diff --git a/Gopkg.lock b/Gopkg.lock
index 34890156d5d..7399021ad65 100644
--- a/Gopkg.lock
+++ b/Gopkg.lock
@@ -26,7 +26,7 @@
   version = "v3.3.2"
 
 [[projects]]
-  digest = "1:f3df613325a793ffb3d0ce7644a3bb6f62db45ac744dafe20172fe999c61cdbf"
+  digest = "1:78907d832e27dbfc6e3fdfc52bd2e5e2e05c1d0e3789d4825b824489fbeab233"
   name = "github.com/gogo/protobuf"
   packages = [
     "io",
@@ -99,7 +99,7 @@
   version = "v1.0.0"
 
 [[projects]]
-  digest = "1:450b7623b185031f3a456801155c8320209f75d0d4c4e633c6b1e59d44d6e392"
+  digest = "1:27af6024faa3c28426a698b8c653be0fd908bc96e25b7d76f2192eb342427db6"
   name = "github.com/opentracing/opentracing-go"
   packages = [
     ".",
@@ -143,7 +143,7 @@
   revision = "ffb13db8def02f545acc58bd288ec6057c2bbfb9"
 
 [[projects]]
-  digest = "1:7e8d267900c7fa7f35129a2a37596e38ed0f11ca746d6d9ba727980ee138f9f6"
+  digest = "1:73697231b93fb74a73ebd8384b68b9a60c57ea6b13c56d2425414566a72c8e6d"
   name = "github.com/stretchr/testify"
   packages = [
     "assert",
@@ -171,7 +171,7 @@
 
 [[projects]]
   branch = "master"
-  digest = "1:7fa8a2105f0b0853395a85d3dd8ef1475c44919374c6496dba7b987586edaced"
+  digest = "1:3e2c3d0b8cb780a09467884bebc032c831ae273d1d993b8f55fa61084e37278c"
   name = "github.com/vektah/gqlparser"
   packages = [
     ".",
@@ -183,7 +183,7 @@
     "validator/rules",
   ]
   pruneopts = "UT"
-  revision = "f119686bf1d4d1a68c7ed6afe35f183625443c41"
+  revision = "91abf84889ffb5ab4537b0ae1b1670109a9fbc28"
 
 [[projects]]
   branch = "master"
@@ -195,7 +195,7 @@
 
 [[projects]]
   branch = "master"
-  digest = "1:3cbc05413b8aac22b1f6d4350ed696b5a83a8515a4136db8f1ec3a0aee3d76e1"
+  digest = "1:77fe642412bfed48743e2b75163e3ab5c430cfe22dd488788647b89b28794635"
   name = "golang.org/x/tools"
   packages = [
     "go/ast/astutil",
@@ -216,7 +216,7 @@
 
 [[projects]]
   branch = "master"
-  digest = "1:741ebea9214cc226789d3003baeca9b169e04b5b336fb1a3b2c16e75bd296bb5"
+  digest = "1:7ddb3a7b35cc853fe0db36a1b2473bdff03f28add7d28e4725e692603111266e"
   name = "sourcegraph.com/sourcegraph/appdash"
   packages = [
     ".",
@@ -232,7 +232,7 @@
 
 [[projects]]
   branch = "master"
-  digest = "1:8e0a2957fe342f22d70a543c3fcdf390f7627419c3d82d87ab4fd715a9ef5716"
+  digest = "1:be108b48d79c3b3c345811a57a47ee87fdbe895beb4bb56239da71d4943e5be7"
   name = "sourcegraph.com/sourcegraph/appdash-data"
   packages = ["."]
   pruneopts = "UT"
diff --git a/codegen/interface_build.go b/codegen/interface_build.go
index 92052ba6b99..9f4a4ff4d5c 100644
--- a/codegen/interface_build.go
+++ b/codegen/interface_build.go
@@ -1,7 +1,9 @@
 package codegen
 
 import (
+	"fmt"
 	"go/types"
+	"os"
 	"sort"
 
 	"github.com/vektah/gqlparser/ast"
@@ -49,5 +51,20 @@ func (cfg *Config) isValueReceiver(intf *NamedType, implementor *NamedType, prog
 		return true
 	}
 
