diff --git a/go.mod b/go.mod
index ccc412f..46b7097 100644
--- a/go.mod
+++ b/go.mod
@@ -3,12 +3,11 @@ module go.uber.org/mock
 go 1.18
 
 require (
-	golang.org/x/mod v0.5.1
-	golang.org/x/tools v0.1.8
+	golang.org/x/mod v0.11.0
+	golang.org/x/tools v0.2.0
 )
 
 require (
-	github.com/yuin/goldmark v1.4.1 // indirect
-	golang.org/x/sys v0.0.0-20211019181941-9d821ace8654 // indirect
-	golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 // indirect
+	github.com/yuin/goldmark v1.4.13 // indirect
+	golang.org/x/sys v0.1.0 // indirect
 )
diff --git a/go.sum b/go.sum
index 6255813..38c7646 100644
--- a/go.sum
+++ b/go.sum
@@ -1,10 +1,8 @@
-github.com/yuin/goldmark v1.4.1 h1:/vn0k+RBvwlxEmP5E7SZMqNxPhfMVFEJiykr15/0XKM=
-github.com/yuin/goldmark v1.4.1/go.mod h1:mwnBkeHKe2W/ZEtQ+71ViKU8L12m81fl3OWwC1Zlc8k=
-golang.org/x/mod v0.5.1 h1:OJxoQ/rynoF0dcCdI7cLPktw/hR2cueqYfjm43oqK38=
-golang.org/x/mod v0.5.1/go.mod h1:5OXOZSfqPIIbmVBIIKWRFfZjPR0E5r58TLhUjH0a2Ro=
-golang.org/x/sys v0.0.0-20211019181941-9d821ace8654 h1:id054HUawV2/6IGm2IV8KZQjqtwAOo2CYlOToYqa0d0=
-golang.org/x/sys v0.0.0-20211019181941-9d821ace8654/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/tools v0.1.8 h1:P1HhGGuLW4aAclzjtmJdf0mJOjVUZUzOTqkAkWL+l6w=
-golang.org/x/tools v0.1.8/go.mod h1:nABZi5QlRsZVlzPpHl034qft6wpY4eDcsTt5AaioBiU=
-golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 h1:go1bK/D/BFZV2I8cIQd1NKEZ+0owSTG1fDTci4IqFcE=
-golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+github.com/yuin/goldmark v1.4.13 h1:fVcFKWvrslecOb/tg+Cc05dkeYx540o0FuFt3nUVDoE=
+github.com/yuin/goldmark v1.4.13/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=
+golang.org/x/mod v0.11.0 h1:bUO06HqtnRcc/7l71XBe4WcqTZ+3AH1J59zWDDwLKgU=
+golang.org/x/mod v0.11.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
+golang.org/x/sys v0.1.0 h1:kunALQeHf1/185U1i0GOB/fy1IPRDDpuoOOqRReG57U=
+golang.org/x/sys v0.1.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/tools v0.2.0 h1:G6AHpWxTMGY1KyEYoAQ5WTtIekUUvDNjan3ugu60JvE=
+golang.org/x/tools v0.2.0/go.mod h1:y4OqIKeOV/fWJetJ8bXPU1sEVniLMIyDAZWeHdV+NTA=
diff --git a/mockgen/generic_go118.go b/mockgen/generic_go118.go
index 917a15e..3b8ba6b 100644
--- a/mockgen/generic_go118.go
+++ b/mockgen/generic_go118.go
@@ -11,6 +11,7 @@
 package main
 
 import (
+	"fmt"
 	"go/ast"
 	"strings"
 
@@ -24,7 +25,7 @@ func getTypeSpecTypeParams(ts *ast.TypeSpec) []*ast.Field {
 	return ts.TypeParams.List
 }
 
-func (p *fileParser) parseGenericType(pkg string, typ ast.Expr, tps map[string]bool) (model.Type, error) {
+func (p *fileParser) parseGenericType(pkg string, typ ast.Expr, tps map[string]model.Type) (model.Type, error) {
 	switch v := typ.(type) {
 	case *ast.IndexExpr:
 		m, err := p.parseType(pkg, v.X, tps)
@@ -86,3 +87,30 @@ func getIdentTypeParams(decl interface{}) string {
 	sb.WriteString("]")
 	return sb.String()
 }
+
+func (p *fileParser) parseGenericMethod(field *ast.Field, it *namedInterface, iface *model.Interface, pkg string, tps map[string]model.Type) ([]*model.Method, error) {
+	var indices []ast.Expr
+	var typ ast.Expr
+	switch v := field.Type.(type) {
+	case *ast.IndexExpr:
+		indices = []ast.Expr{v.Index}
+		typ = v.X
+	case *ast.IndexListExpr:
+		indices = v.Indices
+		typ = v.X
+	default:
+		return nil, fmt.Errorf("don't know how to mock method of type %T", field.Type)
+	}
+
+	nf := &ast.Field{
+		Doc:     field.Comment,
+		Names:   field.Names,
+		Type:    typ,
+		Tag:     field.Tag,
+		Comment: field.Comment,
+	}
+
+	it.embeddedInstTypeParams = indices
+
+	return p.parseMethod(nf, it, iface, pkg, tps)
+}
diff --git a/mockgen/generic_notgo118.go b/mockgen/generic_notgo118.go
index b608438..b991b64 100644
--- a/mockgen/generic_notgo118.go
+++ b/mockgen/generic_notgo118.go
@@ -18,6 +18,7 @@
 package main
 
 import (
+	"fmt"
 	"go/ast"
 
 	"go.uber.org/mock/mockgen/model"
@@ -27,10 +28,14 @@ func getTypeSpecTypeParams(ts *ast.TypeSpec) []*ast.Field {
 	return nil
 }
 
-func (p *fileParser) parseGenericType(pkg string, typ ast.Expr, tps map[string]bool) (model.Type, error) {
+func (p *fileParser) parseGenericType(pkg string, typ ast.Expr, tps map[string]model.Type) (model.Type, error) {
 	return nil, nil
 }
 
 func getIdentTypeParams(decl interface{}) string {
 	return ""
 }
+
+func (p *fileParser) parseGenericMethod(field *ast.Field, it *namedInterface, iface *model.Interface, pkg string, tps map[string]model.Type) ([]*model.Method, error) {
+	return nil, fmt.Errorf("don't know how to mock method of type %T", field.Type)
+}
diff --git a/mockgen/internal/tests/generics/external.go b/mockgen/internal/tests/generics/external.go
index 68b2d4b..a12c39f 100644
--- a/mockgen/internal/tests/generics/external.go
+++ b/mockgen/internal/tests/generics/external.go
@@ -1,13 +1,16 @@
 package generics
 
 import (
+	"context"
+	"io"
+
 	"go.uber.org/mock/mockgen/internal/tests/generics/other"
 	"golang.org/x/exp/constraints"
 )
 
-//go:generate mockgen --source=external.go --destination=source/mock_external_test.go --package source
+//go:generate mockgen --source=external.go --destination=source/mock_external_mock.go --package source
 
