// Implementation

// hasTerms reports whether the type set has specific type terms.
func (s *_TypeSet) hasTerms() bool { return !s.terms.isEmpty() && !s.terms.isAll() }

// subsetOf reports whether s1 ⊆ s2.
func (s1 *_TypeSet) subsetOf(s2 *_TypeSet) bool { return s1.terms.subsetOf(s2.terms) }

// TODO(gri) TypeSet.is and TypeSet.underIs should probably also go into termlist.go

// Implementation

// hasTerms reports whether the type set has specific type terms.
func (s *_TypeSet) hasTerms() bool { return !s.terms.isEmpty() && !s.terms.isAll() }

// subsetOf reports whether s1 ⊆ s2.
func (s1 *_TypeSet) subsetOf(s2 *_TypeSet) bool { return s1.terms.subsetOf(s2.terms) }

// TODO(gri) TypeSet.is and TypeSet.underIs should probably also go into termlist.go

	if !Ti.typeSet().hasTerms() {
		return checkComparability() // nothing to do
	}

	// If V is itself an interface, each of its possible types must be in the set
	// of T types (i.e., the V type set must be a subset of the T type set).
	// Interfaces V with empty type sets were already excluded above.
	if Vi != nil {
		if !Vi.typeSet().subsetOf(Ti.typeSet()) {
			// TODO(gri) report which type is missing

	if !Ti.typeSet().hasTerms() {
		return checkComparability() // nothing to do
	}

	// If V is itself an interface, each of its possible types must be in the set
	// of T types (i.e., the V type set must be a subset of the T type set).
	// Interfaces V with empty type sets were already excluded above.
	if Vi != nil {
		if !Vi.typeSet().subsetOf(Ti.typeSet()) {
			// TODO(gri) report which type is missing

plugins:
  social:
    cards_layout_dir: ../en/layouts
    cards_layout: custom
    cards_layout_options:
      logo: ../en/docs/img/icon-white.svg

func (t *TypeParam) is(f func(*term) bool) bool {
	return t.iface().typeSet().is(f)
}

// underIs calls f with the underlying types of the specific type terms
// of t's constraint and reports whether all calls to f returned true.
// If there are no specific terms, underIs returns the result of f(nil).
func (t *TypeParam) underIs(f func(Type) bool) bool {
	return t.iface().typeSet().underIs(f)

		}

	default:
		// For externally defined implementations of Type.
		// Note: In this case cycles won't be caught.
		w.string(t.String())
	}
}

// typeSet writes a canonical hash for an interface type set.
func (w *typeWriter) typeSet(s *_TypeSet) {
	assert(w.ctxt != nil)
	first := true
	for _, m := range s.methods {
		if !first {
			w.byte(';')
		}
		first = false
		w.string(m.name)

		}

	default:
		// For externally defined implementations of Type.
		// Note: In this case cycles won't be caught.
		w.string(t.String())
	}
}

// typeSet writes a canonical hash for an interface type set.
func (w *typeWriter) typeSet(s *_TypeSet) {
	assert(w.ctxt != nil)
	first := true
	for _, m := range s.methods {
		if !first {
			w.byte(';')
		}
		first = false
		w.string(m.name)

			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
}

func (t *TypeParam) is(f func(*term) bool) bool {
	return t.iface().typeSet().is(f)
}

// underIs calls f with the underlying types of the specific type terms
// of t's constraint and reports whether all calls to f returned true.
// If there are no specific terms, underIs returns the result of f(nil).
func (t *TypeParam) underIs(f func(Type) bool) bool {
	return t.iface().typeSet().underIs(f)