-	return types.Implements(implementorType, interfaceType)
+	for i := 0; i < interfaceType.NumMethods(); i++ {
+		intfMethod := interfaceType.Method(i)
+
+		implMethod := findMethod(implementorType, intfMethod.Name())
+		if implMethod == nil {
+			fmt.Fprintf(os.Stderr, "missing method %s on %s\n", intfMethod.Name(), implementor.GoType)
+			return false
+		}
+
+		sig := implMethod.Type().(*types.Signature)
+		if _, isPtr := sig.Recv().Type().(*types.Pointer); isPtr {
+			return false
+		}
+	}
+
+	return true
 }
diff --git a/codegen/model.go b/codegen/model.go
index bcdc8703a6c..5ba50337e27 100644
--- a/codegen/model.go
+++ b/codegen/model.go
@@ -4,7 +4,6 @@ type Model struct {
 	*NamedType
 	Description string
 	Fields      []ModelField
-	Implements  []*NamedType
 }
 
 type ModelField struct {
diff --git a/codegen/models_build.go b/codegen/models_build.go
index bf0c9c9b8f1..9f98a07dd5d 100644
--- a/codegen/models_build.go
+++ b/codegen/models_build.go
@@ -54,9 +54,8 @@ func (cfg *Config) buildModels(types NamedTypes, prog *loader.Program, imports *
 
 func (cfg *Config) obj2Model(obj *Object) Model {
 	model := Model{
-		NamedType:  obj.NamedType,
-		Implements: obj.Implements,
-		Fields:     []ModelField{},
+		NamedType: obj.NamedType,
+		Fields:    []ModelField{},
 	}
 
 	model.GoType = ucFirst(obj.GQLType)
diff --git a/codegen/object.go b/codegen/object.go
index c037344fe65..0c9479b0ae5 100644
--- a/codegen/object.go
+++ b/codegen/object.go
@@ -24,7 +24,6 @@ type Object struct {
 
 	Fields             []Field
 	Satisfies          []string
-	Implements         []*NamedType
 	ResolverInterface  *Ref
 	Root               bool
 	DisableConcurrency bool
diff --git a/codegen/object_build.go b/codegen/object_build.go
index 9c9e548e41e..ee2b2f1c2b9 100644
--- a/codegen/object_build.go
+++ b/codegen/object_build.go
@@ -104,10 +104,6 @@ func (cfg *Config) buildObject(types NamedTypes, typ *ast.Definition, imports *I
 
 	obj.Satisfies = append(obj.Satisfies, typ.Interfaces...)
 