-type ExternalConstraint[I constraints.Integer, F constraints.Float] interface {
+type ExternalConstraint[I constraints.Integer, F any] interface {
 	One(string) string
 	Two(I) string
 	Three(I) F
@@ -18,4 +21,23 @@ type ExternalConstraint[I constraints.Integer, F constraints.Float] interface {
 	Eight(F) other.Two[I, F]
 	Nine(Iface[I])
 	Ten(*I)
+	Eleven() map[string]I
+	Twelve(ctx context.Context) <-chan []I
+	Thirteen(...I) *F
+}
+
+type EmbeddingIface[T constraints.Integer, R constraints.Float] interface {
+	io.Reader
+	Generator[R]
+	Earth[Generator[T]]
+	other.Either[R, StructType, other.Five, Generator[T]]
+	ExternalConstraint[T, R]
+}
+
+type Generator[T any] interface {
+	Generate() T
+}
+
+type Group[T Generator[any]] interface {
+	Join(ctx context.Context) []T
 }
diff --git a/mockgen/internal/tests/generics/generics.go b/mockgen/internal/tests/generics/generics.go
index 647a6fc..5ee5692 100644
--- a/mockgen/internal/tests/generics/generics.go
+++ b/mockgen/internal/tests/generics/generics.go
@@ -1,8 +1,11 @@
 package generics
 
-import "go.uber.org/mock/mockgen/internal/tests/generics/other"
+import (
+	"go.uber.org/mock/mockgen/internal/tests/generics/other"
+	"golang.org/x/exp/constraints"
+)
 
-//go:generate mockgen --source=generics.go --destination=source/mock_generics_test.go --package source
+//go:generate mockgen --source=generics.go --destination=source/mock_generics_mock.go --package source
 ////go:generate mockgen --destination=reflect/mock_test.go --package reflect . Bar,Bar2
 
 type Bar[T any, R any] interface {
@@ -38,3 +41,19 @@ type StructType struct{}
 type StructType2 struct{}
 
 type AliasType Baz[other.Three]
+
+type Universe[T constraints.Signed] interface {
+	MilkyWay[T]
+}
+
+type MilkyWay[R constraints.Integer] interface {
+	SolarSystem[R]
+}
+
+type SolarSystem[T constraints.Ordered] interface {
+	Earth[T]
+}
+
+type Earth[R any] interface {
+	Water(R) []R
+}
diff --git a/mockgen/internal/tests/generics/go.mod b/mockgen/internal/tests/generics/go.mod
index 7eb82e1..f29c15e 100644
--- a/mockgen/internal/tests/generics/go.mod
+++ b/mockgen/internal/tests/generics/go.mod
@@ -1,10 +1,10 @@
-module github.com/golang/mock/mockgen/internal/tests/generics
+module go.uber.org/mock/mockgen/internal/tests/generics
 
 go 1.18
 
 require (
-	github.com/golang/mock v1.6.0
+	go.uber.org/mock v1.6.0
 	golang.org/x/exp v0.0.0-20220428152302-39d4317da171
 )
 
-replace github.com/golang/mock => ../../../..
+replace go.uber.org/mock => ../../../..
diff --git a/mockgen/internal/tests/generics/go.sum b/mockgen/internal/tests/generics/go.sum
index c6f4464..698ce9b 100644
--- a/mockgen/internal/tests/generics/go.sum
+++ b/mockgen/internal/tests/generics/go.sum
@@ -1,26 +1,2 @@
-github.com/yuin/goldmark v1.4.1/go.mod h1:mwnBkeHKe2W/ZEtQ+71ViKU8L12m81fl3OWwC1Zlc8k=
-golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
-golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
 golang.org/x/exp v0.0.0-20220428152302-39d4317da171 h1:TfdoLivD44QwvssI9Sv1xwa5DcL5XQr4au4sZ2F2NV4=
 golang.org/x/exp v0.0.0-20220428152302-39d4317da171/go.mod h1:lgLbSvA5ygNOMpwM/9anMpWVlVJ7Z+cHWq/eFuinpGE=
-golang.org/x/mod v0.5.1/go.mod h1:5OXOZSfqPIIbmVBIIKWRFfZjPR0E5r58TLhUjH0a2Ro=
-golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
-golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
-golang.org/x/net v0.0.0-20211015210444-4f30a5c0130f/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
-golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
-golang.org/x/sync v0.0.0-20210220032951-036812b2e83c/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
-golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
-golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20210423082822-04245dca01da/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20211019181941-9d821ace8654/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
-golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
-golang.org/x/text v0.3.6/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
-golang.org/x/text v0.3.7/go.mod h1:u+2+/6zg+i71rQMx5EYifcz6MCKuco9NR6JIITiCfzQ=
-golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
-golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
-golang.org/x/tools v0.1.8/go.mod h1:nABZi5QlRsZVlzPpHl034qft6wpY4eDcsTt5AaioBiU=
-golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
-golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
-golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
diff --git a/mockgen/internal/tests/generics/other/other.go b/mockgen/internal/tests/generics/other/other.go
index 9265422..6de7fe1 100644
--- a/mockgen/internal/tests/generics/other/other.go
+++ b/mockgen/internal/tests/generics/other/other.go
@@ -9,3 +9,10 @@ type Three struct{}
 type Four struct{}
 
