POC: ast visitor type guards

examples/federation/gateway/main.go

@@ -19,7 +19,6 @@ import (
 )
 
 // It's just a simple example of graphql federation gateway server, it's NOT a production ready code.
-//
 func logger() log.Logger {
 	logger, err := zap.NewDevelopmentConfig().Build()
 	if err != nil {
@@ -59,7 +58,7 @@ func startServer() {
 
 	datasourceWatcher := NewDatasourcePoller(httpClient, DatasourcePollerConfig{
 		Services: []ServiceConfig{
-			{Name: "accounts", URL: "http://localhost:4008/query", Fallback: fallback},
+			{Name: "accounts", URL: "http://localhost:4001/query", Fallback: fallback},
 			{Name: "products", URL: "http://localhost:4002/query", WS: "ws://localhost:4002/query"},
 			{Name: "reviews", URL: "http://localhost:4003/query"},
 		},

examples/federation/go.sum

@@ -57,7 +57,7 @@ github.com/golang/protobuf v1.5.0 h1:LUVKkCeviFUMKqHa4tXIIij/lbhnMbP7Fn5wKdKkRh4
 github.com/golang/protobuf v1.5.0/go.mod h1:FsONVRAS9T7sI+LIUmWTfcYkHO4aIWwzhcaSAoJOfIk=
 github.com/google/go-cmp v0.4.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/go-cmp v0.5.5/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
-github.com/google/go-cmp v0.5.6 h1:BKbKCqvP6I+rmFHt06ZmyQtvB8xAkWdhFyr0ZUNZcxQ=
+github.com/google/go-cmp v0.5.8 h1:e6P7q2lk1O+qJJb4BtCQXlK8vWEO8V1ZeuEdJNOqZyg=
 github.com/google/gofuzz v1.0.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
 github.com/google/renameio v0.1.0/go.mod h1:KWCgfxg9yswjAJkECMjeO8J8rahYeXnNhOm40UhjYkI=
 github.com/google/uuid v1.1.1 h1:Gkbcsh/GbpXz7lPftLA3P6TYMwjCLYm83jiFQZF/3gY=
@@ -188,8 +188,6 @@ golang.org/x/crypto v0.0.0-20190510104115-cbcb75029529/go.mod h1:yigFU9vqHzYiE8U
 golang.org/x/crypto v0.0.0-20191227163750-53104e6ec876/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
 golang.org/x/crypto v0.0.0-20210314154223-e6e6c4f2bb5b/go.mod h1:T9bdIzuCu7OtxOm1hfPfRQxPLYneinmdGuTeoZ9dtd4=
 golang.org/x/crypto v0.0.0-20210921155107-089bfa567519/go.mod h1:GvvjBRRGRdwPK5ydBHafDWAxML/pGHZbMvKqRZ5+Abc=
-golang.org/x/crypto v0.0.0-20220315160706-3147a52a75dd h1:XcWmESyNjXJMLahc3mqVQJcgSTDxFxhETVlfk9uGc38=
-golang.org/x/crypto v0.0.0-20220315160706-3147a52a75dd/go.mod h1:IxCIyHEi3zRg3s0A5j5BB6A9Jmi73HwBIUl50j+osU4=
 golang.org/x/crypto v0.1.0 h1:MDRAIl0xIo9Io2xV565hzXHw3zVseKrJKodhohM5CjU=
 golang.org/x/crypto v0.1.0/go.mod h1:RecgLatLF4+eUMCP1PoPZQb+cVrJcOPbHkTkbkB9sbw=
 golang.org/x/exp v0.0.0-20230203172020-98cc5a0785f9 h1:frX3nT9RkKybPnjyI+yvZh6ZucTZatCCEm9D47sZ2zo=
@@ -198,16 +196,15 @@ golang.org/x/lint v0.0.0-20190930215403-16217165b5de/go.mod h1:6SW0HCj/g11FgYtHl
 golang.org/x/lint v0.0.0-20191125180803-fdd1cda4f05f h1:J5lckAjkw6qYlOZNj90mLYNTEKDvWeuc1yieZ8qUzUE=
 golang.org/x/mod v0.0.0-20190513183733-4bf6d317e70e/go.mod h1:mXi4GBBbnImb6dmsKGUJ2LatrhH/nqhxcFungHvyanc=
 golang.org/x/mod v0.6.0-dev.0.20220106191415-9b9b3d81d5e3/go.mod h1:3p9vT2HGsQu2K1YbXdKPJLVgG5VJdoTa1poYQBtP1AY=
-golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4 h1:6zppjxzCulZykYSLyVDYbneBfbaBIQPYMevg0bEwv2s=
 golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4/go.mod h1:jJ57K6gSWd91VN4djpZkiMVwK6gcyfeH4XE8wZrZaV4=
+golang.org/x/mod v0.6.0 h1:b9gGHsz9/HhJ3HF5DHQytPpuwocVTChQJK3AvoLRD5I=
 golang.org/x/mod v0.6.0/go.mod h1:4mET923SAdbXp2ki8ey+zGs1SLqsuM2Y0uvdZR/fUNI=