-	for _, intf := range cfg.schema.GetImplements(typ) {
-		obj.Implements = append(obj.Implements, types[intf.Name])
-	}
-
 	for _, field := range typ.Fields {
 		if typ == cfg.schema.Query && field.Name == "__type" {
 			obj.Fields = append(obj.Fields, Field{
diff --git a/codegen/templates/data.go b/codegen/templates/data.go
index d2f4e7312a6..5a15e9109b6 100644
--- a/codegen/templates/data.go
+++ b/codegen/templates/data.go
@@ -6,7 +6,7 @@ var data = map[string]string{
 	"generated.gotpl": "// Code generated by github.com/99designs/gqlgen, DO NOT EDIT.\n\npackage {{ .PackageName }}\n\nimport (\n{{- range $import := .Imports }}\n\t{{- $import.Write }}\n{{ end }}\n)\n\n// NewExecutableSchema creates an ExecutableSchema from the ResolverRoot interface.\nfunc NewExecutableSchema(cfg Config) graphql.ExecutableSchema {\n\treturn &executableSchema{\n\t\tresolvers: cfg.Resolvers,\n\t\tdirectives: cfg.Directives,\n\t\tcomplexity: cfg.Complexity,\n\t}\n}\n\ntype Config struct {\n\tResolvers  ResolverRoot\n\tDirectives DirectiveRoot\n\tComplexity ComplexityRoot\n}\n\ntype ResolverRoot interface {\n{{- range $object := .Objects -}}\n\t{{ if $object.HasResolvers -}}\n\t\t{{$object.GQLType}}() {{$object.GQLType}}Resolver\n\t{{ end }}\n{{- end }}\n}\n\ntype DirectiveRoot struct {\n{{ range $directive := .Directives }}\n\t{{ $directive.Declaration }}\n{{ end }}\n}\n\ntype ComplexityRoot struct {\n{{ range $object := .Objects }}\n\t{{ if not $object.IsReserved -}}\n\t\t{{ $object.GQLType|toCamel }} struct {\n\t\t{{ range $field := $object.Fields -}}\n\t\t\t{{ if not $field.IsReserved -}}\n\t\t\t\t{{ $field.GQLName|toCamel }} {{ $field.ComplexitySignature }}\n\t\t\t{{ end }}\n\t\t{{- end }}\n\t\t}\n\t{{- end }}\n{{ end }}\n}\n\n{{ range $object := .Objects -}}\n\t{{ if $object.HasResolvers }}\n\t\ttype {{$object.GQLType}}Resolver interface {\n\t\t{{ range $field := $object.Fields -}}\n\t\t\t{{ $field.ShortResolverDeclaration }}\n\t\t{{ end }}\n\t\t}\n\t{{- end }}\n{{- end }}\n\n{{ range $object := .Objects -}}\n\t{{ range $field := $object.Fields -}}\n\t\t{{ if $field.Args }}\n\t\t\tfunc {{ $field.ArgsFunc }}(rawArgs map[string]interface{}) (map[string]interface{}, error) {\n\t\t\t{{ template \"args.gotpl\" $field.Args }}\n\t\t\t}\n\t\t{{ end }}\n\t{{ end }}\n{{- end }}\n\n{{ range $directive := .Directives }}\n\t{{ if $directive.Args }}\n\t\tfunc {{ $directive.ArgsFunc }}(rawArgs map[string]interface{}) (map[string]interface{}, error) {\n\t\t{{ template \"args.gotpl\" $directive.Args }}\n\t\t}\n\t{{ end }}\n{{ end }}\n\ntype executableSchema struct {\n\tresolvers  ResolverRoot\n\tdirectives DirectiveRoot\n\tcomplexity ComplexityRoot\n}\n\nfunc (e *executableSchema) Schema() *ast.Schema {\n\treturn parsedSchema\n}\n\nfunc (e *executableSchema) Complexity(typeName, field string, childComplexity int, rawArgs map[string]interface{}) (int, bool) {\n\tswitch typeName + \".\" + field {\n\t{{ range $object := .Objects }}\n\t\t{{ if not $object.IsReserved }}\n\t\t\t{{ range $field := $object.Fields }}\n\t\t\t\t{{ if not $field.IsReserved }}\n\t\t\t\t\tcase \"{{$object.GQLType}}.{{$field.GQLName}}\":\n\t\t\t\t\t\tif e.complexity.{{$object.GQLType|toCamel}}.{{$field.GQLName|toCamel}} == nil {\n\t\t\t\t\t\t\tbreak\n\t\t\t\t\t\t}\n\t\t\t\t\t\t{{ if $field.Args }}\n\t\t\t\t\t\t\targs, err := {{ $field.ArgsFunc }}(rawArgs)\n\t\t\t\t\t\t\tif err != nil {\n\t\t\t\t\t\t\t\treturn 0, false\n\t\t\t\t\t\t\t}\n\t\t\t\t\t\t{{ end }}\n\t\t\t\t\t\treturn e.complexity.{{$object.GQLType|toCamel}}.