 type Five interface{}
+
+type Either[T, R, K, V any] interface {
+	First() T
+	Second() R
+	Third() K
+	Fourth() V
+}
diff --git a/mockgen/internal/tests/generics/source/mock_external_mock.go b/mockgen/internal/tests/generics/source/mock_external_mock.go
new file mode 100644
index 0000000..62f42d5
--- /dev/null
+++ b/mockgen/internal/tests/generics/source/mock_external_mock.go
@@ -0,0 +1,598 @@
+// Code generated by MockGen. DO NOT EDIT.
+// Source: external.go
+
+// Package source is a generated GoMock package.
+package source
+
+import (
+	context "context"
+	reflect "reflect"
+
+	gomock "go.uber.org/mock/gomock"
+	generics "go.uber.org/mock/mockgen/internal/tests/generics"
+	other "go.uber.org/mock/mockgen/internal/tests/generics/other"
+	constraints "golang.org/x/exp/constraints"
+)
+
+// MockExternalConstraint is a mock of ExternalConstraint interface.
+type MockExternalConstraint[I constraints.Integer, F any] struct {
+	ctrl     *gomock.Controller
+	recorder *MockExternalConstraintMockRecorder[I, F]
+}
+
+// MockExternalConstraintMockRecorder is the mock recorder for MockExternalConstraint.
+type MockExternalConstraintMockRecorder[I constraints.Integer, F any] struct {
+	mock *MockExternalConstraint[I, F]
+}
+
+// NewMockExternalConstraint creates a new mock instance.
+func NewMockExternalConstraint[I constraints.Integer, F any](ctrl *gomock.Controller) *MockExternalConstraint[I, F] {
+	mock := &MockExternalConstraint[I, F]{ctrl: ctrl}
+	mock.recorder = &MockExternalConstraintMockRecorder[I, F]{mock}
+	return mock
+}
+
+// EXPECT returns an object that allows the caller to indicate expected use.
+func (m *MockExternalConstraint[I, F]) EXPECT() *MockExternalConstraintMockRecorder[I, F] {
+	return m.recorder
+}
+
+// Eight mocks base method.
+func (m *MockExternalConstraint[I, F]) Eight(arg0 F) other.Two[I, F] {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "Eight", arg0)
+	ret0, _ := ret[0].(other.Two[I, F])
+	return ret0
+}
+
+// Eight indicates an expected call of Eight.
+func (mr *MockExternalConstraintMockRecorder[I, F]) Eight(arg0 interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Eight", reflect.TypeOf((*MockExternalConstraint[I, F])(nil).Eight), arg0)
+}
+
+// Eleven mocks base method.
+func (m *MockExternalConstraint[I, F]) Eleven() map[string]I {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "Eleven")
+	ret0, _ := ret[0].(map[string]I)
+	return ret0
+}
+
+// Eleven indicates an expected call of Eleven.
+func (mr *MockExternalConstraintMockRecorder[I, F]) Eleven() *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Eleven", reflect.TypeOf((*MockExternalConstraint[I, F])(nil).Eleven))
+}
+
+// Five mocks base method.
+func (m *MockExternalConstraint[I, F]) Five(arg0 I) generics.Baz[F] {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "Five", arg0)
+	ret0, _ := ret[0].(generics.Baz[F])
+	return ret0
+}
+
+// Five indicates an expected call of Five.
+func (mr *MockExternalConstraintMockRecorder[I, F]) Five(arg0 interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Five", reflect.TypeOf((*MockExternalConstraint[I, F])(nil).Five), arg0)
+}
+
+// Four mocks base method.
+func (m *MockExternalConstraint[I, F]) Four(arg0 I) generics.Foo[I, F] {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "Four", arg0)
+	ret0, _ := ret[0].(generics.Foo[I, F])
+	return ret0
+}
+
+// Four indicates an expected call of Four.
+func (mr *MockExternalConstraintMockRecorder[I, F]) Four(arg0 interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Four", reflect.TypeOf((*MockExternalConstraint[I, F])(nil).Four), arg0)
+}
+
+// Nine mocks base method.
+func (m *MockExternalConstraint[I, F]) Nine(arg0 generics.Iface[I]) {
+	m.ctrl.T.Helper()
+	m.ctrl.Call(m, "Nine", arg0)
+}
+
+// Nine indicates an expected call of Nine.
+func (mr *MockExternalConstraintMockRecorder[I, F]) Nine(arg0 interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Nine", reflect.TypeOf((*MockExternalConstraint[I, F])(nil).Nine), arg0)
+}
+
+// One mocks base method.
+func (m *MockExternalConstraint[I, F]) One(arg0 string) string {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "One", arg0)
+	ret0, _ := ret[0].(string)
+	return ret0
+}
+
+// One indicates an expected call of One.
+func (mr *MockExternalConstraintMockRecorder[I, F]) One(arg0 interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "One", reflect.TypeOf((*MockExternalConstraint[I, F])(nil).One), arg0)
+}
+
+// Seven mocks base method.
+func (m *MockExternalConstraint[I, F]) Seven(arg0 I) other.One[I] {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "Seven", arg0)
+	ret0, _ := ret[0].(other.One[I])
+	return ret0
+}
+
+// Seven indicates an expected call of Seven.
+func (mr *MockExternalConstraintMockRecorder[I, F]) Seven(arg0 interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Seven", reflect.TypeOf((*MockExternalConstraint[I, F])(nil).Seven), arg0)
+}
+
+// Six mocks base method.
+func (m *MockExternalConstraint[I, F]) Six(arg0 I) *generics.Baz[F] {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "Six", arg0)
+	ret0, _ := ret[0].(*generics.Baz[F])
+	return ret0
+}
+
+// Six indicates an expected call of Six.
+func (mr *MockExternalConstraintMockRecorder[I, F]) Six(arg0 interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Six", reflect.TypeOf((*MockExternalConstraint[I, F])(nil).Six), arg0)
+}
+
+// Ten mocks base method.
+func (m *MockExternalConstraint[I, F]) Ten(arg0 *I) {
+	m.ctrl.T.Helper()
+	m.ctrl.Call(m, "Ten", arg0)
+}
+
+// Ten indicates an expected call of Ten.
+func (mr *MockExternalConstraintMockRecorder[I, F]) Ten(arg0 interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Ten", reflect.TypeOf((*MockExternalConstraint[I, F])(nil).Ten), arg0)
+}
+
+// Thirteen mocks base method.
+func (m *MockExternalConstraint[I, F]) Thirteen(arg0 ...I) *F {
+	m.ctrl.T.Helper()
+	varargs := []interface{}{}
+	for _, a := range arg0 {
+		varargs = append(varargs, a)
+	}
+	ret := m.ctrl.Call(m, "Thirteen", varargs...)
+	ret0, _ := ret[0].(*F)
+	return ret0
+}
+
+// Thirteen indicates an expected call of Thirteen.
+func (mr *MockExternalConstraintMockRecorder[I, F]) Thirteen(arg0 ...interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Thirteen", reflect.TypeOf((*MockExternalConstraint[I, F])(nil).Thirteen), arg0...)
+}
+
+// Three mocks base method.
+func (m *MockExternalConstraint[I, F]) Three(arg0 I) F {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "Three", arg0)
+	ret0, _ := ret[0].(F)
+	return ret0
+}
+
+// Three indicates an expected call of Three.
+func (mr *MockExternalConstraintMockRecorder[I, F]) Three(arg0 interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Three", reflect.TypeOf((*MockExternalConstraint[I, F])(nil).Three), arg0)
