diff options
Diffstat (limited to 'src/go/types/alias.go')
| -rw-r--r-- | src/go/types/alias.go | 37 |
1 files changed, 21 insertions, 16 deletions
diff --git a/src/go/types/alias.go b/src/go/types/alias.go index 8333a4d9c9..6043c0a984 100644 --- a/src/go/types/alias.go +++ b/src/go/types/alias.go @@ -23,11 +23,14 @@ type Alias struct { // NewAlias creates a new Alias type with the given type name and rhs. // rhs must not be nil. func NewAlias(obj *TypeName, rhs Type) *Alias { - return (*Checker)(nil).newAlias(obj, rhs) + alias := (*Checker)(nil).newAlias(obj, rhs) + // Ensure that alias.actual is set (#65455). + unalias(alias) + return alias } func (a *Alias) Obj() *TypeName { return a.obj } -func (a *Alias) Underlying() Type { return a.actual.Underlying() } +func (a *Alias) Underlying() Type { return unalias(a).Underlying() } func (a *Alias) String() string { return TypeString(a, nil) } // Type accessors @@ -38,24 +41,26 @@ func (a *Alias) String() string { return TypeString(a, nil) } // Consequently, the result is never an alias type. func Unalias(t Type) Type { if a0, _ := t.(*Alias); a0 != nil { - if a0.actual != nil { - return a0.actual - } - for a := a0; ; { - t = a.fromRHS - a, _ = t.(*Alias) - if a == nil { - break - } - } - if t == nil { - panic(fmt.Sprintf("non-terminated alias %s", a0.obj.name)) - } - a0.actual = t + return unalias(a0) } return t } +func unalias(a0 *Alias) Type { + if a0.actual != nil { + return a0.actual + } + var t Type + for a := a0; a != nil; a, _ = t.(*Alias) { + t = a.fromRHS + } + if t == nil { + panic(fmt.Sprintf("non-terminated alias %s", a0.obj.name)) + } + a0.actual = t + return t +} + // asNamed returns t as *Named if that is t's // actual type. It returns nil otherwise. func asNamed(t Type) *Named { |