{{$field.GQLName|toCamel}}(childComplexity{{if $field.Args}}, {{$field.ComplexityArgs}} {{end}}), true\n\t\t\t\t{{ end }}\n\t\t\t{{ end }}\n\t\t{{ end }}\n\t{{ end }}\n\t}\n\treturn 0, false\n}\n\nfunc (e *executableSchema) Query(ctx context.Context, op *ast.OperationDefinition) *graphql.Response {\n\t{{- if .QueryRoot }}\n\t\tec := executionContext{graphql.GetRequestContext(ctx), e}\n\n\t\tbuf := ec.RequestMiddleware(ctx, func(ctx context.Context) []byte {\n\t\t\tdata := ec._{{.QueryRoot.GQLType}}(ctx, op.SelectionSet)\n\t\t\tvar buf bytes.Buffer\n\t\t\tdata.MarshalGQL(&buf)\n\t\t\treturn buf.Bytes()\n\t\t})\n\n\t\treturn &graphql.Response{\n\t\t\tData:       buf,\n\t\t\tErrors:     ec.Errors,\n\t\t\tExtensions: ec.Extensions,\t\t}\n\t{{- else }}\n\t\treturn graphql.ErrorResponse(ctx, \"queries are not supported\")\n\t{{- end }}\n}\n\nfunc (e *executableSchema) Mutation(ctx context.Context, op *ast.OperationDefinition) *graphql.Response {\n\t{{- if .MutationRoot }}\n\t\tec := executionContext{graphql.GetRequestContext(ctx), e}\n\n\t\tbuf := ec.RequestMiddleware(ctx, func(ctx context.Context) []byte {\n\t\t\tdata := ec._{{.MutationRoot.GQLType}}(ctx, op.SelectionSet)\n\t\t\tvar buf bytes.Buffer\n\t\t\tdata.MarshalGQL(&buf)\n\t\t\treturn buf.Bytes()\n\t\t})\n\n\t\treturn &graphql.Response{\n\t\t\tData:       buf,\n\t\t\tErrors:     ec.Errors,\n\t\t\tExtensions: ec.Extensions,\n\t\t}\n\t{{- else }}\n\t\treturn graphql.ErrorResponse(ctx, \"mutations are not supported\")\n\t{{- end }}\n}\n\nfunc (e *executableSchema) Subscription(ctx context.Context, op *ast.OperationDefinition) func() *graphql.Response {\n\t{{- if .SubscriptionRoot }}\n\t\tec := executionContext{graphql.GetRequestContext(ctx), e}\n\n\t\tnext := ec._{{.SubscriptionRoot.GQLType}}(ctx, op.SelectionSet)\n\t\tif ec.Errors != nil {\n\t\t\treturn graphql.OneShot(&graphql.Response{Data: []byte(\"null\"), Errors: ec.Errors})\n\t\t}\n\n\t\tvar buf bytes.Buffer\n\t\treturn func() *graphql.Response {\n\t\t\tbuf := ec.RequestMiddleware(ctx, func(ctx context.Context) []byte {\n\t\t\t\tbuf.Reset()\n\t\t\t\tdata := next()\n\n\t\t\t\tif data == nil {\n\t\t\t\t\treturn nil\n\t\t\t\t}\n\t\t\t\tdata.MarshalGQL(&buf)\n\t\t\t\treturn buf.Bytes()\n\t\t\t})\n\n\t\t\tif buf == nil {\n\t\t\t\treturn nil\n\t\t\t}\n\n\t\t\treturn &graphql.Response{\n\t\t\t\tData:       buf,\n\t\t\t\tErrors:     ec.Errors,\n\t\t\t\tExtensions: ec.Extensions,\n\t\t\t}\n\t\t}\n\t{{- else }}\n\t\treturn graphql.OneShot(graphql.ErrorResponse(ctx, \"subscriptions are not supported\"))\n\t{{- end }}\n}\n\ntype executionContext struct {\n\t*graphql.RequestContext\n\t*executableSchema\n}\n\n{{- range $object := .Objects }}\n\t{{ template \"object.gotpl\" $object }}\n\n\t{{- range $field := $object.Fields }}\n\t\t{{ template \"field.gotpl\" $field }}\n\t{{ end }}\n{{- end}}\n\n{{- range $interface := .Interfaces }}\n\t{{ template \"interface.gotpl\" $interface }}\n{{- end }}\n\n{{- range $input := .Inputs }}\n\t{{ template \"input.gotpl\" $input }}\n{{- end }}\n\nfunc (ec *executionContext) FieldMiddleware(ctx context.Context, obj interface{}, next graphql.Resolver) (ret interface{}) {\n\tdefer func() {\n\t\tif r := recover(); r != nil {\n\t\t\tec.Error(ctx, ec.Recover(ctx, r))\n\t\t\tret = nil\n\t\t}\n\t}()\n\t{{- if .Directives }}\n\trctx := graphql.GetResolverContext(ctx)\n\tfor _, d := range rctx.Field.Definition.Directives {\n\t\tswitch d.Name {\n\t\t{{- range $directive := .Directives }}\n\t\tcase \"{{$directive.Name}}\":\n\t\t\tif ec.directives.