+}
+
+// Twelve mocks base method.
+func (m *MockExternalConstraint[I, F]) Twelve(ctx context.Context) <-chan []I {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "Twelve", ctx)
+	ret0, _ := ret[0].(<-chan []I)
+	return ret0
+}
+
+// Twelve indicates an expected call of Twelve.
+func (mr *MockExternalConstraintMockRecorder[I, F]) Twelve(ctx interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Twelve", reflect.TypeOf((*MockExternalConstraint[I, F])(nil).Twelve), ctx)
+}
+
+// Two mocks base method.
+func (m *MockExternalConstraint[I, F]) Two(arg0 I) string {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "Two", arg0)
+	ret0, _ := ret[0].(string)
+	return ret0
+}
+
+// Two indicates an expected call of Two.
+func (mr *MockExternalConstraintMockRecorder[I, F]) Two(arg0 interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Two", reflect.TypeOf((*MockExternalConstraint[I, F])(nil).Two), arg0)
+}
+
+// MockEmbeddingIface is a mock of EmbeddingIface interface.
+type MockEmbeddingIface[T constraints.Integer, R constraints.Float] struct {
+	ctrl     *gomock.Controller
+	recorder *MockEmbeddingIfaceMockRecorder[T, R]
+}
+
+// MockEmbeddingIfaceMockRecorder is the mock recorder for MockEmbeddingIface.
+type MockEmbeddingIfaceMockRecorder[T constraints.Integer, R constraints.Float] struct {
+	mock *MockEmbeddingIface[T, R]
+}
+
+// NewMockEmbeddingIface creates a new mock instance.
+func NewMockEmbeddingIface[T constraints.Integer, R constraints.Float](ctrl *gomock.Controller) *MockEmbeddingIface[T, R] {
+	mock := &MockEmbeddingIface[T, R]{ctrl: ctrl}
+	mock.recorder = &MockEmbeddingIfaceMockRecorder[T, R]{mock}
+	return mock
+}
+
+// EXPECT returns an object that allows the caller to indicate expected use.
+func (m *MockEmbeddingIface[T, R]) EXPECT() *MockEmbeddingIfaceMockRecorder[T, R] {
+	return m.recorder
+}
+
+// Eight mocks base method.
+func (m *MockEmbeddingIface[T, R]) Eight(arg0 R) other.Two[T, R] {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "Eight", arg0)
+	ret0, _ := ret[0].(other.Two[T, R])
+	return ret0
+}
+
+// Eight indicates an expected call of Eight.
+func (mr *MockEmbeddingIfaceMockRecorder[T, R]) Eight(arg0 interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Eight", reflect.TypeOf((*MockEmbeddingIface[T, R])(nil).Eight), arg0)
+}
+
+// Eleven mocks base method.
+func (m *MockEmbeddingIface[T, R]) Eleven() map[string]T {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "Eleven")
+	ret0, _ := ret[0].(map[string]T)
+	return ret0
+}
+
+// Eleven indicates an expected call of Eleven.
+func (mr *MockEmbeddingIfaceMockRecorder[T, R]) Eleven() *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Eleven", reflect.TypeOf((*MockEmbeddingIface[T, R])(nil).Eleven))
+}
+
+// First mocks base method.
+func (m *MockEmbeddingIface[T, R]) First() R {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "First")
+	ret0, _ := ret[0].(R)
+	return ret0
+}
+
+// First indicates an expected call of First.
+func (mr *MockEmbeddingIfaceMockRecorder[T, R]) First() *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "First", reflect.TypeOf((*MockEmbeddingIface[T, R])(nil).First))
+}
+
+// Five mocks base method.
+func (m *MockEmbeddingIface[T, R]) Five(arg0 T) generics.Baz[R] {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "Five", arg0)
+	ret0, _ := ret[0].(generics.Baz[R])
+	return ret0
+}
+
+// Five indicates an expected call of Five.
+func (mr *MockEmbeddingIfaceMockRecorder[T, R]) Five(arg0 interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Five", reflect.TypeOf((*MockEmbeddingIface[T, R])(nil).Five), arg0)
+}
+
+// Four mocks base method.
+func (m *MockEmbeddingIface[T, R]) Four(arg0 T) generics.Foo[T, R] {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "Four", arg0)
+	ret0, _ := ret[0].(generics.Foo[T, R])
+	return ret0
+}
+
+// Four indicates an expected call of Four.
+func (mr *MockEmbeddingIfaceMockRecorder[T, R]) Four(arg0 interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Four", reflect.TypeOf((*MockEmbeddingIface[T, R])(nil).Four), arg0)
+}
+
+// Fourth mocks base method.
+func (m *MockEmbeddingIface[T, R]) Fourth() generics.Generator[T] {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "Fourth")
+	ret0, _ := ret[0].(generics.Generator[T])
+	return ret0
+}
+
+// Fourth indicates an expected call of Fourth.
+func (mr *MockEmbeddingIfaceMockRecorder[T, R]) Fourth() *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Fourth", reflect.TypeOf((*MockEmbeddingIface[T, R])(nil).Fourth))
+}
+
+// Generate mocks base method.
+func (m *MockEmbeddingIface[T, R]) Generate() R {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "Generate")
+	ret0, _ := ret[0].(R)
+	return ret0
+}
+
+// Generate indicates an expected call of Generate.
+func (mr *MockEmbeddingIfaceMockRecorder[T, R]) Generate() *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Generate", reflect.TypeOf((*MockEmbeddingIface[T, R])(nil).Generate))
+}
+
+// Nine mocks base method.
+func (m *MockEmbeddingIface[T, R]) Nine(arg0 generics.Iface[T]) {
+	m.ctrl.T.Helper()
+	m.ctrl.Call(m, "Nine", arg0)
+}
+
+// Nine indicates an expected call of Nine.
+func (mr *MockEmbeddingIfaceMockRecorder[T, R]) Nine(arg0 interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Nine", reflect.TypeOf((*MockEmbeddingIface[T, R])(nil).Nine), arg0)
+}
+
+// One mocks base method.
+func (m *MockEmbeddingIface[T, R]) One(arg0 string) string {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "One", arg0)
+	ret0, _ := ret[0].(string)
+	return ret0
+}
+
+// One indicates an expected call of One.
+func (mr *MockEmbeddingIfaceMockRecorder[T, R]) One(arg0 interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "One", reflect.TypeOf((*MockEmbeddingIface[T, R])(nil).One), arg0)
+}
+
+// Read mocks base method.
+func (m *MockEmbeddingIface[T, R]) Read(p []byte) (int, error) {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "Read", p)
+	ret0, _ := ret[0].(int)
+	ret1, _ := ret[1].(error)
+	return ret0, ret1
+}
+
+// Read indicates an expected call of Read.
+func (mr *MockEmbeddingIfaceMockRecorder[T, R]) Read(p interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Read", reflect.TypeOf((*MockEmbeddingIface[T, R])(nil).Read), p)
+}
+
+// Second mocks base method.
+func (m *MockEmbeddingIface[T, R]) Second() generics.StructType {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "Second")
+	ret0, _ := ret[0].(generics.StructType)
+	return ret0
+}
+
+// Second indicates an expected call of Second.
+func (mr *MockEmbeddingIfaceMockRecorder[T, R]) Second() *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Second", reflect.TypeOf((*MockEmbeddingIface[T, R])(nil).Second))
+}
+
+// Seven mocks base method.
