package types2
-// isNamed reports whether typ has a name.
-// isNamed may be called with types that are not fully set up.
-func isNamed(typ Type) bool {
- switch typ.(type) {
- case *Basic, *Named, *TypeParam, *instance:
- return true
- }
- return false
+// 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.
+
+func isBoolean(t Type) bool { return isBasic(t, IsBoolean) }
+func isInteger(t Type) bool { return isBasic(t, IsInteger) }
+func isUnsigned(t Type) bool { return isBasic(t, IsUnsigned) }
+func isFloat(t Type) bool { return isBasic(t, IsFloat) }
+func isComplex(t Type) bool { return isBasic(t, IsComplex) }
+func isNumeric(t Type) bool { return isBasic(t, IsNumeric) }
+func isString(t Type) bool { return isBasic(t, IsString) }
+func isIntegerOrFloat(t Type) bool { return isBasic(t, IsInteger|IsFloat) }
+func isConstType(t Type) bool { return isBasic(t, IsConstType) }
+
+// isBasic reports whether under(t) is a basic type with the specified info.
+// If t is a type parameter the result is false; i.e.,
+// isBasic does not look inside a type parameter.
+func isBasic(t Type, info BasicInfo) bool {
+ u, _ := under(t).(*Basic)
+ return u != nil && u.info&info != 0
}
-// isGeneric reports whether a type is a generic, uninstantiated type (generic
-// signatures are not included).
-func isGeneric(typ Type) bool {
- // A parameterized type is only instantiated if it doesn't have an instantiation already.
- named, _ := typ.(*Named)
- return named != nil && named.obj != nil && named.TParams() != nil && named.targs == nil
+// The allX predicates below report whether t is an X.
+// If t is a type parameter the result is true if isX is true
+// for all specified types of the type parameter's type set.
+// allX is an optimized version of isX(coreType(t)) (which
+// is the same as underIs(t, isX)).
+
+func allBoolean(t Type) bool { return allBasic(t, IsBoolean) }
+func allInteger(t Type) bool { return allBasic(t, IsInteger) }
+func allUnsigned(t Type) bool { return allBasic(t, IsUnsigned) }
+func allNumeric(t Type) bool { return allBasic(t, IsNumeric) }
+func allString(t Type) bool { return allBasic(t, IsString) }
+func allOrdered(t Type) bool { return allBasic(t, IsOrdered) }
+func allNumericOrString(t Type) bool { return allBasic(t, IsNumeric|IsString) }
+
+// allBasic reports whether under(t) is a basic type with the specified info.
+// If t is a type parameter, the result is true if isBasic(t, info) is true
+// 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, _ := _Unalias(t).(*TypeParam); tpar != nil {
+ return tpar.is(func(t *term) bool { return t != nil && isBasic(t.typ, info) })
+ }
+ return isBasic(t, info)
}
-func is(typ Type, what BasicInfo) bool {
- switch t := under(typ).(type) {
- case *Basic:
- return t.info&what != 0
- case *TypeParam:
- return t.underIs(func(t Type) bool { return is(t, what) })
+// hasName reports whether t has a name. This includes
+// 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 _Unalias(t).(type) {
+ case *Basic, *Named, *TypeParam:
+ return true
}
return false
}
-func isBoolean(typ Type) bool { return is(typ, IsBoolean) }
-func isInteger(typ Type) bool { return is(typ, IsInteger) }
-func isUnsigned(typ Type) bool { return is(typ, IsUnsigned) }
-func isFloat(typ Type) bool { return is(typ, IsFloat) }
-func isComplex(typ Type) bool { return is(typ, IsComplex) }
-func isNumeric(typ Type) bool { return is(typ, IsNumeric) }
-func isString(typ Type) bool { return is(typ, IsString) }
-
-// Note that if typ is a type parameter, isInteger(typ) || isFloat(typ) does not
-// produce the expected result because a type list that contains both an integer
-// and a floating-point type is neither (all) integers, nor (all) floats.
-// Use isIntegerOrFloat instead.
-func isIntegerOrFloat(typ Type) bool { return is(typ, IsInteger|IsFloat) }
-
-// isNumericOrString is the equivalent of isIntegerOrFloat for isNumeric(typ) || isString(typ).
-func isNumericOrString(typ Type) bool { return is(typ, IsNumeric|IsString) }
+// isTypeLit reports whether t is a type literal.
+// 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 _Unalias(t).(type) {
+ case *Named, *TypeParam:
+ return false
+ }
+ return true
+}
-// isTyped reports whether typ is typed; i.e., not an untyped
+// isTyped reports whether t is typed; i.e., not an untyped
// constant or boolean. isTyped may be called with types that
// are not fully set up.