{{$directive.Name|ucFirst}} != nil {\n\t\t\t\t{{- if $directive.Args }}\n\t\t\t\t\trawArgs := d.ArgumentMap(ec.Variables)\n\t\t\t\t\targs, err := {{ $directive.ArgsFunc }}(rawArgs)\n\t\t\t\t\tif err != nil {\n\t\t\t\t\t\tec.Error(ctx, err)\n\t\t\t\t\t\treturn nil\n\t\t\t\t\t}\n\t\t\t\t{{- end }}\n\t\t\t\tn := next\n\t\t\t\tnext = func(ctx context.Context) (interface{}, error) {\n\t\t\t\t\treturn ec.directives.{{$directive.Name|ucFirst}}({{$directive.CallArgs}})\n\t\t\t\t}\n\t\t\t}\n\t\t{{- end }}\n\t\t}\n\t}\n\t{{- end }}\n\tres, err := ec.ResolverMiddleware(ctx, next)\n\tif err != nil {\n\t\tec.Error(ctx, err)\n\t\treturn nil\n\t}\n\treturn res\n}\n\nfunc (ec *executionContext) introspectSchema() *introspection.Schema {\n\treturn introspection.WrapSchema(parsedSchema)\n}\n\nfunc (ec *executionContext) introspectType(name string) *introspection.Type {\n\treturn introspection.WrapTypeFromDef(parsedSchema, parsedSchema.Types[name])\n}\n\nvar parsedSchema = gqlparser.MustLoadSchema(\n\t&ast.Source{Name: {{.SchemaFilename|quote}}, Input: {{.SchemaRaw|rawQuote}}},\n)\n",
 	"input.gotpl":     "\t{{- if .IsMarshaled }}\n\tfunc Unmarshal{{ .GQLType }}(v interface{}) ({{.FullName}}, error) {\n\t\tvar it {{.FullName}}\n\t\tvar asMap = v.(map[string]interface{})\n\t\t{{ range $field := .Fields}}\n\t\t\t{{- if $field.Default}}\n\t\t\t\tif _, present := asMap[{{$field.GQLName|quote}}] ; !present {\n\t\t\t\t\tasMap[{{$field.GQLName|quote}}] = {{ $field.Default | dump }}\n\t\t\t\t}\n\t\t\t{{- end}}\n\t\t{{- end }}\n\n\t\tfor k, v := range asMap {\n\t\t\tswitch k {\n\t\t\t{{- range $field := .Fields }}\n\t\t\tcase {{$field.GQLName|quote}}:\n\t\t\t\tvar err error\n\t\t\t\t{{ $field.Unmarshal (print \"it.\" $field.GoFieldName) \"v\" }}\n\t\t\t\tif err != nil {\n\t\t\t\t\treturn it, err\n\t\t\t\t}\n\t\t\t{{- end }}\n\t\t\t}\n\t\t}\n\n\t\treturn it, nil\n\t}\n\t{{- end }}\n",
 	"interface.gotpl": "{{- $interface := . }}\n\nfunc (ec *executionContext) _{{$interface.GQLType}}(ctx context.Context, sel ast.SelectionSet, obj *{{$interface.FullName}}) graphql.Marshaler {\n\tswitch obj := (*obj).(type) {\n\tcase nil:\n\t\treturn graphql.Null\n\t{{- range $implementor := $interface.Implementors }}\n\t\t{{- if $implementor.ValueReceiver }}\n\t\t\tcase {{$implementor.FullName}}:\n\t\t\t\treturn ec._{{$implementor.GQLType}}(ctx, sel, &obj)\n\t\t{{- end}}\n\t\tcase *{{$implementor.FullName}}:\n\t\t\treturn ec._{{$implementor.GQLType}}(ctx, sel, obj)\n\t{{- end }}\n\tdefault:\n\t\tpanic(fmt.Errorf(\"unexpected type %T\", obj))\n\t}\n}\n",
-	"models.gotpl":    "// Code generated by github.com/99designs/gqlgen, DO NOT EDIT.\n\npackage {{ .PackageName }}\n\nimport (\n{{- range $import := .Imports }}\n\t{{- $import.Write }}\n{{ end }}\n)\n\n{{ range $model := .Models }}\n\t{{with .Description}} {{.|prefixLines \"// \"}} {{end}}\n\t{{- if .IsInterface }}\n\t\ttype {{.GoType}} interface {\n\t\t\tIs{{.GoType}}()\n\t\t}\n\t{{- else }}\n\t\ttype {{.GoType}} struct {\n\t\t\t{{- range $field := .Fields }}\n\t\t\t\t{{- with .Description}}\n\t\t\t\t\t{{.|prefixLines \"// \"}}\n\t\t\t\t{{- end}}\n\t\t\t\t{{- if $field.GoFieldName }}\n\t\t\t\t\t{{ $field.GoFieldName }} {{$field.Signature}} `json:\"{{$field.GQLName}}\"`\n\t\t\t\t{{- else }}\n\t\t\t\t\t{{ $field.GoFKName }} {{$field.GoFKType}}\n\t\t\t\t{{- end }}\n\t\t\t{{- end }}\n\t\t}\n\n\t\t{{- range $iface := .Implements }}\n\t\t\tfunc ({{$model.GoType}}) Is{{$iface.GoType}}() {}\n\t\t{{- end }}\n\n\t{{- end }}\n{{- end}}\n\n{{ range $enum := .Enums }}\n\t{{with .Description}}{{.|prefixLines \"// \"}} {{end}}\n\ttype {{.GoType}} string\n\tconst (\n\t{{- range $value := .Values}}\n\t\t{{- with .Description}}\n\t\t\t{{.