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cmd/compile/internal/types2: consolidate verification logic

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Change an internal call of instantiateLazy to call Instantiate, so that
we can consolidate the logic for invoking verification.

This made verification of signatures lazy, which is not necessary but
should be harmless.

Change-Id: I2e59b04ac859e08c2e2910ded3c183093d1e34a7
Reviewed-on: https://go-review.googlesource.com/c/go/+/342149
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 2021-08-13 13:52:55 -04:00
parent 165ebd85a7
commit 8f0578ef39
2 changed files with 26 additions and 25 deletions
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49
src/cmd/compile/internal/types2/instantiate.go
View File

@ -26,12 +26,12 @@ import (
// instantiated.
func (check *Checker) Instantiate(pos syntax.Pos, typ Type, targs []Type, posList []syntax.Pos, verify bool) (res Type) {
// TODO(gri) What is better here: work with TypeParams, or work with TypeNames?
var tparams []*TypeName
var inst Type
switch t := typ.(type) {
case *Named:
return check.instantiateLazy(pos, t, targs, posList, verify)
inst = check.instantiateLazy(pos, t, targs)
case *Signature:
tparams = t.TParams().list()
tparams := t.TParams().list()
defer func() {
// If we had an unexpected failure somewhere don't panic below when
// asserting res.(*Signature). Check for *Signature in case Typ[Invalid]
@ -50,18 +50,35 @@ func (check *Checker) Instantiate(pos syntax.Pos, typ Type, targs []Type, posLis
// anymore; we need to set tparams to nil.
res.(*Signature).tparams = nil
}()
inst = check.instantiate(pos, typ, tparams, targs, nil)
default:
// only types and functions can be generic
panic(fmt.Sprintf("%v: cannot instantiate %v", pos, typ))
}
inst := check.instantiate(pos, typ, tparams, targs, nil)
if verify {
assert(len(posList) <= len(targs))
if len(tparams) == len(targs) {
check.verify(pos, tparams, targs, posList)
if check == nil {
panic("cannot have nil Checker if verifying constraints")
}
assert(len(posList) <= len(targs))
check.later(func() {
// Collect tparams again because lazily loaded *Named types may not have
// had tparams set up above.
var tparams []*TypeName
switch t := typ.(type) {
case *Named:
tparams = t.TParams().list()
case *Signature:
tparams = t.TParams().list()
}
// Avoid duplicate errors; instantiate will have complained if tparams
// and targs do not have the same length.
if len(tparams) == len(targs) {
check.verify(pos, tparams, targs, posList)
}
})
}
return inst
}
@ -101,20 +118,7 @@ func (check *Checker) instantiate(pos syntax.Pos, typ Type, tparams []*TypeName,
// instantiateLazy avoids actually instantiating the type until needed. typ
// must be a *Named type.
func (check *Checker) instantiateLazy(pos syntax.Pos, orig *Named, targs []Type, posList []syntax.Pos, verify bool) Type {
if verify {
if check == nil {
// Provide a more useful panic instead of panicking at check.later below.
panic("cannot have nil Checker if verifying constraints")
}
assert(len(posList) <= len(targs))
if orig.TParams().Len() == len(targs) {
check.later(func() {
check.verify(pos, orig.tparams.list(), targs, posList)
})
}
}
func (check *Checker) instantiateLazy(pos syntax.Pos, orig *Named, targs []Type) Type {
h := instantiatedHash(orig, targs)
if check != nil {
// typ may already have been instantiated with identical type arguments. In
@ -136,9 +140,6 @@ func (check *Checker) instantiateLazy(pos syntax.Pos, orig *Named, targs []Type,
}
func (check *Checker) verify(pos syntax.Pos, tparams []*TypeName, targs []Type, posList []syntax.Pos) {
if check == nil {
panic("cannot have nil Checker if verifying constraints")
}
smap := makeSubstMap(tparams, targs)
for i, tname := range tparams {
// best position for error reporting

2
src/cmd/compile/internal/types2/typexpr.go
View File

@ -444,7 +444,7 @@ func (check *Checker) instantiatedType(x syntax.Expr, targsx []syntax.Expr, def
posList[i] = syntax.StartPos(arg)
}
typ := check.instantiateLazy(x.Pos(), base, targs, posList, true)
typ := check.Instantiate(x.Pos(), base, targs, posList, true)
def.setUnderlying(typ)
// make sure we check instantiation works at least once