 golang.org/x/net v0.0.0-20190311183353-d8887717615a/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 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 v0.0.0-20191116160921-f9c825593386/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20210226172049-e18ecbb05110/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
 golang.org/x/net v0.0.0-20211015210444-4f30a5c0130f/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
-golang.org/x/net v0.0.0-20220722155237-a158d28d115b h1:PxfKdU9lEEDYjdIzOtC4qFWgkU2rGHdKlKowJSMN9h0=
 golang.org/x/net v0.0.0-20220722155237-a158d28d115b/go.mod h1:XRhObCWvk6IyKnWLug+ECip1KBveYUHfp+8e9klMJ9c=
 golang.org/x/net v0.1.0 h1:hZ/3BUoy5aId7sCpA/Tc5lt8DkFgdVS2onTpJsZ/fl0=
 golang.org/x/net v0.1.0/go.mod h1:Cx3nUiGt4eDBEyega/BKRp+/AlGL8hYe7U9odMt2Cco=
@@ -226,7 +223,6 @@ golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBc
 golang.org/x/sys v0.0.0-20211019181941-9d821ace8654/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.0.0-20220811171246-fbc7d0a398ab h1:2QkjZIsXupsJbJIdSjjUOgWK3aEtzyuh2mPt3l/CkeU=
 golang.org/x/sys v0.0.0-20220811171246-fbc7d0a398ab/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.1.0 h1:kunALQeHf1/185U1i0GOB/fy1IPRDDpuoOOqRReG57U=
 golang.org/x/sys v0.1.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
@@ -237,8 +233,8 @@ golang.org/x/text v0.3.2/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=
 golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
 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/text v0.3.8 h1:nAL+RVCQ9uMn3vJZbV+MRnydTJFPf8qqY42YiA6MrqY=
 golang.org/x/text v0.3.8/go.mod h1:E6s5w1FMmriuDzIBO73fBruAKo1PCIq6d2Q6DHfQ8WQ=
+golang.org/x/text v0.4.0 h1:BrVqGRd7+k1DiOgtnFvAkoQEWQvBc25ouMJM6429SFg=
 golang.org/x/text v0.4.0/go.mod h1:mrYo+phRRbMaCq/xk9113O4dZlRixOauAjOtrjsXDZ8=
 golang.org/x/time v0.0.0-20191024005414-555d28b269f0/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
 golang.org/x/time v0.0.0-20211116232009-f0f3c7e86c11 h1:GZokNIeuVkl3aZHJchRrr13WCsols02MLUcz1U9is6M=
@@ -251,8 +247,8 @@ golang.org/x/tools v0.0.0-20191029190741-b9c20aec41a5/go.mod h1:b+2E5dAYhXwXZwtn
 golang.org/x/tools v0.0.0-20191108193012-7d206e10da11/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
 golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
 golang.org/x/tools v0.1.10/go.mod h1:Uh6Zz+xoGYZom868N8YTex3t7RhtHDBrE8Gzo9bV56E=
-golang.org/x/tools v0.1.12 h1:VveCTK38A2rkS8ZqFY25HIDFscX5X9OoEhJd3quQmXU=
 golang.org/x/tools v0.1.12/go.mod h1:hNGJHUnrk76NpqgfD5Aqm5Crs+Hm0VOH/i9J2+nxYbc=
+golang.org/x/tools v0.2.0 h1:G6AHpWxTMGY1KyEYoAQ5WTtIekUUvDNjan3ugu60JvE=
 golang.org/x/tools v0.2.0/go.mod h1:y4OqIKeOV/fWJetJ8bXPU1sEVniLMIyDAZWeHdV+NTA=
 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=

pkg/ast/ast_fragment_definition.go

@@ -7,6 +7,8 @@ import (
 	"github.com/wundergraph/graphql-go-tools/pkg/lexer/position"
 )
 
+type FragmentDefinitionRef int
+
 // TypeCondition
 // example:
 // on User
@@ -17,11 +19,12 @@ type TypeCondition struct {
 
 // FragmentDefinition
 // example:
-// fragment friendFields on User {
-//  id
-//  name
-//  profilePic(size: 50)
-// }
+//
+//	fragment friendFields on User {
+//	 id
+//	 name
+//	 profilePic(size: 50)
+//	}
 type FragmentDefinition struct {
 	FragmentLiteral position.Position  // fragment
 	Name            ByteSliceReference // Name but not on, e.g. friendFields
@@ -32,30 +35,30 @@ type FragmentDefinition struct {
 	HasSelections   bool
 }
 
