languages/go
languages/go
1
0
Fork 0
mirror of https://github.com/golang/go synced 2024-10-04 15:09:59 +00:00
Code Issues Packages Projects Releases Wiki Activity

cmd/compile: trim range typechecking

Browse source 
Most of the code is not necessary anymore.
Before we start changing how range works,
delete this code so it won't need updating.

Preparation for proposal #61405.

Change-Id: Ia6c6cc62b156e38a871279350a2e60c189967cac
Reviewed-on: https://go-review.googlesource.com/c/go/+/510536
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
This commit is contained in:
Russ Cox 2023-06-14 11:29:59 -04:00
parent 53895bf993
commit ade5a6232f
1 changed files with 16 additions and 75 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

91
src/cmd/compile/internal/typecheck/stmt.go
View file

@ -20,70 +20,6 @@ func RangeExprType(t *types.Type) *types.Type {
}
func typecheckrangeExpr(n *ir.RangeStmt) {
n.X = Expr(n.X)
if n.X.Type() == nil {
return
}
t := RangeExprType(n.X.Type())
// delicate little dance. see tcAssignList
if n.Key != nil && !ir.DeclaredBy(n.Key, n) {
n.Key = AssignExpr(n.Key)
}
if n.Value != nil && !ir.DeclaredBy(n.Value, n) {
n.Value = AssignExpr(n.Value)
}
var tk, tv *types.Type
toomany := false
switch t.Kind() {
default:
base.ErrorfAt(n.Pos(), errors.InvalidRangeExpr, "cannot range over %L", n.X)
return
case types.TARRAY, types.TSLICE:
tk = types.Types[types.TINT]
tv = t.Elem()
case types.TMAP:
tk = t.Key()
tv = t.Elem()
case types.TCHAN:
if !t.ChanDir().CanRecv() {
base.ErrorfAt(n.Pos(), errors.InvalidRangeExpr, "invalid operation: range %v (receive from send-only type %v)", n.X, n.X.Type())
return
}
tk = t.Elem()
tv = nil
if n.Value != nil {
toomany = true
}
case types.TSTRING:
tk = types.Types[types.TINT]
tv = types.RuneType
}
if toomany {
base.ErrorfAt(n.Pos(), errors.InvalidIterVar, "too many variables in range")
}
do := func(nn ir.Node, t *types.Type) {
if nn != nil {
if ir.DeclaredBy(nn, n) && nn.Type() == nil {
nn.SetType(t)
} else if nn.Type() != nil {
if op, why := Assignop(t, nn.Type()); op == ir.OXXX {
base.ErrorfAt(n.Pos(), errors.InvalidIterVar, "cannot assign type %v to %L in range%s", t, nn, why)
}
}
checkassign(nn)
}
}
do(n.Key, tk)
do(n.Value, tv)
}
// type check assignment.
@ -335,18 +271,23 @@ func tcIf(n *ir.IfStmt) ir.Node {
// range
func tcRange(n *ir.RangeStmt) {
// Typechecking order is important here:
// 0. first typecheck range expression (slice/map/chan),
// it is evaluated only once and so logically it is not part of the loop.
// 1. typecheck produced values,
// this part can declare new vars and so it must be typechecked before body,
// because body can contain a closure that captures the vars.
// 2. decldepth++ to denote loop body.
// 3. typecheck body.
// 4. decldepth--.
typecheckrangeExpr(n)
n.X = Expr(n.X)
// second half of dance, the first half being typecheckrangeExpr
// delicate little dance. see tcAssignList
if n.Key != nil {
if !ir.DeclaredBy(n.Key, n) {
n.Key = AssignExpr(n.Key)
}
checkassign(n.Key)
}
if n.Value != nil {
if !ir.DeclaredBy(n.Value, n) {
n.Value = AssignExpr(n.Value)
}
checkassign(n.Value)
}
// second half of dance
n.SetTypecheck(1)
if n.Key != nil && n.Key.Typecheck() == 0 {
n.Key = AssignExpr(n.Key)