base.AssertfAt(!typ.IsInterface(), pos, "want non-interface type, have %v", typ)
	return TypePtrAt(pos, typ)
}

// AppendElemRType asserts that n is an "append" operation, and
// returns an expression that yields the *runtime._type value
// representing the result slice type's element type.
func AppendElemRType(pos src.XPos, n *ir.CallExpr) ir.Node {
	assertOp(n, ir.OAPPEND)
	if hasRType(n, n.RType, "RType") {
		return n.RType
	}

		}
		as.Y = r
		if r.Op() == ir.OAPPEND {
			r := r.(*ir.CallExpr)
			// Left in place for back end.
			// Do not add a new write barrier.
			// Set up address of type for back end.
			r.Fun = reflectdata.AppendElemRType(base.Pos, r)
			return as
		}
		// Otherwise, lowered for race detector.
		// Treat as ordinary assignment.
	}

	if as.X != nil && as.Y != nil {
		return convas(as, init)
	}
	return as
}