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[dev.typeparams] go/types: import universe changes from dev.go2go

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This is unmodified from the dev.go2go branch, except to remove the aType
embedding.

Change-Id: Id14d97a56d27ea609c43b453e8f9f1cf1a451406
Reviewed-on: https://go-review.googlesource.com/c/go/+/276252
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:
Rob Findley 2020-12-08 11:53:26 -05:00 committed by Robert Findley
parent 14dc2d2345
commit b6e678573d
1 changed files with 51 additions and 7 deletions
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58
src/go/types/universe.go
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@ -24,6 +24,7 @@ var (
universeIota *Const
universeByte *Basic // uint8 alias, but has name "byte"
universeRune *Basic // int32 alias, but has name "rune"
universeAny *Named
universeError *Named
)
@ -77,13 +78,24 @@ func defPredeclaredTypes() {
def(NewTypeName(token.NoPos, nil, t.name, t))
}
// any
// (Predeclared and entered into universe scope so we do all the
// usual checks; but removed again from scope later since it's
// only visible as constraint in a type parameter list.)
{
typ := &Named{underlying: &emptyInterface}
def(NewTypeName(token.NoPos, nil, "any", typ))
}
// Error has a nil package in its qualified name since it is in no package
res := NewVar(token.NoPos, nil, "", Typ[String])
sig := &Signature{results: NewTuple(res)}
err := NewFunc(token.NoPos, nil, "Error", sig)
typ := &Named{underlying: NewInterfaceType([]*Func{err}, nil).Complete()}
sig.recv = NewVar(token.NoPos, nil, "", typ)
def(NewTypeName(token.NoPos, nil, "error", typ))
{
res := NewVar(token.NoPos, nil, "", Typ[String])
sig := &Signature{results: NewTuple(res)}
err := NewFunc(token.NoPos, nil, "Error", sig)
typ := &Named{underlying: NewInterfaceType([]*Func{err}, nil).Complete()}
sig.recv = NewVar(token.NoPos, nil, "", typ)
def(NewTypeName(token.NoPos, nil, "error", typ))
}
}
var predeclaredConsts = [...]struct {
@ -188,6 +200,33 @@ func DefPredeclaredTestFuncs() {
def(newBuiltin(_Trace))
}
func defPredeclaredComparable() {
// The "comparable" interface can be imagined as defined like
//
// type comparable interface {
// == () untyped bool
// != () untyped bool
// }
//
// == and != cannot be user-declared but we can declare
// a magic method == and check for its presence when needed.
// Define interface { == () }. We don't care about the signature
// for == so leave it empty except for the receiver, which is
// set up later to match the usual interface method assumptions.
sig := new(Signature)
eql := NewFunc(token.NoPos, nil, "==", sig)
iface := NewInterfaceType([]*Func{eql}, nil).Complete()
// set up the defined type for the interface
obj := NewTypeName(token.NoPos, nil, "comparable", nil)
named := NewNamed(obj, iface, nil)
obj.color_ = black
sig.recv = NewVar(token.NoPos, nil, "", named) // complete == signature
def(obj)
}
func init() {
Universe = NewScope(nil, token.NoPos, token.NoPos, "universe")
Unsafe = NewPackage("unsafe", "unsafe")
@ -197,11 +236,16 @@ func init() {
defPredeclaredConsts()
defPredeclaredNil()
defPredeclaredFuncs()
defPredeclaredComparable()
universeIota = Universe.Lookup("iota").(*Const)
universeByte = Universe.Lookup("byte").(*TypeName).typ.(*Basic)
universeRune = Universe.Lookup("rune").(*TypeName).typ.(*Basic)
universeAny = Universe.Lookup("any").(*TypeName).typ.(*Named)
universeError = Universe.Lookup("error").(*TypeName).typ.(*Named)
// "any" is only visible as constraint in a type parameter list
delete(Universe.elems, "any")
}
// Objects with names containing blanks are internal and not entered into
@ -215,7 +259,7 @@ func def(obj Object) {
return // nothing to do
}
// fix Obj link for named types
if typ, ok := obj.Type().(*Named); ok {
if typ := asNamed(obj.Type()); typ != nil {
typ.obj = obj.(*TypeName)
}
// exported identifiers go into package unsafe