|prefixLines \"// \"}}\n\t\t{{- end}}\n\t\t{{$enum.GoType}}{{ .Name|toCamel }} {{$enum.GoType}} = {{.Name|quote}}\n\t{{- end }}\n\t)\n\n\tfunc (e {{.GoType}}) IsValid() bool {\n\t\tswitch e {\n\t\tcase {{ range $index, $element := .Values}}{{if $index}},{{end}}{{ $enum.GoType }}{{ $element.Name|toCamel }}{{end}}:\n\t\t\treturn true\n\t\t}\n\t\treturn false\n\t}\n\n\tfunc (e {{.GoType}}) String() string {\n\t\treturn string(e)\n\t}\n\n\tfunc (e *{{.GoType}}) UnmarshalGQL(v interface{}) error {\n\t\tstr, ok := v.(string)\n\t\tif !ok {\n\t\t\treturn fmt.Errorf(\"enums must be strings\")\n\t\t}\n\n\t\t*e = {{.GoType}}(str)\n\t\tif !e.IsValid() {\n\t\t\treturn fmt.Errorf(\"%s is not a valid {{.GQLType}}\", str)\n\t\t}\n\t\treturn nil\n\t}\n\n\tfunc (e {{.GoType}}) MarshalGQL(w io.Writer) {\n\t\tfmt.Fprint(w, strconv.Quote(e.String()))\n\t}\n\n{{- end }}\n",
+	"models.gotpl":    "// Code generated by github.com/99designs/gqlgen, DO NOT EDIT.\n\npackage {{ .PackageName }}\n\nimport (\n{{- range $import := .Imports }}\n\t{{- $import.Write }}\n{{ end }}\n)\n\n{{ range $model := .Models }}\n\t{{with .Description}} {{.|prefixLines \"// \"}} {{end}}\n\t{{- if .IsInterface }}\n\t\ttype {{.GoType}} interface {}\n\t{{- else }}\n\t\ttype {{.GoType}} struct {\n\t\t\t{{- range $field := .Fields }}\n\t\t\t\t{{- with .Description}}\n\t\t\t\t\t{{.|prefixLines \"// \"}}\n\t\t\t\t{{- end}}\n\t\t\t\t{{- if $field.GoFieldName }}\n\t\t\t\t\t{{ $field.GoFieldName }} {{$field.Signature}} `json:\"{{$field.GQLName}}\"`\n\t\t\t\t{{- else }}\n\t\t\t\t\t{{ $field.GoFKName }} {{$field.GoFKType}}\n\t\t\t\t{{- end }}\n\t\t\t{{- end }}\n\t\t}\n\t{{- end }}\n{{- end}}\n\n{{ range $enum := .Enums }}\n\t{{with .Description}}{{.|prefixLines \"// \"}} {{end}}\n\ttype {{.GoType}} string\n\tconst (\n\t{{- range $value := .Values}}\n\t\t{{- with .Description}}\n\t\t\t{{.|prefixLines \"// \"}}\n\t\t{{- end}}\n\t\t{{$enum.GoType}}{{ .Name|toCamel }} {{$enum.GoType}} = {{.Name|quote}}\n\t{{- end }}\n\t)\n\n\tfunc (e {{.GoType}}) IsValid() bool {\n\t\tswitch e {\n\t\tcase {{ range $index, $element := .Values}}{{if $index}},{{end}}{{ $enum.GoType }}{{ $element.Name|toCamel }}{{end}}:\n\t\t\treturn true\n\t\t}\n\t\treturn false\n\t}\n\n\tfunc (e {{.GoType}}) String() string {\n\t\treturn string(e)\n\t}\n\n\tfunc (e *{{.GoType}}) UnmarshalGQL(v interface{}) error {\n\t\tstr, ok := v.(string)\n\t\tif !ok {\n\t\t\treturn fmt.Errorf(\"enums must be strings\")\n\t\t}\n\n\t\t*e = {{.GoType}}(str)\n\t\tif !e.IsValid() {\n\t\t\treturn fmt.Errorf(\"%s is not a valid {{.GQLType}}\", str)\n\t\t}\n\t\treturn nil\n\t}\n\n\tfunc (e {{.GoType}}) MarshalGQL(w io.Writer) {\n\t\tfmt.Fprint(w, strconv.Quote(e.String()))\n\t}\n\n{{- end }}\n",
 	"object.gotpl":    "{{ $object := . }}\n\nvar {{ $object.GQLType|lcFirst}}Implementors = {{$object.Implementors}}\n\n// nolint: gocyclo, errcheck, gas, goconst\n{{- if .Stream }}\nfunc (ec *executionContext) _{{$object.GQLType}}(ctx context.Context, sel ast.SelectionSet) func() graphql.Marshaler {\n\tfields := graphql.CollectFields(ctx, sel, {{$object.GQLType|lcFirst}}Implementors)\n\tctx = graphql.WithResolverContext(ctx, &graphql.ResolverContext{\n\t\tObject: {{$object.GQLType|quote}},\n\t})\n\tif len(fields) != 1 {\n\t\tec.Errorf(ctx, \"must subscribe to exactly one stream\")\n\t\treturn nil\n\t}\n\n\tswitch fields[0].Name {\n\t{{- range $field := $object.Fields }}\n\tcase \"{{$field.GQLName}}\":\n\t\treturn ec._{{$object.GQLType}}_{{$field.GQLName}}(ctx, fields[0])\n\t{{- end }}\n\tdefault:\n\t\tpanic(\"unknown field \" + strconv.Quote(fields[0].Name))\n\t}\n}\n{{- else }}\nfunc (ec *executionContext) _{{$object.GQLType}}(ctx context.Context, sel ast.SelectionSet{{if not $object.Root}}, obj *{{$object.FullName}} {{end}}) graphql.Marshaler {\n\tfields := graphql.CollectFields(ctx, sel, {{$object.GQLType|lcFirst}}Implementors)\n\t{{if $object.Root}}\n\t\tctx = graphql.WithResolverContext(ctx, &graphql.ResolverContext{\n\t\t\tObject: {{$object.GQLType|quote}},\n\t\t})\n\t{{end}}\n\n\t{{if $object.IsConcurrent}} var wg sync.WaitGroup {{end}}\n\tout := graphql.NewOrderedMap(len(fields))\n\tinvalid := false\n\tfor i, field := range fields {\n\t\tout.Keys[i] = field.Alias\n\n\t\tswitch field.Name {\n\t\tcase \"__typename\":\n\t\t\tout.Values[i] = graphql.MarshalString({{$object.GQLType|quote}})\n\t\t{{- range $field := $object.Fields }}\n\t\tcase \"{{$field.GQLName}}\":\n\t\t\t{{- if $field.IsConcurrent }}\n\t\t\t\twg.Add(1)\n\t\t\t\tgo func(i int, field graphql.CollectedField) {\n\t\t\t{{- end }}\n\t\t\t\tout.Values[i] = ec._{{$object.GQLType}}_{{$field.GQLName}}(ctx, field{{if not $object.Root}}, obj{{end}})\n\t\t\t\t{{- if $field.ASTType.NonNull }}\n\t\t\t\t\tif out.Values[i] == graphql.Null {\n\t\t\t\t\t\tinvalid = true\n\t\t\t\t\t}\n\t\t\t\t{{- end }}\n\t\t\t{{- if $field.IsConcurrent }}\n\t\t\t\t\twg.Done()\n\t\t\t\t}(i, field)\n\t\t\t{{- end }}\n\t\t{{- end }}\n\t\tdefault:\n\t\t\tpanic(\"unknown field \" + strconv.Quote(field.Name))\n\t\t}\n\t}\n\t{{if $object.IsConcurrent}} wg.Wait() {{end}}\n\tif invalid { return graphql.Null }\n\treturn out\n}\n{{- end }}\n",
 	"resolver.gotpl":  "//go:generate gorunpkg github.com/99designs/gqlgen\n\npackage {{ .PackageName }}\n\nimport (\n{{- range $import := .Imports }}\n\t{{- $import.Write }}\n{{ end }}\n)\n\ntype {{.ResolverType}} struct {}\n\n{{ range $object := .Objects -}}\n\t{{- if $object.HasResolvers -}}\n\t\tfunc (r *{{$.ResolverType}}) {{$object.GQLType}}() {{ $object.ResolverInterface.FullName }} {\n\t\t\treturn &{{lcFirst $object.GQLType}}Resolver{r}\n\t\t}\n\t{{ end -}}\n{{ end }}\n\n{{ range $object := .Objects -}}\n\t{{- if $object.HasResolvers -}}\n\t\ttype {{lcFirst $object.GQLType}}Resolver struct { *Resolver }\n\n\t\t{{ range $field := $object.Fields -}}\n\t\t\t{{- if $field.IsResolver -}}\n\t\t\tfunc (r *{{lcFirst $object.GQLType}}Resolver) {{ $field.ShortResolverDeclaration }} {\n\t\t\t\tpanic(\"not implemented\")\n\t\t\t}\n\t\t\t{{ end -}}\n\t\t{{ end -}}\n\t{{ end -}}\n{{ end }}\n",
 	"server.gotpl":    "package main\n\nimport (\n{{- range $import := .Imports }}\n\t{{- $import.Write }}\n{{ end }}\n)\n\nconst defaultPort = \"8080\"\n\nfunc main() {\n\tport := os.Getenv(\"PORT\")\n\tif port == \"\" {\n\t\tport = defaultPort\n\t}\n\n\thttp.Handle(\"/\", handler.Playground(\"GraphQL playground\", \"/query\"))\n\thttp.Handle(\"/query\", handler.GraphQL({{.ExecPackageName}}.NewExecutableSchema({{.ExecPackageName}}.Config{Resolvers: &{{.ResolverPackageName}}.Resolver{}})))\n\n\tlog.Printf(\"connect to http://localhost:%s/ for GraphQL playground\", port)\n\tlog.Fatal(http.ListenAndServe(\":\" + port, nil))\n}\n",
diff --git a/codegen/templates/models.gotpl b/codegen/templates/models.gotpl
index 4777397e7b6..7427d71d7a4 100644
--- a/codegen/templates/models.gotpl
+++ b/codegen/templates/models.gotpl
@@ -11,9 +11,7 @@ import (
 {{ range $model := .Models }}
 	{{with .Description}} {{.|prefixLines "// "}} {{end}}
 	{{- if .IsInterface }}
-		type {{.GoType}} interface {
-			Is{{.GoType}}()
-		}
+		type {{.GoType}} interface {}
 	{{- else }}
 		type {{.GoType}} struct {
 			{{- range $field := .Fields }}
@@ -27,11 +25,6 @@ import (
 				{{- end }}
 			{{- end }}
 		}
-
-		{{- range $iface := .Implements }}
-			func ({{$model.GoType}}) Is{{$iface.GoType}}() {}
-		{{- end }}
-
 	{{- end }}
 {{- end}}
 
