go/types: remove need for the instance struct

This is a port of CL 345177 to go/types.

Change-Id: I79fcfbf5b28e9a7a2e66c81bc831e164a8da8bbb
Reviewed-on: https://go-review.googlesource.com/c/go/+/346551
Trust: Robert Findley <rfindley@google.com>
Run-TryBot: Robert Findley <rfindley@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
This commit is contained in:
Robert Findley 2021-08-31 17:00:59 -04:00
parent d15a75e070
commit 580987cd58
3 changed files with 7 additions and 15 deletions

View file

@ -130,7 +130,7 @@ func (check *Checker) instance(pos token.Pos, typ Type, targs []Type) Type {
tname := NewTypeName(pos, t.obj.pkg, t.obj.name, nil)
named := check.newNamed(tname, t, nil, nil, nil) // methods and tparams are set when named is loaded
named.targs = NewTypeList(targs)
named.instance = &instance{pos}
named.instPos = &pos
if check != nil {
check.typMap[h] = named
}

View file

@ -17,7 +17,7 @@ type Named struct {
orig *Named // original, uninstantiated type
fromRHS Type // type (on RHS of declaration) this *Named type is derived of (for cycle reporting)
underlying Type // possibly a *Named during setup; never a *Named once set up completely
instance *instance // syntactic information for lazy instantiation
instPos *token.Pos // position information for lazy instantiation, or nil
tparams *TParamList // type parameters, or nil
targs *TypeList // type arguments (after instantiation), or nil
methods []*Func // methods declared for this type (not the method set of this type); signatures are type-checked lazily
@ -240,24 +240,16 @@ func (n *Named) setUnderlying(typ Type) {
}
}
// instance holds position information for use in lazy instantiation.
//
// TODO(rfindley): instance is probably unnecessary now. See if it can be
// eliminated.
type instance struct {
pos token.Pos // position of type instantiation; for error reporting only
}
// expand ensures that the underlying type of n is instantiated.
// The underlying type will be Typ[Invalid] if there was an error.
func (n *Named) expand(typMap map[string]*Named) *Named {
if n.instance != nil {
if n.instPos != nil {
// n must be loaded before instantiation, in order to have accurate
// tparams. This is done implicitly by the call to n.TParams, but making it
// explicit is harmless: load is idempotent.
n.load()
var u Type
if n.check.validateTArgLen(n.instance.pos, n.tparams.Len(), n.targs.Len()) {
if n.check.validateTArgLen(*n.instPos, n.tparams.Len(), n.targs.Len()) {
if typMap == nil {
if n.check != nil {
typMap = n.check.typMap
@ -270,13 +262,13 @@ func (n *Named) expand(typMap map[string]*Named) *Named {
typMap = map[string]*Named{h: n}
}
}
u = n.check.subst(n.instance.pos, n.orig.underlying, makeSubstMap(n.TParams().list(), n.targs.list()), typMap)
u = n.check.subst(*n.instPos, n.orig.underlying, makeSubstMap(n.TParams().list(), n.targs.list()), typMap)
} else {
u = Typ[Invalid]
}
n.underlying = u
n.fromRHS = u
n.instance = nil
n.instPos = nil
}
return n
}

View file

@ -197,7 +197,7 @@ func writeType(buf *bytes.Buffer, typ Type, qf Qualifier, visited []Type) {
}
case *Named:
if t.instance != nil {
if t.instPos != nil {
buf.WriteByte(instanceMarker)
}
writeTypeName(buf, t.obj, qf)