[consume] Fix consume parsing so we handle code completion and dollaridentifiers correctly.

This resulted from explorations around implementing the copy expr.

rdar://109479131

Author: gottesmm

lib/Parse/ParseExpr.cpp

@@ -409,14 +409,15 @@ ParserResult<Expr> Parser::parseExprSequenceElement(Diag<> message,
   }
 
   if (Tok.isContextualKeyword("consume")
-      && peekToken().isAny(tok::identifier, tok::kw_self)
+      && peekToken().isAny(tok::identifier, tok::kw_self, tok::dollarident,
+                           tok::code_complete)
       && !peekToken().isAtStartOfLine()) {
     Tok.setKind(tok::contextual_keyword);
 
     SourceLoc consumeLoc = consumeToken();
     ParserResult<Expr> sub =
         parseExprSequenceElement(diag::expected_expr_after_move, isExprBasic);
-    if (!sub.hasCodeCompletion() && !sub.isNull()) {
+    if (!sub.isNull()) {
       sub = makeParserResult(new (Context) MoveExpr(consumeLoc, sub.get()));
     }
     return sub;

test/IDE/move_expr.swift

@@ -0,0 +1,7 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-ide-test -batch-code-completion -source-filename %s -filecheck %raw-FileCheck -completion-output-dir %t
+
+func test(myParam: Int) {
+  consume #^CONSUME^#
+  // CONSUME: Decl[LocalVar]/Local:               myParam[#Int#]; name=myParam
+}

test/Parse/move_expr.swift

@@ -81,3 +81,22 @@ struct Foo {
         _ = consume $wrapperTest // expected-error{{can only be applied to lvalues}}
     }
 }
+
+func testParseConsumeWithDollarIdentifier() {
+  class Klass {}
+  let f: (Klass) -> () = {
+    let _ = consume $0
+  }
+  _ = f
+}
+
+class ParentKlass {}
+class ChildKlass : ParentKlass {}
+
+func testAsBindingVariableInSwitch(_ x: ChildKlass) {
+  switch x {
+  case let consume as ParentKlass:
+    _ = consume
+    break
+  }
+}