+func (m *MockEmbeddingIface[T, R]) Seven(arg0 T) other.One[T] {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "Seven", arg0)
+	ret0, _ := ret[0].(other.One[T])
+	return ret0
+}
+
+// Seven indicates an expected call of Seven.
+func (mr *MockEmbeddingIfaceMockRecorder[T, R]) Seven(arg0 interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Seven", reflect.TypeOf((*MockEmbeddingIface[T, R])(nil).Seven), arg0)
+}
+
+// Six mocks base method.
+func (m *MockEmbeddingIface[T, R]) Six(arg0 T) *generics.Baz[R] {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "Six", arg0)
+	ret0, _ := ret[0].(*generics.Baz[R])
+	return ret0
+}
+
+// Six indicates an expected call of Six.
+func (mr *MockEmbeddingIfaceMockRecorder[T, R]) Six(arg0 interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Six", reflect.TypeOf((*MockEmbeddingIface[T, R])(nil).Six), arg0)
+}
+
+// Ten mocks base method.
+func (m *MockEmbeddingIface[T, R]) Ten(arg0 *T) {
+	m.ctrl.T.Helper()
+	m.ctrl.Call(m, "Ten", arg0)
+}
+
+// Ten indicates an expected call of Ten.
+func (mr *MockEmbeddingIfaceMockRecorder[T, R]) Ten(arg0 interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Ten", reflect.TypeOf((*MockEmbeddingIface[T, R])(nil).Ten), arg0)
+}
+
+// Third mocks base method.
+func (m *MockEmbeddingIface[T, R]) Third() other.Five {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "Third")
+	ret0, _ := ret[0].(other.Five)
+	return ret0
+}
+
+// Third indicates an expected call of Third.
+func (mr *MockEmbeddingIfaceMockRecorder[T, R]) Third() *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Third", reflect.TypeOf((*MockEmbeddingIface[T, R])(nil).Third))
+}
+
+// Thirteen mocks base method.
+func (m *MockEmbeddingIface[T, R]) Thirteen(arg0 ...T) *R {
+	m.ctrl.T.Helper()
+	varargs := []interface{}{}
+	for _, a := range arg0 {
+		varargs = append(varargs, a)
+	}
+	ret := m.ctrl.Call(m, "Thirteen", varargs...)
+	ret0, _ := ret[0].(*R)
+	return ret0
+}
+
+// Thirteen indicates an expected call of Thirteen.
+func (mr *MockEmbeddingIfaceMockRecorder[T, R]) Thirteen(arg0 ...interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Thirteen", reflect.TypeOf((*MockEmbeddingIface[T, R])(nil).Thirteen), arg0...)
+}
+
+// Three mocks base method.
+func (m *MockEmbeddingIface[T, R]) Three(arg0 T) R {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "Three", arg0)
+	ret0, _ := ret[0].(R)
+	return ret0
+}
+
+// Three indicates an expected call of Three.
+func (mr *MockEmbeddingIfaceMockRecorder[T, R]) Three(arg0 interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Three", reflect.TypeOf((*MockEmbeddingIface[T, R])(nil).Three), arg0)
+}
+
+// Twelve mocks base method.
+func (m *MockEmbeddingIface[T, R]) Twelve(ctx context.Context) <-chan []T {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "Twelve", ctx)
+	ret0, _ := ret[0].(<-chan []T)
+	return ret0
+}
+
+// Twelve indicates an expected call of Twelve.
+func (mr *MockEmbeddingIfaceMockRecorder[T, R]) Twelve(ctx interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Twelve", reflect.TypeOf((*MockEmbeddingIface[T, R])(nil).Twelve), ctx)
+}
+
+// Two mocks base method.
+func (m *MockEmbeddingIface[T, R]) Two(arg0 T) string {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "Two", arg0)
+	ret0, _ := ret[0].(string)
+	return ret0
+}
+
+// Two indicates an expected call of Two.
+func (mr *MockEmbeddingIfaceMockRecorder[T, R]) Two(arg0 interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Two", reflect.TypeOf((*MockEmbeddingIface[T, R])(nil).Two), arg0)
+}
+
+// Water mocks base method.
+func (m *MockEmbeddingIface[T, R]) Water(arg0 generics.Generator[T]) []generics.Generator[T] {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "Water", arg0)
+	ret0, _ := ret[0].([]generics.Generator[T])
+	return ret0
+}
+
+// Water indicates an expected call of Water.
+func (mr *MockEmbeddingIfaceMockRecorder[T, R]) Water(arg0 interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Water", reflect.TypeOf((*MockEmbeddingIface[T, R])(nil).Water), arg0)
+}
+
+// MockGenerator is a mock of Generator interface.
+type MockGenerator[T any] struct {
+	ctrl     *gomock.Controller
+	recorder *MockGeneratorMockRecorder[T]
+}
+
+// MockGeneratorMockRecorder is the mock recorder for MockGenerator.
+type MockGeneratorMockRecorder[T any] struct {
+	mock *MockGenerator[T]
+}
+
+// NewMockGenerator creates a new mock instance.
+func NewMockGenerator[T any](ctrl *gomock.Controller) *MockGenerator[T] {
+	mock := &MockGenerator[T]{ctrl: ctrl}
+	mock.recorder = &MockGeneratorMockRecorder[T]{mock}
+	return mock
+}
+
+// EXPECT returns an object that allows the caller to indicate expected use.
+func (m *MockGenerator[T]) EXPECT() *MockGeneratorMockRecorder[T] {
+	return m.recorder
+}
+
+// Generate mocks base method.
+func (m *MockGenerator[T]) Generate() T {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "Generate")
+	ret0, _ := ret[0].(T)
+	return ret0
+}
+
+// Generate indicates an expected call of Generate.
+func (mr *MockGeneratorMockRecorder[T]) Generate() *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Generate", reflect.TypeOf((*MockGenerator[T])(nil).Generate))
+}
+
+// MockGroup is a mock of Group interface.
+type MockGroup[T generics.Generator[any]] struct {
+	ctrl     *gomock.Controller
+	recorder *MockGroupMockRecorder[T]
+}
+
+// MockGroupMockRecorder is the mock recorder for MockGroup.
+type MockGroupMockRecorder[T generics.Generator[any]] struct {
+	mock *MockGroup[T]
+}
+
+// NewMockGroup creates a new mock instance.
+func NewMockGroup[T generics.Generator[any]](ctrl *gomock.Controller) *MockGroup[T] {
+	mock := &MockGroup[T]{ctrl: ctrl}
+	mock.recorder = &MockGroupMockRecorder[T]{mock}
+	return mock
+}
+
+// EXPECT returns an object that allows the caller to indicate expected use.
+func (m *MockGroup[T]) EXPECT() *MockGroupMockRecorder[T] {
+	return m.recorder
+}
+
+// Join mocks base method.
+func (m *MockGroup[T]) Join(ctx context.Context) []T {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "Join", ctx)
+	ret0, _ := ret[0].([]T)
+	return ret0
+}
+
+// Join indicates an expected call of Join.
+func (mr *MockGroupMockRecorder[T]) Join(ctx interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Join", reflect.TypeOf((*MockGroup[T])(nil).Join), ctx)
+}
diff --git a/mockgen/internal/tests/generics/source/mock_external_test.go b/mockgen/internal/tests/generics/source/mock_external_test.go
index 32a876b..c345164 100644
--- a/mockgen/internal/tests/generics/source/mock_external_test.go
+++ b/mockgen/internal/tests/generics/source/mock_external_test.go
@@ -1,173 +1,41 @@
-// Code generated by MockGen. DO NOT EDIT.
-// Source: external.go
-
-// Package source is a generated GoMock package.
 package source
 
