[Parse] Skip type specifiers in middle of composition types

Like `P & inout P2`.
Don't bother to construct wrapped TypeRepr for them.

Author: rintaro

include/swift/AST/DiagnosticsParse.def

@@ -1280,6 +1280,8 @@ ERROR(attr_interpolated_string,none,
 
 ERROR(attr_only_at_non_local_scope, none,
       "attribute '%0' can only be used in a non-local scope", (StringRef))
+ERROR(attr_only_on_parameters_parse, none,
+      "'%0' may only be used on parameters", (StringRef))
 
 // Access control
 ERROR(attr_access_expected_set,none,

lib/Parse/ParseType.cpp

@@ -172,22 +172,14 @@ LayoutConstraint Parser::parseLayoutConstraint(Identifier LayoutConstraintID) {
 ParserResult<TypeRepr> Parser::parseTypeSimple(Diag<> MessageID,
                                                bool HandleCodeCompletion) {
   ParserResult<TypeRepr> ty;
-  // If this is an "inout" marker for an identifier type, consume the inout.
-  SourceLoc SpecifierLoc;
-  VarDecl::Specifier TypeSpecifier;
-  if (Tok.is(tok::kw_inout)) {
-    SpecifierLoc = consumeToken();
-    TypeSpecifier = VarDecl::Specifier::InOut;
-  } else if (Tok.is(tok::identifier)) {
-    if (Tok.getRawText().equals("__shared")) {
-      assert(false);
-      SpecifierLoc = consumeToken();
-      TypeSpecifier = VarDecl::Specifier::Shared;
-    } else if (Tok.getRawText().equals("__owned")) {
-      assert(false);
-      SpecifierLoc = consumeToken();
-      TypeSpecifier = VarDecl::Specifier::Owned;
-    }
+
+  if (Tok.is(tok::kw_inout) ||
+      (Tok.is(tok::identifier) && (Tok.getRawText().equals("__shared") ||
+                                   Tok.getRawText().equals("__owned")))) {
+    // Type specifier should already be parsed before here. This only happens
+    // for construct like 'P1 & inout P2'.
+    diagnose(Tok.getLoc(), diag::attr_only_on_parameters_parse, Tok.getText());
+    consumeToken();
   }
 
   switch (Tok.getKind()) {
@@ -297,24 +289,6 @@ ParserResult<TypeRepr> Parser::parseTypeSimple(Diag<> MessageID,
     break;
   }
 
-  // If we parsed any specifier, prepend it.
-  if (SpecifierLoc.isValid() && ty.isNonNull()) {
-    TypeRepr *repr = ty.get();
-    switch (TypeSpecifier) {
-    case VarDecl::Specifier::InOut:
-      repr = new (Context) InOutTypeRepr(repr, SpecifierLoc);
-      break;
-    case VarDecl::Specifier::Shared:
-      repr = new (Context) SharedTypeRepr(repr, SpecifierLoc);
-      break;
-    case VarDecl::Specifier::Owned:
-      break;
-    case VarDecl::Specifier::Var:
-      llvm_unreachable("tried to create var type specifier?");
-    }
-    ty = makeParserResult(repr);
-  }
-
   return ty;
 }
 

test/type/protocol_composition.swift

@@ -174,3 +174,7 @@ takesP1AndP2([AnyObject & protocol_composition.P1 & P2]())
 takesP1AndP2([AnyObject & P1 & protocol_composition.P2]())
 takesP1AndP2([DoesNotExist & P1 & P2]()) // expected-error {{use of unresolved identifier 'DoesNotExist'}}
 takesP1AndP2([Swift.DoesNotExist & P1 & P2]()) // expected-error {{module 'Swift' has no member named 'DoesNotExist'}}
+
+typealias T08 = P1 & inout P2 // expected-error {{'inout' may only be used on parameters}}
+typealias T09 = P1 & __shared P2 // expected-error {{'__shared' may only be used on parameters}}
+typealias T10 = P1 & __owned P2 // expected-error {{'__owned' may only be used on parameters}}