go/parser: resolve the type name when parsing a composite lit value

parsePrimaryExpr has to be careful to resolve identifiers used in
composite expressions when parsing in LHS mode. It missed the literal
type name.

Fixes #45136

Change-Id: I3e12f91e3ef5fdb43faa436cdf1240eb3293fe1a
Reviewed-on: https://go-review.googlesource.com/c/go/+/304451
Trust: Robert Findley <rfindley@google.com>
Run-TryBot: Robert Findley <rfindley@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>

src/go/parser/parser.go

@@ -1804,6 +1804,11 @@ func (p *parser) parsePrimaryExpr(lhs bool) (x ast.Expr) {
 				p.error(t.Pos(), "cannot parenthesize type in composite literal")
 				// already progressed, no need to advance
 			}
+			if lhs {
+				// An error has already been reported above, but try to resolve the 'T'
+				// in (T){...} anyway.
+				p.resolve(t)
+			}
 			x = p.parseLiteralValue(x)
 		default:
 			return

src/go/parser/testdata/resolution/issue45136.src

@@ -12,17 +12,15 @@ func _ /* =@blank */ () {
 	var foo /* =@foo */ = "foo"
 	obj /* @obj */ ["foo"]
 	obj /* @obj */ .run()
-
-	// TODO(#45136): the next two statements are missing objects.
-	obj{
+	obj /* @obj */ {
 		name: foo /* @foo */,
 	}
-	obj{
+	obj /* @obj */ {
 		name: "bar",
 	}.run()
 
-	var _ /* @=blank4 */ = File{key: obj /* @obj */{}}
-	var _ /* @=blank3 */ = File{obj{}}
+	var _ /* @=blank4 */ = File{key: obj /* @obj */ {}}
+	var _ /* @=blank3 */ = File{obj /* @obj */ {}}
 
 	[]obj /* @obj */ {foo /* @foo */}
 	x /* =@x1 */ := obj /* @obj */{}