 import (
-	reflect "reflect"
+	"context"
+	"testing"
 
-	gomock "go.uber.org/mock/gomock"
-	generics "go.uber.org/mock/mockgen/internal/tests/generics"
-	other "go.uber.org/mock/mockgen/internal/tests/generics/other"
-	constraints "golang.org/x/exp/constraints"
+	"go.uber.org/mock/gomock"
+	"go.uber.org/mock/mockgen/internal/tests/generics"
 )
 
-// MockExternalConstraint is a mock of ExternalConstraint interface.
-type MockExternalConstraint[I constraints.Integer, F constraints.Float] struct {
-	ctrl     *gomock.Controller
-	recorder *MockExternalConstraintMockRecorder[I, F]
-}
-
-// MockExternalConstraintMockRecorder is the mock recorder for MockExternalConstraint.
-type MockExternalConstraintMockRecorder[I constraints.Integer, F constraints.Float] struct {
-	mock *MockExternalConstraint[I, F]
-}
-
-// NewMockExternalConstraint creates a new mock instance.
-func NewMockExternalConstraint[I constraints.Integer, F constraints.Float](ctrl *gomock.Controller) *MockExternalConstraint[I, F] {
-	mock := &MockExternalConstraint[I, F]{ctrl: ctrl}
-	mock.recorder = &MockExternalConstraintMockRecorder[I, F]{mock}
-	return mock
-}
-
-// EXPECT returns an object that allows the caller to indicate expected use.
-func (m *MockExternalConstraint[I, F]) EXPECT() *MockExternalConstraintMockRecorder[I, F] {
-	return m.recorder
-}
-
-// Eight mocks base method.
-func (m *MockExternalConstraint[I, F]) Eight(arg0 F) other.Two[I, F] {
-	m.ctrl.T.Helper()
-	ret := m.ctrl.Call(m, "Eight", arg0)
-	ret0, _ := ret[0].(other.Two[I, F])
-	return ret0
-}
-
-// Eight indicates an expected call of Eight.
-func (mr *MockExternalConstraintMockRecorder[I, F]) Eight(arg0 interface{}) *gomock.Call {
-	mr.mock.ctrl.T.Helper()
-	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Eight", reflect.TypeOf((*MockExternalConstraint[I, F])(nil).Eight), arg0)
-}
-
-// Five mocks base method.
-func (m *MockExternalConstraint[I, F]) Five(arg0 I) generics.Baz[F] {
-	m.ctrl.T.Helper()
-	ret := m.ctrl.Call(m, "Five", arg0)
-	ret0, _ := ret[0].(generics.Baz[F])
-	return ret0
-}
-
-// Five indicates an expected call of Five.
-func (mr *MockExternalConstraintMockRecorder[I, F]) Five(arg0 interface{}) *gomock.Call {
-	mr.mock.ctrl.T.Helper()
-	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Five", reflect.TypeOf((*MockExternalConstraint[I, F])(nil).Five), arg0)
-}
-
-// Four mocks base method.
-func (m *MockExternalConstraint[I, F]) Four(arg0 I) generics.Foo[I, F] {
-	m.ctrl.T.Helper()
-	ret := m.ctrl.Call(m, "Four", arg0)
-	ret0, _ := ret[0].(generics.Foo[I, F])
-	return ret0
-}
-
-// Four indicates an expected call of Four.
-func (mr *MockExternalConstraintMockRecorder[I, F]) Four(arg0 interface{}) *gomock.Call {
-	mr.mock.ctrl.T.Helper()
-	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Four", reflect.TypeOf((*MockExternalConstraint[I, F])(nil).Four), arg0)
-}
-
-// Nine mocks base method.
-func (m *MockExternalConstraint[I, F]) Nine(arg0 generics.Iface[I]) {
-	m.ctrl.T.Helper()
-	m.ctrl.Call(m, "Nine", arg0)
-}
-
-// Nine indicates an expected call of Nine.
-func (mr *MockExternalConstraintMockRecorder[I, F]) Nine(arg0 interface{}) *gomock.Call {
-	mr.mock.ctrl.T.Helper()
-	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Nine", reflect.TypeOf((*MockExternalConstraint[I, F])(nil).Nine), arg0)
-}
-
-// One mocks base method.
-func (m *MockExternalConstraint[I, F]) One(arg0 string) string {
-	m.ctrl.T.Helper()
-	ret := m.ctrl.Call(m, "One", arg0)
-	ret0, _ := ret[0].(string)
-	return ret0
-}
-
-// One indicates an expected call of One.
-func (mr *MockExternalConstraintMockRecorder[I, F]) One(arg0 interface{}) *gomock.Call {
-	mr.mock.ctrl.T.Helper()
-	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "One", reflect.TypeOf((*MockExternalConstraint[I, F])(nil).One), arg0)
-}
-
-// Seven mocks base method.
-func (m *MockExternalConstraint[I, F]) Seven(arg0 I) other.One[I] {
-	m.ctrl.T.Helper()
-	ret := m.ctrl.Call(m, "Seven", arg0)
-	ret0, _ := ret[0].(other.One[I])
-	return ret0
-}
-
-// Seven indicates an expected call of Seven.
-func (mr *MockExternalConstraintMockRecorder[I, F]) Seven(arg0 interface{}) *gomock.Call {
-	mr.mock.ctrl.T.Helper()
-	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Seven", reflect.TypeOf((*MockExternalConstraint[I, F])(nil).Seven), arg0)
-}
-
-// Six mocks base method.
-func (m *MockExternalConstraint[I, F]) Six(arg0 I) *generics.Baz[F] {
-	m.ctrl.T.Helper()
-	ret := m.ctrl.Call(m, "Six", arg0)
-	ret0, _ := ret[0].(*generics.Baz[F])
-	return ret0
-}
-
-// Six indicates an expected call of Six.
-func (mr *MockExternalConstraintMockRecorder[I, F]) Six(arg0 interface{}) *gomock.Call {
-	mr.mock.ctrl.T.Helper()
-	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Six", reflect.TypeOf((*MockExternalConstraint[I, F])(nil).Six), arg0)
-}
+func TestMockEmbeddingIface_One(t *testing.T) {
+	ctrl := gomock.NewController(t)
+	defer ctrl.Finish()
 
-// Ten mocks base method.
-func (m *MockExternalConstraint[I, F]) Ten(arg0 *I) {
-	m.ctrl.T.Helper()
-	m.ctrl.Call(m, "Ten", arg0)
+	m := NewMockEmbeddingIface[int, float64](ctrl)
+	m.EXPECT().One("foo").Return("bar")
+	if v := m.One("foo"); v != "bar" {
+		t.Errorf("One() = %v, want %v", v, "bar")
+	}
 }
 
-// Ten indicates an expected call of Ten.
-func (mr *MockExternalConstraintMockRecorder[I, F]) Ten(arg0 interface{}) *gomock.Call {
-	mr.mock.ctrl.T.Helper()
-	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Ten", reflect.TypeOf((*MockExternalConstraint[I, F])(nil).Ten), arg0)
-}
+func TestMockUniverse_Water(t *testing.T) {
+	ctrl := gomock.NewController(t)
+	defer ctrl.Finish()
 
-// Three mocks base method.
-func (m *MockExternalConstraint[I, F]) Three(arg0 I) F {
-	m.ctrl.T.Helper()
-	ret := m.ctrl.Call(m, "Three", arg0)
-	ret0, _ := ret[0].(F)
-	return ret0
+	m := NewMockUniverse[int](ctrl)
+	m.EXPECT().Water(1024)
+	m.Water(1024)
 }
 
-// Three indicates an expected call of Three.
-func (mr *MockExternalConstraintMockRecorder[I, F]) Three(arg0 interface{}) *gomock.Call {
-	mr.mock.ctrl.T.Helper()
-	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Three", reflect.TypeOf((*MockExternalConstraint[I, F])(nil).Three), arg0)
-}
-
-// Two mocks base method.
-func (m *MockExternalConstraint[I, F]) Two(arg0 I) string {
-	m.ctrl.T.Helper()
-	ret := m.ctrl.Call(m, "Two", arg0)
-	ret0, _ := ret[0].(string)
-	return ret0
-}
+func TestNewMockGroup_Join(t *testing.T) {
+	ctrl := gomock.NewController(t)
+	defer ctrl.Finish()
 
-// Two indicates an expected call of Two.
-func (mr *MockExternalConstraintMockRecorder[I, F]) Two(arg0 interface{}) *gomock.Call {
-	mr.mock.ctrl.T.Helper()
-	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Two", reflect.TypeOf((*MockExternalConstraint[I, F])(nil).Two), arg0)
+	m := NewMockGroup[generics.Generator[any]](ctrl)
+	ctx := context.TODO()
+	m.EXPECT().Join(ctx).Return(nil)
+	if v := m.Join(ctx); v != nil {
+		t.Errorf("Join() = %v, want %v", v, nil)
+	}
 }
diff --git a/mockgen/internal/tests/generics/source/mock_generics_test.go b/mockgen/internal/tests/generics/source/mock_generics_mock.go
similarity index 69%
rename from mockgen/internal/tests/generics/source/mock_generics_test.go
rename to mockgen/internal/tests/generics/source/mock_generics_mock.go
index ad34340..db27915 100644
--- a/mockgen/internal/tests/generics/source/mock_generics_test.go
+++ b/mockgen/internal/tests/generics/source/mock_generics_mock.go
@@ -10,6 +10,7 @@ import (
 	gomock "go.uber.org/mock/gomock"
 	generics "go.uber.org/mock/mockgen/internal/tests/generics"
 	other "go.uber.org/mock/mockgen/internal/tests/generics/other"
+	constraints "golang.org/x/exp/constraints"
 )
 