-func (d *Document) FragmentDefinitionRef(byName ByteSlice) (ref int, exists bool) {
+func (d *Document) FragmentDefinitionRef(byName ByteSlice) (ref FragmentDefinitionRef, exists bool) {
 	for i := range d.FragmentDefinitions {
 		if bytes.Equal(byName, d.Input.ByteSlice(d.FragmentDefinitions[i].Name)) {
-			return i, true
+			return FragmentDefinitionRef(i), true
 		}
 	}
 	return -1, false
 }
 
-func (d *Document) FragmentDefinitionTypeName(ref int) ByteSlice {
+func (d *Document) FragmentDefinitionTypeName(ref FragmentDefinitionRef) ByteSlice {
 	return d.ResolveTypeNameBytes(d.FragmentDefinitions[ref].TypeCondition.Type)
 }
 
-func (d *Document) FragmentDefinitionNameBytes(ref int) ByteSlice {
+func (d *Document) FragmentDefinitionNameBytes(ref FragmentDefinitionRef) ByteSlice {
 	return d.Input.ByteSlice(d.FragmentDefinitions[ref].Name)
 }
 
-func (d *Document) FragmentDefinitionNameString(ref int) string {
+func (d *Document) FragmentDefinitionNameString(ref FragmentDefinitionRef) string {
 	return unsafebytes.BytesToString(d.Input.ByteSlice(d.FragmentDefinitions[ref].Name))
 }
 
-func (d *Document) FragmentDefinitionIsLastRootNode(ref int) bool {
+func (d *Document) FragmentDefinitionIsLastRootNode(ref FragmentDefinitionRef) bool {
 	for i := range d.RootNodes {
-		if d.RootNodes[i].Kind == NodeKindFragmentDefinition && d.RootNodes[i].Ref == ref {
+		if d.RootNodes[i].Kind == NodeKindFragmentDefinition && d.RootNodes[i].Ref == int(ref) {
 			return len(d.RootNodes)-1 == i
 		}
 	}

pkg/ast/ast_fragment_spread.go

@@ -5,6 +5,8 @@ import (
 	"github.com/wundergraph/graphql-go-tools/pkg/lexer/position"
 )
 
+type FragmentSpreadRef int
+
 // FragmentSpread
 // example:
 // ...MyFragment
@@ -15,7 +17,7 @@ type FragmentSpread struct {
 	Directives    DirectiveList // optional, e.g. @foo
 }
 
-func (d *Document) CopyFragmentSpread(ref int) int {
+func (d *Document) CopyFragmentSpread(ref FragmentSpreadRef) FragmentSpreadRef {
 	var directives DirectiveList
 	if d.FragmentSpreads[ref].HasDirectives {
 		directives = d.CopyDirectiveList(d.FragmentSpreads[ref].Directives)
@@ -27,16 +29,16 @@ func (d *Document) CopyFragmentSpread(ref int) int {
 	})
 }
 
-func (d *Document) AddFragmentSpread(spread FragmentSpread) int {
+func (d *Document) AddFragmentSpread(spread FragmentSpread) FragmentSpreadRef {
 	d.FragmentSpreads = append(d.FragmentSpreads, spread)
-	return len(d.FragmentSpreads) - 1
+	return FragmentSpreadRef(len(d.FragmentSpreads) - 1)
 }
 
-func (d *Document) FragmentSpreadNameBytes(ref int) ByteSlice {
+func (d *Document) FragmentSpreadNameBytes(ref FragmentSpreadRef) ByteSlice {
 	return d.Input.ByteSlice(d.FragmentSpreads[ref].FragmentName)
 }
 
-func (d *Document) FragmentSpreadNameString(ref int) string {
+func (d *Document) FragmentSpreadNameString(ref FragmentSpreadRef) string {
 	return unsafebytes.BytesToString(d.FragmentSpreadNameBytes(ref))
 }
 