-func isTyped(typ Type) bool {
- // isTyped is called with types that are not fully
- // set up. Must not call asBasic()!
- // A *Named or *instance type is always typed, so
- // we only need to check if we have a true *Basic
- // type.
- t, _ := typ.(*Basic)
- return t == nil || t.info&IsUntyped == 0
+func isTyped(t Type) bool {
+ // 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
+}
+
+// isUntyped(t) is the same as !isTyped(t).
+func isUntyped(t Type) bool {
+ return !isTyped(t)
+}
+
+// IsInterface reports whether t is an interface type.
+func IsInterface(t Type) bool {
+ _, ok := under(t).(*Interface)
+ return ok
}
-// isUntyped(typ) is the same as !isTyped(typ).
-func isUntyped(typ Type) bool {
- return !isTyped(typ)
+// isNonTypeParamInterface reports whether t is an interface type but not a type parameter.
+func isNonTypeParamInterface(t Type) bool {
+ return !isTypeParam(t) && IsInterface(t)
}
-func isOrdered(typ Type) bool { return is(typ, IsOrdered) }
+// isTypeParam reports whether t is a type parameter.
+func isTypeParam(t Type) bool {
+ _, ok := _Unalias(t).(*TypeParam)
+ return ok
+}
-func isConstType(typ Type) bool {
- // Type parameters are never const types.
- t, _ := under(typ).(*Basic)
- return t != nil && t.info&IsConstType != 0
+// hasEmptyTypeset reports whether t is a type parameter with an empty type set.
+// The function does not force the computation of the type set and so is safe to
+// 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, _ := _Unalias(t).(*TypeParam); tpar != nil && tpar.bound != nil {
+ iface, _ := safeUnderlying(tpar.bound).(*Interface)
+ return iface != nil && iface.tset != nil && iface.tset.IsEmpty()
+ }
+ return false
}
-// IsInterface reports whether typ is an interface type.
-func IsInterface(typ Type) bool {
- return asInterface(typ) != nil
+// isGeneric reports whether a type is a generic, uninstantiated type
+// (generic signatures are not included).
+// 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 := asNamed(t)
+ return named != nil && named.obj != nil && named.inst == nil && named.TypeParams().Len() > 0
}
// Comparable reports whether values of type T are comparable.
func Comparable(T Type) bool {
- return comparable(T, nil)
+ return comparable(T, true, nil, nil)
}
-func comparable(T Type, seen map[Type]bool) bool {
+// If dynamic is set, non-type parameter interfaces are always comparable.
+// If reportf != nil, it may be used to report why T is not comparable.
+func comparable(T Type, dynamic bool, seen map[Type]bool, reportf func(string, ...interface{})) bool {
if seen[T] {
return true
}
}
seen[T] = true
- // If T is a type parameter not constrained by any type
- // (i.e., it's operational type is the top type),
- // T is comparable if it has the == method. Otherwise,
- // the operational type "wins". For instance
- //
- // interface{ comparable; type []byte }
- //
- // is not comparable because []byte is not comparable.
- // TODO(gri) this code is not 100% correct (see comment for TypeSet.IsComparable)
- if t := asTypeParam(T); t != nil && optype(t) == theTop {
- return t.Bound().IsComparable()
- }
-
switch t := under(T).(type) {
case *Basic:
// assume invalid types to be comparable
// to avoid follow-up errors
return t.kind != UntypedNil
- case *Pointer, *Interface, *Chan:
+ case *Pointer, *Chan:
return true
case *Struct:
for _, f := range t.fields {
- if !comparable(f.typ, seen) {
+ if !comparable(f.typ, dynamic, seen, nil) {
+ if reportf != nil {
+ reportf("struct containing %s cannot be compared", f.typ)
+ }
return false
}
}
return true
case *Array:
- return comparable(t.elem, seen)
- case *TypeParam:
- return t.underIs(func(t Type) bool {
- return comparable(t, seen)
- })
+ if !comparable(t.elem, dynamic, seen, nil) {
+ if reportf != nil {
+ reportf("%s cannot be compared", t)
+ }
+ return false
+ }
+ return true
+ case *Interface:
+ if dynamic && !isTypeParam(T) || t.typeSet().IsComparable(seen) {
+ return true
+ }
+ if reportf != nil {
+ if t.typeSet().IsEmpty() {
+ reportf("empty type set")
+ } else {
+ reportf("incomparable types in type set")
+ }
+ }
+ // fallthrough
}
return false
}
-// hasNil reports whether a type includes the nil value.
-func hasNil(typ Type) bool {
- switch t := under(typ).(type) {
+// hasNil reports whether type t includes the nil value.
