[dev.typeparams] cmd/compile: use new converter functions rather than methods (fix build)

Change-Id: I4dcaca1f2e67ee32f70c22b2efa586232ca519bb
Reviewed-on: https://go-review.googlesource.com/c/go/+/293958
Trust: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Dan Scales <danscales@google.com>
TryBot-Result: Go Bot <gobot@golang.org>

src/cmd/compile/internal/noder/expr.go

@@ -237,15 +237,15 @@ func (g *irgen) selectorExpr(pos src.XPos, typ types2.Type, expr *syntax.Selecto
 			}
 			recvType2Base := recvType2
 			if wantPtr {
-				recvType2Base = recvType2.Pointer().Elem()
+				recvType2Base = types2.AsPointer(recvType2).Elem()
 			}
-			if len(recvType2Base.Named().TParams()) > 0 {
+			if len(types2.AsNamed(recvType2Base).TParams()) > 0 {
 				// recvType2 is the original generic type that is
 				// instantiated for this method call.
 				// selinfo.Recv() is the instantiated type
 				recvType2 = recvType2Base
 				// method is the generic method associated with the gen type
-				method := g.obj(recvType2.Named().Method(last))
+				method := g.obj(types2.AsNamed(recvType2).Method(last))
 				n = ir.NewSelectorExpr(pos, ir.OCALLPART, x, method.Sym())
 				n.(*ir.SelectorExpr).Selection = types.NewField(pos, method.Sym(), method.Type())
 				n.(*ir.SelectorExpr).Selection.Nname = method

src/cmd/compile/internal/types2/selection.go

@@ -55,11 +55,11 @@ func (s *Selection) Recv() Type { return s.recv }
 // TODO(gri):  fix this bug.
 func (s *Selection) TArgs() []Type {
 	r := s.recv
-	if r.Pointer() != nil {
-		r = r.Pointer().Elem()
+	if p := asPointer(r); p != nil {
+		r = p.Elem()
 	}
-	if r.Named() != nil {
-		return r.Named().TArgs()
+	if n := asNamed(r); n != nil {
+		return n.TArgs()
 	}
 	// The base type (after skipping any pointer) must be a Named type. The
 	// bug is that sometimes it can be an instance type (which is supposed to

src/cmd/compile/internal/types2/type.go

@@ -971,3 +971,8 @@ func asTypeParam(t Type) *TypeParam {
 	u, _ := under(t).(*TypeParam)
 	return u
 }
+
+// Exported for the compiler.
+
+func AsPointer(t Type) *Pointer { return asPointer(t) }
+func AsNamed(t Type) *Named     { return asNamed(t) }