 // MockBar is a mock of Bar interface.
@@ -327,3 +328,151 @@ func NewMockIface[T any](ctrl *gomock.Controller) *MockIface[T] {
 func (m *MockIface[T]) EXPECT() *MockIfaceMockRecorder[T] {
 	return m.recorder
 }
+
+// MockUniverse is a mock of Universe interface.
+type MockUniverse[T constraints.Signed] struct {
+	ctrl     *gomock.Controller
+	recorder *MockUniverseMockRecorder[T]
+}
+
+// MockUniverseMockRecorder is the mock recorder for MockUniverse.
+type MockUniverseMockRecorder[T constraints.Signed] struct {
+	mock *MockUniverse[T]
+}
+
+// NewMockUniverse creates a new mock instance.
+func NewMockUniverse[T constraints.Signed](ctrl *gomock.Controller) *MockUniverse[T] {
+	mock := &MockUniverse[T]{ctrl: ctrl}
+	mock.recorder = &MockUniverseMockRecorder[T]{mock}
+	return mock
+}
+
+// EXPECT returns an object that allows the caller to indicate expected use.
+func (m *MockUniverse[T]) EXPECT() *MockUniverseMockRecorder[T] {
+	return m.recorder
+}
+
+// Water mocks base method.
+func (m *MockUniverse[T]) Water(arg0 T) []T {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "Water", arg0)
+	ret0, _ := ret[0].([]T)
+	return ret0
+}
+
+// Water indicates an expected call of Water.
+func (mr *MockUniverseMockRecorder[T]) Water(arg0 interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Water", reflect.TypeOf((*MockUniverse[T])(nil).Water), arg0)
+}
+
+// MockMilkyWay is a mock of MilkyWay interface.
+type MockMilkyWay[R constraints.Integer] struct {
+	ctrl     *gomock.Controller
+	recorder *MockMilkyWayMockRecorder[R]
+}
+
+// MockMilkyWayMockRecorder is the mock recorder for MockMilkyWay.
+type MockMilkyWayMockRecorder[R constraints.Integer] struct {
+	mock *MockMilkyWay[R]
+}
+
+// NewMockMilkyWay creates a new mock instance.
+func NewMockMilkyWay[R constraints.Integer](ctrl *gomock.Controller) *MockMilkyWay[R] {
+	mock := &MockMilkyWay[R]{ctrl: ctrl}
+	mock.recorder = &MockMilkyWayMockRecorder[R]{mock}
+	return mock
+}
+
+// EXPECT returns an object that allows the caller to indicate expected use.
+func (m *MockMilkyWay[R]) EXPECT() *MockMilkyWayMockRecorder[R] {
+	return m.recorder
+}
+
+// Water mocks base method.
+func (m *MockMilkyWay[R]) Water(arg0 R) []R {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "Water", arg0)
+	ret0, _ := ret[0].([]R)
+	return ret0
+}
+
+// Water indicates an expected call of Water.
+func (mr *MockMilkyWayMockRecorder[R]) Water(arg0 interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Water", reflect.TypeOf((*MockMilkyWay[R])(nil).Water), arg0)
+}
+
+// MockSolarSystem is a mock of SolarSystem interface.
+type MockSolarSystem[T constraints.Ordered] struct {
+	ctrl     *gomock.Controller
+	recorder *MockSolarSystemMockRecorder[T]
+}
+
+// MockSolarSystemMockRecorder is the mock recorder for MockSolarSystem.
+type MockSolarSystemMockRecorder[T constraints.Ordered] struct {
+	mock *MockSolarSystem[T]
+}
+
+// NewMockSolarSystem creates a new mock instance.
+func NewMockSolarSystem[T constraints.Ordered](ctrl *gomock.Controller) *MockSolarSystem[T] {
+	mock := &MockSolarSystem[T]{ctrl: ctrl}
+	mock.recorder = &MockSolarSystemMockRecorder[T]{mock}
+	return mock
+}
+
+// EXPECT returns an object that allows the caller to indicate expected use.
+func (m *MockSolarSystem[T]) EXPECT() *MockSolarSystemMockRecorder[T] {
+	return m.recorder
+}
+
+// Water mocks base method.
+func (m *MockSolarSystem[T]) Water(arg0 T) []T {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "Water", arg0)
+	ret0, _ := ret[0].([]T)
+	return ret0
+}
+
+// Water indicates an expected call of Water.
+func (mr *MockSolarSystemMockRecorder[T]) Water(arg0 interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Water", reflect.TypeOf((*MockSolarSystem[T])(nil).Water), arg0)
+}
+
+// MockEarth is a mock of Earth interface.
+type MockEarth[R any] struct {
+	ctrl     *gomock.Controller
+	recorder *MockEarthMockRecorder[R]
+}
+
+// MockEarthMockRecorder is the mock recorder for MockEarth.
+type MockEarthMockRecorder[R any] struct {
+	mock *MockEarth[R]
+}
+
+// NewMockEarth creates a new mock instance.
+func NewMockEarth[R any](ctrl *gomock.Controller) *MockEarth[R] {
+	mock := &MockEarth[R]{ctrl: ctrl}
+	mock.recorder = &MockEarthMockRecorder[R]{mock}
+	return mock
+}
+
+// EXPECT returns an object that allows the caller to indicate expected use.
+func (m *MockEarth[R]) EXPECT() *MockEarthMockRecorder[R] {
+	return m.recorder
+}
+
+// Water mocks base method.
+func (m *MockEarth[R]) Water(arg0 R) []R {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "Water", arg0)
+	ret0, _ := ret[0].([]R)
+	return ret0
+}
+
+// Water indicates an expected call of Water.
+func (mr *MockEarthMockRecorder[R]) Water(arg0 interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Water", reflect.TypeOf((*MockEarth[R])(nil).Water), arg0)
+}
diff --git a/mockgen/parse.go b/mockgen/parse.go
index aab9066..a397922 100644
--- a/mockgen/parse.go
+++ b/mockgen/parse.go
@@ -274,20 +274,77 @@ func (p *fileParser) parsePackage(path string) (*fileParser, error) {
 	return newP, nil
 }
 
+func (p *fileParser) constructInstParams(pkg string, params []*ast.Field, instParams []model.Type, embeddedInstParams []ast.Expr, tps map[string]model.Type) ([]model.Type, error) {
+	pm := make(map[string]int)
+	var i int
+	for _, v := range params {
+		for _, n := range v.Names {
+			pm[n.Name] = i
+			instParams = append(instParams, model.PredeclaredType(n.Name))
+			i++
+		}
+	}
+
+	var runtimeInstParams []model.Type
+	for _, instParam := range embeddedInstParams {
+		switch t := instParam.(type) {
+		case *ast.Ident:
+			if idx, ok := pm[t.Name]; ok {
+				runtimeInstParams = append(runtimeInstParams, instParams[idx])
+				continue
+			}
+		}
+		modelType, err := p.parseType(pkg, instParam, tps)
+		if err != nil {
+			return nil, err
+		}
+		runtimeInstParams = append(runtimeInstParams, modelType)
+	}
+
+	return runtimeInstParams, nil
+}
+
+func (p *fileParser) constructTps(it *namedInterface) (tps map[string]model.Type) {
+	tps = make(map[string]model.Type)
+	n := 0
+	for _, tp := range it.typeParams {
+		for _, tm := range tp.Names {
+			tps[tm.Name] = nil
+			if len(it.instTypes) != 0 {
+				tps[tm.Name] = it.instTypes[n]
+				n++
+			}
+		}
+	}
+	return tps
+}
+
+// parseInterface loads interface specified by pkg and name, parses it and returns
+// a new model with the parsed.
 func (p *fileParser) parseInterface(name, pkg string, it *namedInterface) (*model.Interface, error) {
 	iface := &model.Interface{Name: name}
-	tps := make(map[string]bool)
-
+	tps := p.constructTps(it)
 	tp, err := p.parseFieldList(pkg, it.typeParams, tps)
 	if err != nil {
 		return nil, fmt.Errorf("unable to parse interface type parameters: %v", name)
 	}
+
 	iface.TypeParams = tp
-	for _, v := range tp {
-		tps[v.Name] = true
+	for _, field := range it.it.Methods.List {
+		var methods []*model.Method
+		if methods, err = p.parseMethod(field, it, iface, pkg, tps); err != nil {
+			return nil, err
+		}
+		for _, m := range methods {
+			iface.AddMethod(m)
+		}
 	}
+	return iface, nil
+}
 