+func hasNil(t Type) bool {
+ switch u := under(t).(type) {
case *Basic:
- return t.kind == UnsafePointer
- case *Slice, *Pointer, *Signature, *Interface, *Map, *Chan:
+ return u.kind == UnsafePointer
+ case *Slice, *Pointer, *Signature, *Map, *Chan:
return true
- case *TypeParam:
- return t.underIs(hasNil)
+ case *Interface:
+ return !isTypeParam(t) || u.typeSet().underIs(func(u Type) bool {
+ return u != nil && hasNil(u)
+ })
}
return false
}
return p.x == q.x && p.y == q.y || p.x == q.y && p.y == q.x
}
+// A comparer is used to compare types.
+type comparer struct {
+ ignoreTags bool // if set, identical ignores struct tags
+ ignoreInvalids bool // if set, identical treats an invalid type as identical to any type
+}
+
// For changes to this code the corresponding changes should be made to unifier.nify.
-func identical(x, y Type, cmpTags bool, p *ifacePair) bool {
- // types must be expanded for comparison
- x = expandf(x)
- y = expandf(y)
+func (c *comparer) identical(x, y Type, p *ifacePair) bool {
+ x = _Unalias(x)
+ y = _Unalias(y)
if x == y {
return true
}
+ if c.ignoreInvalids && (!isValid(x) || !isValid(y)) {
+ return true
+ }
+
switch x := x.(type) {
case *Basic:
// Basic types are singletons except for the rune and byte
if y, ok := y.(*Array); ok {
// If one or both array lengths are unknown (< 0) due to some error,
// assume they are the same to avoid spurious follow-on errors.
- return (x.len < 0 || y.len < 0 || x.len == y.len) && identical(x.elem, y.elem, cmpTags, p)
+ return (x.len < 0 || y.len < 0 || x.len == y.len) && c.identical(x.elem, y.elem, p)
}
case *Slice:
// Two slice types are identical if they have identical element types.
if y, ok := y.(*Slice); ok {
- return identical(x.elem, y.elem, cmpTags, p)
+ return c.identical(x.elem, y.elem, p)
}
case *Struct:
for i, f := range x.fields {
g := y.fields[i]
if f.embedded != g.embedded ||
- cmpTags && x.Tag(i) != y.Tag(i) ||
+ !c.ignoreTags && x.Tag(i) != y.Tag(i) ||
!f.sameId(g.pkg, g.name) ||
- !identical(f.typ, g.typ, cmpTags, p) {
+ !c.identical(f.typ, g.typ, p) {
return false
}
}
case *Pointer:
// Two pointer types are identical if they have identical base types.
if y, ok := y.(*Pointer); ok {
- return identical(x.base, y.base, cmpTags, p)
+ return c.identical(x.base, y.base, p)
}
case *Tuple:
if x != nil {
for i, v := range x.vars {
w := y.vars[i]
- if !identical(v.typ, w.typ, cmpTags, p) {
+ if !c.identical(v.typ, w.typ, p) {
return false
}
}
}
case *Signature:
- // Two function types are identical if they have the same number of parameters
- // and result values, corresponding parameter and result types are identical,
- // and either both functions are variadic or neither is. Parameter and result
- // names are not required to match.
- // Generic functions must also have matching type parameter lists, but for the
- // parameter names.
- if y, ok := y.(*Signature); ok {
- return x.variadic == y.variadic &&
- identicalTParams(x.tparams, y.tparams, cmpTags, p) &&
- identical(x.params, y.params, cmpTags, p) &&
- identical(x.results, y.results, cmpTags, p)
+ y, _ := y.(*Signature)
+ if y == nil {
+ return false
}
- case *Union:
- // Two union types are identical if they contain the same terms.
- // The set (list) of types in a union type consists of unique
- // types - each type appears exactly once. Thus, two union types
- // must contain the same number of types to have chance of
- // being equal.
- if y, ok := y.(*Union); ok && x.NumTerms() == y.NumTerms() {
- // Every type in x.types must be in y.types.
- // Quadratic algorithm, but probably good enough for now.
- // TODO(gri) we need a fast quick type ID/hash for all types.
- L:
- for i, xt := range x.types {
- for j, yt := range y.types {
- if Identical(xt, yt) && x.tilde[i] == y.tilde[j] {
- continue L // x is in y.types
- }
+ // Two function types are identical if they have the same number of
+ // parameters and result values, corresponding parameter and result types
+ // are identical, and either both functions are variadic or neither is.
+ // Parameter and result names are not required to match, and type
+ // parameters are considered identical modulo renaming.
+
+ if x.TypeParams().Len() != y.TypeParams().Len() {
+ return false
+ }
+
+ // In the case of generic signatures, we will substitute in yparams and
+ // yresults.
