diff --git a/src/go/types/interface.go b/src/go/types/interface.go
index d27f8cfd4d..e9970ba101 100644
--- a/src/go/types/interface.go
+++ b/src/go/types/interface.go
@@ -105,7 +105,7 @@ func (t *Interface) Empty() bool { return t.typeSet().IsAll() }
 func (t *Interface) IsComparable() bool { return t.typeSet().IsComparable() }
 
 // IsConstraint reports whether interface t is not just a method set.
-func (t *Interface) IsConstraint() bool { return !t.typeSet().IsMethodSet() }
+func (t *Interface) IsConstraint() bool { return t.typeSet().IsConstraint() }
 
 // Complete computes the interface's type set. It must be called by users of
 // NewInterfaceType and NewInterface after the interface's embedded types are
diff --git a/src/go/types/typeset.go b/src/go/types/typeset.go
index fd9df4c010..293b6d0d44 100644
--- a/src/go/types/typeset.go
+++ b/src/go/types/typeset.go
@@ -28,10 +28,8 @@ func (s *_TypeSet) IsEmpty() bool { return s.terms.isEmpty() }
 // IsAll reports whether type set s is the set of all types (corresponding to the empty interface).
 func (s *_TypeSet) IsAll() bool { return !s.comparable && len(s.methods) == 0 && s.terms.isAll() }
 
-// TODO(gri) IsMethodSet is not a great name for this predicate. Find a better one.
-
-// IsMethodSet reports whether the type set s is described by a single set of methods.
-func (s *_TypeSet) IsMethodSet() bool { return !s.comparable && s.terms.isAll() }
+// IsConstraint reports whether type set s is not just a set of methods.
+func (s *_TypeSet) IsConstraint() bool { return s.comparable || !s.terms.isAll() }
 
 // IsComparable reports whether each type in the set is comparable.
 func (s *_TypeSet) IsComparable() bool {
diff --git a/src/go/types/typexpr.go b/src/go/types/typexpr.go
index 5a67982030..a126241afa 100644
--- a/src/go/types/typexpr.go
+++ b/src/go/types/typexpr.go
@@ -149,7 +149,7 @@ func (check *Checker) ordinaryType(pos positioner, typ Type) {
 	check.later(func() {
 		if t := asInterface(typ); t != nil {
 			tset := computeInterfaceTypeSet(check, pos.Pos(), t) // TODO(gri) is this the correct position?
-			if !tset.IsMethodSet() {
+			if tset.IsConstraint() {
 				if tset.comparable {
 					check.softErrorf(pos, _Todo, "interface is (or embeds) comparable")
 				} else {