"cmd/compile/internal/ir"
	"cmd/compile/internal/reflectdata"
	"cmd/compile/internal/typecheck"
	"cmd/compile/internal/types"
	"cmd/internal/src"
)

// walkAssign walks an OAS (AssignExpr) or OASOP (AssignOpExpr) node.
func walkAssign(init *ir.Nodes, n ir.Node) ir.Node {
	init.Append(ir.TakeInit(n)...)

	var left, right ir.Node
	switch n.Op() {
	case ir.OAS:
		n := n.(*ir.AssignStmt)
		left, right = n.X, n.Y

	case ir.OCFUNC:
		return n

	case ir.OCALLINTER, ir.OCALLFUNC:
		n := n.(*ir.CallExpr)
		return walkCall(n, init)

	case ir.OAS, ir.OASOP:
		return walkAssign(init, n)

	case ir.OAS2:
		n := n.(*ir.AssignListStmt)
		return walkAssignList(init, n)

	// a,b,... = fn()
	case ir.OAS2FUNC:
		n := n.(*ir.AssignListStmt)
		return walkAssignFunc(init, n)

		// optimizations.
		//
		// First, we want to handle m[k] = append(m[k], ...) with a single
		// runtime call to mapassign. This requires the m[k] expressions to
		// satisfy ir.SameSafeExpr in walkAssign.
		//
		// But if k is a slow map key type that's passed by reference (e.g.,
		// byte), then we want to avoid marking user variables as addrtaken,
		// if that might prevent the compiler from keeping k in a register.