+ yparams := y.params
+ yresults := y.results
+
+ if x.TypeParams().Len() > 0 {
+ // We must ignore type parameter names when comparing x and y. The
+ // easiest way to do this is to substitute x's type parameters for y's.
+ xtparams := x.TypeParams().list()
+ ytparams := y.TypeParams().list()
+
+ var targs []Type
+ for i := range xtparams {
+ targs = append(targs, x.TypeParams().At(i))
+ }
+ smap := makeSubstMap(ytparams, targs)
+
+ var check *Checker // ok to call subst on a nil *Checker
+ ctxt := NewContext() // need a non-nil Context for the substitution below
+
+ // Constraints must be pair-wise identical, after substitution.
+ for i, xtparam := range xtparams {
+ ybound := check.subst(nopos, ytparams[i].bound, smap, nil, ctxt)
+ if !c.identical(xtparam.bound, ybound, p) {
+ return false
}
- return false // x is not in y.types
}
- return true
+
+ yparams = check.subst(nopos, y.params, smap, nil, ctxt).(*Tuple)
+ yresults = check.subst(nopos, y.results, smap, nil, ctxt).(*Tuple)
+ }
+
+ return x.variadic == y.variadic &&
+ c.identical(x.params, yparams, p) &&
+ c.identical(x.results, yresults, p)
+
+ case *Union:
+ if y, _ := y.(*Union); y != nil {
+ // TODO(rfindley): can this be reached during type checking? If so,
+ // consider passing a type set map.
+ unionSets := make(map[*Union]*_TypeSet)
+ xset := computeUnionTypeSet(nil, unionSets, nopos, x)
+ yset := computeUnionTypeSet(nil, unionSets, nopos, y)
+ return xset.terms.equal(yset.terms)
}
case *Interface:
if y, ok := y.(*Interface); ok {
xset := x.typeSet()
yset := y.typeSet()
- if !Identical(xset.types, yset.types) {
+ if xset.comparable != yset.comparable {
+ return false
+ }
+ if !xset.terms.equal(yset.terms) {
return false
}
a := xset.methods
}
for i, f := range a {
g := b[i]
- if f.Id() != g.Id() || !identical(f.typ, g.typ, cmpTags, q) {
+ if f.Id() != g.Id() || !c.identical(f.typ, g.typ, q) {
return false
}
}
case *Map:
// Two map types are identical if they have identical key and value types.
if y, ok := y.(*Map); ok {
- return identical(x.key, y.key, cmpTags, p) && identical(x.elem, y.elem, cmpTags, p)
+ return c.identical(x.key, y.key, p) && c.identical(x.elem, y.elem, p)
}
case *Chan:
// Two channel types are identical if they have identical value types
// and the same direction.
if y, ok := y.(*Chan); ok {
- return x.dir == y.dir && identical(x.elem, y.elem, cmpTags, p)
+ return x.dir == y.dir && c.identical(x.elem, y.elem, p)
}
case *Named:
// Two named types are identical if their type names originate
- // in the same type declaration.
- if y, ok := y.(*Named); ok {
- // 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
+ // 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
+ }
+ for i, xarg := range xargs {
+ if !Identical(xarg, yargs[i]) {
+ return false
+ }
+ }
+ return identicalOrigin(x, y)
}
case *TypeParam:
// nothing to do (x and y being equal is caught in the very beginning of this function)
- // case *instance:
- // unreachable since types are expanded
-
- case *top:
- // Either both types are theTop in which case the initial x == y check
- // will have caught them. Otherwise they are not identical.
-
case nil:
// avoid a crash in case of nil type
return false
}
-func identicalTParams(x, y []*TypeName, cmpTags bool, p *ifacePair) bool {
- if len(x) != len(y) {
+// 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.
+func identicalInstance(xorig Type, xargs []Type, yorig Type, yargs []Type) bool {
+ if len(xargs) != len(yargs) {
return false
}
- for i, x := range x {
- y := y[i]
- if !identical(x.typ.(*TypeParam).bound, y.typ.(*TypeParam).bound, cmpTags, p) {
+
+ for i, xa := range xargs {
+ if !Identical(xa, yargs[i]) {
return false
}
}
- return true
+
+ return Identical(xorig, yorig)
}
// Default returns the default "typed" type for an "untyped" type;
// it returns the incoming type for all other types. The default type
// for untyped nil is untyped nil.
-//
-func Default(typ Type) Type {
- if t, ok := typ.(*Basic); ok {
+func Default(t Type) Type {
+ if t, ok := _Unalias(t).(*Basic); ok {
switch t.kind {
case UntypedBool:
return Typ[Bool]
return Typ[String]
}
}
- return typ
+ 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
}