diff options
Diffstat (limited to 'src/go/types/named.go')
| -rw-r--r-- | src/go/types/named.go | 38 |
1 files changed, 22 insertions, 16 deletions
diff --git a/src/go/types/named.go b/src/go/types/named.go index 66ae012379..00fde16445 100644 --- a/src/go/types/named.go +++ b/src/go/types/named.go @@ -219,6 +219,21 @@ func (n *Named) setUnderlying(typ Type) { } } +// bestEnv returns the best available environment. In order of preference: +// - the given env, if non-nil +// - the Checker env, if check is non-nil +// - a new environment +func (check *Checker) bestEnv(env *Environment) *Environment { + if env != nil { + return env + } + if check != nil { + assert(check.conf.Environment != nil) + return check.conf.Environment + } + return NewEnvironment() +} + // expandNamed ensures that the underlying type of n is instantiated. // The underlying type will be Typ[Invalid] if there was an error. func expandNamed(env *Environment, n *Named, instPos token.Pos) (tparams *TypeParamList, underlying Type, methods []*Func) { @@ -227,24 +242,15 @@ func expandNamed(env *Environment, n *Named, instPos token.Pos) (tparams *TypePa check := n.check if check.validateTArgLen(instPos, n.orig.tparams.Len(), n.targs.Len()) { - // TODO(rfindley): handling an optional Checker and Environment here (and - // in subst) feels overly complicated. Can we simplify? - if env == nil { - if check != nil { - env = check.conf.Environment - } else { - // If we're instantiating lazily, we might be outside the scope of a - // type-checking pass. In that case we won't have a pre-existing - // environment, but don't want to create a duplicate of the current - // instance in the process of expansion. - env = NewEnvironment() - } - h := env.typeHash(n.orig, n.targs.list()) - // ensure that an instance is recorded for h to avoid infinite recursion. - env.typeForHash(h, n) - } + // We must always have an env, to avoid infinite recursion. + env = check.bestEnv(env) + h := env.typeHash(n.orig, n.targs.list()) + // ensure that an instance is recorded for h to avoid infinite recursion. + env.typeForHash(h, n) + smap := makeSubstMap(n.orig.tparams.list(), n.targs.list()) underlying = n.check.subst(instPos, n.orig.underlying, smap, env) + for i := 0; i < n.orig.NumMethods(); i++ { origm := n.orig.Method(i) |