diff --git a/codegen/testserver/interfaces.go b/codegen/testserver/interfaces.go
index 18488d8153f..a1500ebf4a7 100644
--- a/codegen/testserver/interfaces.go
+++ b/codegen/testserver/interfaces.go
@@ -4,12 +4,10 @@ import "math"
 
 type Shape interface {
 	Area() float64
-	isShape()
 }
 
 type ShapeUnion interface {
 	Area() float64
-	isShapeUnion()
 }
 
 type Circle struct {
@@ -20,9 +18,6 @@ func (c *Circle) Area() float64 {
 	return c.Radius * math.Pi * math.Pi
 }
 
-func (c *Circle) isShapeUnion() {}
-func (c *Circle) isShape()      {}
-
 type Rectangle struct {
 	Length, Width float64
 }
@@ -30,5 +25,3 @@ type Rectangle struct {
 func (r *Rectangle) Area() float64 {
 	return r.Length * r.Width
 }
-func (r *Rectangle) isShapeUnion() {}
-func (r *Rectangle) isShape()      {}
diff --git a/example/selection/models_gen.go b/example/selection/models_gen.go
index a94b368c070..ec05898826d 100644
--- a/example/selection/models_gen.go
+++ b/example/selection/models_gen.go
@@ -6,9 +6,7 @@ import (
 	time "time"
 )
 
-type Event interface {
-	IsEvent()
-}
+type Event interface{}
 
 type Like struct {
 	Reaction  string    `json:"reaction"`
@@ -17,13 +15,9 @@ type Like struct {
 	Collected []string  `json:"collected"`
 }
 
-func (Like) IsEvent() {}
-
 type Post struct {
 	Message   string    `json:"message"`
 	Sent      time.Time `json:"sent"`
 	Selection []string  `json:"selection"`
 	Collected []string  `json:"collected"`
 }
-
-func (Post) IsEvent() {}
diff --git a/example/starwars/model.go b/example/starwars/model.go
index 4ff05e0bfd9..557f59a8472 100644
--- a/example/starwars/model.go
+++ b/example/starwars/model.go
@@ -34,9 +34,6 @@ func (h *Human) Height(unit LengthUnit) float64 {
 	}
 }
 
-func (Human) IsCharacter()    {}
-func (Human) IsSearchResult() {}
-
 type Review struct {
 	Stars      int
 	Commentary *string
@@ -48,9 +45,6 @@ type Droid struct {
 	PrimaryFunction string
 }
 
-func (Droid) IsCharacter()    {}
-func (Droid) IsSearchResult() {}
-
 func (r *Resolver) resolveFriendConnection(ctx context.Context, ids []string, first *int, after *string) (FriendsConnection, error) {
 	from := 0
 	if after != nil {
diff --git a/example/starwars/models_gen.go b/example/starwars/models_gen.go
index 4d0d65df4ef..b34acb08797 100644
--- a/example/starwars/models_gen.go
+++ b/example/starwars/models_gen.go
@@ -8,9 +8,7 @@ import (
 	strconv "strconv"
 )
 
-type Character interface {
-	IsCharacter()
-}
+type Character interface{}
 
 type FriendsEdge struct {
 	Cursor string    `json:"cursor"`
@@ -23,9 +21,7 @@ type PageInfo struct {
 	HasNextPage bool   `json:"hasNextPage"`
 }
 
-type SearchResult interface {
-	IsSearchResult()
-}
+type SearchResult interface{}
 
 type Starship struct {
 	ID      string  `json:"id"`
@@ -34,8 +30,6 @@ type Starship struct {
 	History [][]int `json:"history"`
 }
 
-func (Starship) IsSearchResult() {}
-
 type Episode string
 
 const (