package types
+// isValid reports whether t is a valid type.
+func isValid(t Type) bool { return _Unalias(t) != Typ[Invalid] }
+
// The isX predicates below report whether t is an X.
// If t is a type parameter the result is false; i.e.,
// these predicates don't look inside a type parameter.
// for all specific types of the type parameter's type set.
// allBasic(t, info) is an optimized version of isBasic(coreType(t), info).
func allBasic(t Type, info BasicInfo) bool {
- if tpar, _ := t.(*TypeParam); tpar != nil {
+ if tpar, _ := _Unalias(t).(*TypeParam); tpar != nil {
return tpar.is(func(t *term) bool { return t != nil && isBasic(t.typ, info) })
}
return isBasic(t, info)
// predeclared types, defined types, and type parameters.
// hasName may be called with types that are not fully set up.
func hasName(t Type) bool {
- switch t.(type) {
+ switch _Unalias(t).(type) {
case *Basic, *Named, *TypeParam:
return true
}
// This includes all non-defined types, but also basic types.
// isTypeLit may be called with types that are not fully set up.
func isTypeLit(t Type) bool {
- switch t.(type) {
+ switch _Unalias(t).(type) {
case *Named, *TypeParam:
return false
}
// constant or boolean. isTyped may be called with types that
// are not fully set up.
func isTyped(t Type) bool {
- // isTyped is called with types that are not fully
- // set up. Must not call under()!
+ // Alias or Named types cannot denote untyped types,
+ // thus we don't need to call _Unalias or under
+ // (which would be unsafe to do for types that are
+ // not fully set up).
b, _ := t.(*Basic)
return b == nil || b.info&IsUntyped == 0
}
// isTypeParam reports whether t is a type parameter.
func isTypeParam(t Type) bool {
- _, ok := t.(*TypeParam)
+ _, ok := _Unalias(t).(*TypeParam)
return ok
}
// use anywhere, but it may report a false negative if the type set has not been
// computed yet.
func hasEmptyTypeset(t Type) bool {
- if tpar, _ := t.(*TypeParam); tpar != nil && tpar.bound != nil {
+ if tpar, _ := _Unalias(t).(*TypeParam); tpar != nil && tpar.bound != nil {
iface, _ := safeUnderlying(tpar.bound).(*Interface)
return iface != nil && iface.tset != nil && iface.tset.IsEmpty()
}
// TODO(gri) should we include signatures or assert that they are not present?
func isGeneric(t Type) bool {
// A parameterized type is only generic if it doesn't have an instantiation already.
- named, _ := t.(*Named)
+ named := asNamed(t)
return named != nil && named.obj != nil && named.inst == nil && named.TypeParams().Len() > 0
}
// For changes to this code the corresponding changes should be made to unifier.nify.
func (c *comparer) identical(x, y Type, p *ifacePair) bool {
+ x = _Unalias(x)
+ y = _Unalias(y)
+
if x == y {
return true
}
- if c.ignoreInvalids && (x == Typ[Invalid] || y == Typ[Invalid]) {
+ if c.ignoreInvalids && (!isValid(x) || !isValid(y)) {
return true
}
case *Named:
// Two named types are identical if their type names originate
- // in the same type declaration.
- if y, ok := y.(*Named); ok {
+ // in the same type declaration; if they are instantiated they
+ // must have identical type argument lists.
+ if y := asNamed(y); y != nil {
+ // check type arguments before origins to match unifier
+ // (for correct source code we need to do all checks so
+ // order doesn't matter)
xargs := x.TypeArgs().list()
yargs := y.TypeArgs().list()
-
if len(xargs) != len(yargs) {
return false
}
-
- if len(xargs) > 0 {
- // Instances are identical if their original type and type arguments
- // are identical.
- if !Identical(x.Origin(), y.Origin()) {
+ for i, xarg := range xargs {
+ if !Identical(xarg, yargs[i]) {
return false
}
- for i, xa := range xargs {
- if !Identical(xa, yargs[i]) {
- return false
- }
- }
- return true
}
-
- // TODO(gri) Why is x == y not sufficient? And if it is,
- // we can just return false here because x == y
- // is caught in the very beginning of this function.
- return x.obj == y.obj
+ return identicalOrigin(x, y)
}
case *TypeParam:
return false
}
+// identicalOrigin reports whether x and y originated in the same declaration.
+func identicalOrigin(x, y *Named) bool {
+ // TODO(gri) is this correct?
+ return x.Origin().obj == y.Origin().obj
+}
+
// identicalInstance reports if two type instantiations are identical.
// Instantiations are identical if their origin and type arguments are
// identical.
// it returns the incoming type for all other types. The default type
// for untyped nil is untyped nil.
func Default(t Type) Type {
- if t, ok := t.(*Basic); ok {
+ if t, ok := _Unalias(t).(*Basic); ok {
switch t.kind {
case UntypedBool:
return Typ[Bool]
}
return t
}
+
+// maxType returns the "largest" type that encompasses both x and y.
+// If x and y are different untyped numeric types, the result is the type of x or y
+// that appears later in this list: integer, rune, floating-point, complex.
+// Otherwise, if x != y, the result is nil.
+func maxType(x, y Type) Type {
+ // We only care about untyped types (for now), so == is good enough.
+ // TODO(gri) investigate generalizing this function to simplify code elsewhere
+ if x == y {
+ return x
+ }
+ if isUntyped(x) && isUntyped(y) && isNumeric(x) && isNumeric(y) {
+ // untyped types are basic types
+ if x.(*Basic).kind > y.(*Basic).kind {
+ return x
+ }
+ return y
+ }
+ return nil
+}
+
+// clone makes a "flat copy" of *p and returns a pointer to the copy.
+func clone[P *T, T any](p P) P {
+ c := *p
+ return &c
+}