if hasRType(n, n.RType, "RType") {
		return n.RType
	}
	return mapRType(pos, n.X.Type())
}

// UnsafeSliceElemRType asserts that n is an "unsafe.Slice" operation,
// and returns an expression that yields the *runtime._type value
// representing the result slice type's element type.
func UnsafeSliceElemRType(pos src.XPos, n *ir.BinaryExpr) ir.Node {
	assertOp(n, ir.OUNSAFESLICE)
	if hasRType(n, n.RType, "RType") {

	if ir.ShouldCheckPtr(ir.CurFunc, 1) {
		fnname := "unsafeslicecheckptr"
		fn := typecheck.LookupRuntime(fnname)
		init.Append(mkcall1(fn, nil, init, reflectdata.UnsafeSliceElemRType(base.Pos, n), unsafePtr, typecheck.Conv(len, lenType)))
	} else {
		// Otherwise, open code unsafe.Slice to prevent runtime call overhead.
		// Keep this code in sync with runtime.unsafeslice{,64}