-	for _, field := range it.it.Methods.List {
+func (p *fileParser) parseMethod(field *ast.Field, it *namedInterface, iface *model.Interface, pkg string, tps map[string]model.Type) ([]*model.Method, error) {
+	// {} for git diff
+	{
 		switch v := field.Type.(type) {
 		case *ast.FuncType:
 			if nn := len(field.Names); nn != 1 {
@@ -301,7 +358,7 @@ func (p *fileParser) parseInterface(name, pkg string, it *namedInterface) (*mode
 			if err != nil {
 				return nil, err
 			}
-			iface.AddMethod(m)
+			return []*model.Method{m}, nil
 		case *ast.Ident:
 			// Embedded interface in this package.
 			embeddedIfaceType := p.auxInterfaces.Get(pkg, v.String())
@@ -312,10 +369,15 @@ func (p *fileParser) parseInterface(name, pkg string, it *namedInterface) (*mode
 			var embeddedIface *model.Interface
 			if embeddedIfaceType != nil {
 				var err error
+				embeddedIfaceType.instTypes, err = p.constructInstParams(pkg, it.typeParams, it.instTypes, it.embeddedInstTypeParams, tps)
+				if err != nil {
+					return nil, err
+				}
 				embeddedIface, err = p.parseInterface(v.String(), pkg, embeddedIfaceType)
 				if err != nil {
 					return nil, err
 				}
+
 			} else {
 				// This is built-in error interface.
 				if v.String() == model.ErrorInterface.Name {
@@ -330,16 +392,17 @@ func (p *fileParser) parseInterface(name, pkg string, it *namedInterface) (*mode
 						return nil, p.errorf(v.Pos(), "unknown embedded interface %s.%s", pkg, v.String())
 					}
 
+					embeddedIfaceType.instTypes, err = p.constructInstParams(pkg, it.typeParams, it.instTypes, it.embeddedInstTypeParams, tps)
+					if err != nil {
+						return nil, err
+					}
 					embeddedIface, err = ip.parseInterface(v.String(), pkg, embeddedIfaceType)
 					if err != nil {
 						return nil, err
 					}
 				}
 			}
-			// Copy the methods.
-			for _, m := range embeddedIface.Methods {
-				iface.AddMethod(m)
-			}
+			return embeddedIface.Methods, nil
 		case *ast.SelectorExpr:
 			// Embedded interface in another package.
 			filePkg, sel := v.X.(*ast.Ident).String(), v.Sel.String()
@@ -352,6 +415,10 @@ func (p *fileParser) parseInterface(name, pkg string, it *namedInterface) (*mode
 			var err error
 			embeddedIfaceType := p.auxInterfaces.Get(filePkg, sel)
 			if embeddedIfaceType != nil {
+				embeddedIfaceType.instTypes, err = p.constructInstParams(pkg, it.typeParams, it.instTypes, it.embeddedInstTypeParams, tps)
+				if err != nil {
+					return nil, err
+				}
 				embeddedIface, err = p.parseInterface(sel, filePkg, embeddedIfaceType)
 				if err != nil {
 					return nil, err
@@ -373,24 +440,25 @@ func (p *fileParser) parseInterface(name, pkg string, it *namedInterface) (*mode
 				if embeddedIfaceType = parser.importedInterfaces.Get(path, sel); embeddedIfaceType == nil {
 					return nil, p.errorf(v.Pos(), "unknown embedded interface %s.%s", path, sel)
 				}
+
+				embeddedIfaceType.instTypes, err = p.constructInstParams(pkg, it.typeParams, it.instTypes, it.embeddedInstTypeParams, tps)
+				if err != nil {
+					return nil, err
+				}
 				embeddedIface, err = parser.parseInterface(sel, path, embeddedIfaceType)
 				if err != nil {
 					return nil, err
 				}
 			}
-			// Copy the methods.
 			// TODO: apply shadowing rules.
-			for _, m := range embeddedIface.Methods {
-				iface.AddMethod(m)
-			}
+			return embeddedIface.Methods, nil
 		default:
-			return nil, fmt.Errorf("don't know how to mock method of type %T", field.Type)
+			return p.parseGenericMethod(field, it, iface, pkg, tps)
 		}
 	}
-	return iface, nil
 }
 
-func (p *fileParser) parseFunc(pkg string, f *ast.FuncType, tps map[string]bool) (inParam []*model.Parameter, variadic *model.Parameter, outParam []*model.Parameter, err error) {
+func (p *fileParser) parseFunc(pkg string, f *ast.FuncType, tps map[string]model.Type) (inParam []*model.Parameter, variadic *model.Parameter, outParam []*model.Parameter, err error) {
 	if f.Params != nil {
 		regParams := f.Params.List
 		if isVariadic(f) {
@@ -417,7 +485,7 @@ func (p *fileParser) parseFunc(pkg string, f *ast.FuncType, tps map[string]bool)
 	return
 }
 
-func (p *fileParser) parseFieldList(pkg string, fields []*ast.Field, tps map[string]bool) ([]*model.Parameter, error) {
+func (p *fileParser) parseFieldList(pkg string, fields []*ast.Field, tps map[string]model.Type) ([]*model.Parameter, error) {
 	nf := 0
 	for _, f := range fields {
 		nn := len(f.Names)
@@ -451,7 +519,7 @@ func (p *fileParser) parseFieldList(pkg string, fields []*ast.Field, tps map[str
 	return ps, nil
 }
 
-func (p *fileParser) parseType(pkg string, typ ast.Expr, tps map[string]bool) (model.Type, error) {
+func (p *fileParser) parseType(pkg string, typ ast.Expr, tps map[string]model.Type) (model.Type, error) {
 	switch v := typ.(type) {
 	case *ast.ArrayType:
 		ln := -1
@@ -493,7 +561,8 @@ func (p *fileParser) parseType(pkg string, typ ast.Expr, tps map[string]bool) (m
 		}
 		return &model.FuncType{In: in, Out: out, Variadic: variadic}, nil
 	case *ast.Ident:
-		if v.IsExported() && !tps[v.Name] {
+		it, ok := tps[v.Name]
+		if v.IsExported() && !ok {
 			// `pkg` may be an aliased imported pkg
 			// if so, patch the import w/ the fully qualified import
 			maybeImportedPkg, ok := p.imports[pkg]
@@ -503,7 +572,9 @@ func (p *fileParser) parseType(pkg string, typ ast.Expr, tps map[string]bool) (m
 			// assume type in this package
 			return &model.NamedType{Package: pkg, Type: v.Name}, nil
 		}
-
+		if ok && it != nil {
+			return it, nil
+		}
 		// assume predeclared type
 		return model.PredeclaredType(v.Name), nil
 	case *ast.InterfaceType:
@@ -657,9 +728,11 @@ func importsOfFile(file *ast.File) (normalImports map[string]importedPackage, do
 }
 
 type namedInterface struct {
-	name       *ast.Ident
-	it         *ast.InterfaceType
-	typeParams []*ast.Field
+	name                   *ast.Ident
+	it                     *ast.InterfaceType
+	typeParams             []*ast.Field
+	embeddedInstTypeParams []ast.Expr
+	instTypes              []model.Type
 }
 
 // Create an iterator over all interfaces in file.
@@ -681,7 +754,7 @@ func iterInterfaces(file *ast.File) <-chan *namedInterface {
 					continue
 				}
 
-				ch <- &namedInterface{ts.Name, it, getTypeSpecTypeParams(ts)}
+				ch <- &namedInterface{name: ts.Name, it: it, typeParams: getTypeSpecTypeParams(ts)}
 			}
 		}
 		close(ch)