive aliases
 protocol P4 {
   typealias X = Self
-  typealias Y = Self.Y // fixme-error {{type alias 'Y' circularly references itself}}
+  typealias Y = Self.Y // expected-error {{type alias 'Y' circularly references itself}}
 
   func getSelf() -> X
 }
-*/
+
 

validation-test/compiler_crashers_fixed/28288-swift-genericparamlist-getsubstitutionmap.swift renamed to validation-test/compiler_crashers/28288-swift-genericparamlist-getsubstitutionmap.swift

@@ -5,7 +5,7 @@
 // See http://swift.org/LICENSE.txt for license information
 // See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
 
-// RUN: not %target-swift-frontend %s -parse
+// RUN: not --crash %target-swift-frontend %s -parse
 // REQUIRES: asserts
 protocol A{
 typealias B<a>:A

validation-test/compiler_crashers/28268-swift-type-transform.swift renamed to validation-test/compiler_crashers_fixed/28268-swift-type-transform.swift

@@ -5,6 +5,6 @@
 // See http://swift.org/LICENSE.txt for license information
 // See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
 
-// RUN: not --crash %target-swift-frontend %s -parse
+// RUN: not %target-swift-frontend %s -parse
 var:{protocol a{struct A:a
 typealias e=A.e