if n.TypeWord == nil || n.TypeWord.Op() == ir.OADDR && n.TypeWord.(*ir.AddrExpr).X.Op() == ir.OLINKSYMOFFSET {
		// Fixed (not loaded from a dictionary) type.
		ta := ir.NewTypeAssertExpr(base.Pos, c, toType)
		ta.SetOp(ir.ODOTTYPE2)
		// Allocate a descriptor for this conversion to pass to the runtime.
		ta.Descriptor = makeTypeAssertDescriptor(toType, true)
		rhs = ta
	} else {

	// because walkExpr will lower the string
	// conversion into a runtime call.
	// See issue 24937 for more discussion.
	if cond.Op() == ir.OBYTES2STR && allCaseExprsAreSideEffectFree(sw) {
		cond := cond.(*ir.ConvExpr)
		cond.SetOp(ir.OBYTES2STRTMP)
	}

	cond = walkExpr(cond, sw.PtrInit())
	if cond.Op() != ir.OLITERAL && cond.Op() != ir.ONIL {
		cond = copyExpr(cond, cond.Type(), &sw.Compiled)
	}

	base.Pos = lno

	s := exprSwitch{

	if n.RType != nil && n.RType.Op() == ir.OADDR {
		addr := n.RType.(*ir.AddrExpr)
		if addr.X.Op() == ir.OLINKSYMOFFSET {
			r := ir.NewTypeAssertExpr(n.Pos(), n.X, n.Type())
			if n.Op() == ir.ODYNAMICDOTTYPE2 {
				r.SetOp(ir.ODOTTYPE2)
			}
			r.SetType(n.Type())
			r.SetTypecheck(1)
			return walkExpr(r, init)
		}
	}
	return n
}

// walkIndex walks an OINDEX node.