feat: support embedded generic interfaces

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)
+}

mockgen/generic_notgo118.go

@@ -18,6 +18,7 @@
 package main
 
 import (
+	"fmt"
 	"go/ast"
 
 	"github.com/golang/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)
+}

mockgen/internal/tests/generics/external.go

@@ -1,6 +1,8 @@
 package generics
 
 import (
+	"context"
+
 	"github.com/golang/mock/mockgen/internal/tests/generics/other"
 	"golang.org/x/exp/constraints"
 )
@@ -19,3 +21,50 @@ type ExternalConstraint[I constraints.Integer, F constraints.Float] interface {
 	Nine(Iface[I])
 	Ten(*I)
 }
+
+type EmbeddingIface[T constraints.Integer, R constraints.Float] interface {
+	other.Twenty[T, StructType, R, other.Five]
+	TwentyTwo[StructType]
+	other.TwentyThree[TwentyTwo[R], TwentyTwo[T]]
+	TwentyFour[other.StructType]
+	Foo() error
+	ExternalConstraint[T, R]
+}
+
+type TwentyOne[T any] interface {
+	TwentyOne() T
+}
+
+type TwentyFour[T other.StructType] interface {
+	TwentyFour() T
+}
+
+type Clonable[T any] interface {
+	Clone() T
+}
+
+type Finder[T Clonable[T]] interface {
+	Find(ctx context.Context) ([]T, error)
+}
+
+type UpdateNotifier[T any] interface {
+	NotifyC(ctx context.Context) <-chan []T
+
+	Refresh(ctx context.Context)
+}
+
+type EmbeddedW[W StructType] interface {
+	EmbeddedY[W]
+}
+
+type EmbeddedX[X StructType] interface {
+	EmbeddedY[X]
+}
+
+type EmbeddedY[Y StructType] interface {
+	EmbeddedZ[Y]
+}
+
+type EmbeddedZ[Z any] interface {
+	EmbeddedZ(Z)
+}

mockgen/internal/tests/generics/generics.go

@@ -25,6 +25,7 @@ type Bar[T any, R any] interface {
 	Seventeen() (*Foo[other.Three, other.Four], error)
 	Eighteen() (Iface[*other.Five], error)
 	Nineteen() AliasType
+	other.Twenty[any, any, any, *other.Four]
 }
 
 type Foo[T any, R any] struct{}
@@ -38,3 +39,7 @@ type StructType struct{}
 type StructType2 struct{}
 
 type AliasType Baz[other.Three]
+
+type TwentyTwo[T any] interface {
+	TwentyTwo() T
+}

mockgen/internal/tests/generics/other/other.go

@@ -9,3 +9,13 @@ type Three struct{}
 type Four struct{}
 
 type Five interface{}
+
+type Twenty[R, S, T any, Z any] interface {
+	Twenty(S, R) (T, Z)
+}
+
+type TwentyThree[U, V any] interface {
+	TwentyThree(U, V) StructType
+}
+
+type StructType struct{}

mockgen/internal/tests/generics/source/assert_test.go

@@ -0,0 +1,12 @@
+package source
+
+import (
+	"testing"
+
+	"github.com/golang/mock/mockgen/internal/tests/generics"
+)
+
+func TestAssert(t *testing.T) {
+	var x MockEmbeddingIface[int, float64]
+	var _ generics.EmbeddingIface[int, float64] = &x
+}