@@ -45,20 +47,20 @@ func (d *Document) FragmentSpreadNameString(ref int) string {
 // possible problems: changing directives or sub selections will affect both fields with the same id
 // simple solution: run normalization deduplicate fields
 // as part of the normalization flow this problem will be handled automatically
-// just be careful in case you use this function outside of the normalization package
-func (d *Document) ReplaceFragmentSpread(selectionSet int, spreadRef int, replaceWithSelectionSet int) {
+// just be careful in case you use this function outside the normalization package
+func (d *Document) ReplaceFragmentSpread(selectionSet int, spreadRef FragmentSpreadRef, replaceWithSelectionSet int) {
 	for i, j := range d.SelectionSets[selectionSet].SelectionRefs {
-		if d.Selections[j].Kind == SelectionKindFragmentSpread && d.Selections[j].Ref == spreadRef {
+		if d.Selections[j].Kind == SelectionKindFragmentSpread && d.Selections[j].Ref == int(spreadRef) {
 			d.SelectionSets[selectionSet].SelectionRefs = append(d.SelectionSets[selectionSet].SelectionRefs[:i], append(d.SelectionSets[replaceWithSelectionSet].SelectionRefs, d.SelectionSets[selectionSet].SelectionRefs[i+1:]...)...)
-			d.Index.ReplacedFragmentSpreads = append(d.Index.ReplacedFragmentSpreads, spreadRef)
+			d.Index.ReplacedFragmentSpreads = append(d.Index.ReplacedFragmentSpreads, int(spreadRef))
 			return
 		}
 	}
 }
 
-// ReplaceFragmentSpreadWithInlineFragment replaces a given fragment spread with a inline fragment
+// ReplaceFragmentSpreadWithInlineFragment replaces a given fragment spread with an inline fragment
 // attention! the same rules apply as for 'ReplaceFragmentSpread', look above!
-func (d *Document) ReplaceFragmentSpreadWithInlineFragment(selectionSet int, spreadRef int, replaceWithSelectionSet int, typeCondition TypeCondition) {
+func (d *Document) ReplaceFragmentSpreadWithInlineFragment(selectionSet int, spreadRef FragmentSpreadRef, replaceWithSelectionSet int, typeCondition TypeCondition) {
 	d.InlineFragments = append(d.InlineFragments, InlineFragment{
 		TypeCondition: typeCondition,
 		SelectionSet:  replaceWithSelectionSet,
@@ -71,9 +73,9 @@ func (d *Document) ReplaceFragmentSpreadWithInlineFragment(selectionSet int, spr
 	})
 	selectionRef := len(d.Selections) - 1
 	for i, j := range d.SelectionSets[selectionSet].SelectionRefs {
-		if d.Selections[j].Kind == SelectionKindFragmentSpread && d.Selections[j].Ref == spreadRef {
+		if d.Selections[j].Kind == SelectionKindFragmentSpread && d.Selections[j].Ref == int(spreadRef) {
 			d.SelectionSets[selectionSet].SelectionRefs = append(d.SelectionSets[selectionSet].SelectionRefs[:i], append([]int{selectionRef}, d.SelectionSets[selectionSet].SelectionRefs[i+1:]...)...)
-			d.Index.ReplacedFragmentSpreads = append(d.Index.ReplacedFragmentSpreads, spreadRef)
+			d.Index.ReplacedFragmentSpreads = append(d.Index.ReplacedFragmentSpreads, int(spreadRef))
 			return
 		}
 	}

pkg/astvalidation/operation_rule_fragments.go

@@ -29,14 +29,23 @@ type fragmentsVisitor struct {
 	fragmentDefinitionsVisited []ast.ByteSlice
 }
 
-func (f *fragmentsVisitor) EnterFragmentSpread(ref int) {
-	if f.Ancestors[0].Kind == ast.NodeKindOperationDefinition {
-		spreadName := f.operation.FragmentSpreadNameBytes(ref)
-		f.StopWithExternalErr(operationreport.ErrFragmentSpreadFormsCycle(spreadName))
+func (f *fragmentsVisitor) EnterFragmentSpread(ref ast.FragmentSpreadRef) {
+	fragmentName := f.operation.FragmentSpreadNameBytes(ref)
+	defer func() {
+		if r := recover(); r != nil {
+			f.StopWithExternalErr(operationreport.ErrFragmentUndefined(fragmentName))
+		}
+	}()
+	fragmentTypeName := f.operation.FragmentDefinitionTypeName(ref)
+	enclosingTypeName := f.EnclosingTypeDefinition.NameBytes(f.definition)
+	if !bytes.Equal(fragmentTypeName, enclosingTypeName) {
+		f.StopWithExternalErr(operationreport.ErrInvalidFragmentSpread(fragmentName, fragmentTypeName, enclosingTypeName))
+	} else if f.Ancestors[0].Kind == ast.NodeKindOperationDefinition {
+		f.StopWithExternalErr(operationreport.ErrFragmentSpreadFormsCycle(fragmentName))
 	}
 }
 
-func (f *fragmentsVisitor) LeaveDocument(operation, definition *ast.Document) {
+func (f *fragmentsVisitor) LeaveDocument(_, _ *ast.Document) {
 	for i := range f.fragmentDefinitionsVisited {
 		if !f.operation.FragmentDefinitionIsUsed(f.fragmentDefinitionsVisited[i]) {
 			fragmentName := f.fragmentDefinitionsVisited[i]
@@ -89,7 +98,7 @@ func (f *fragmentsVisitor) EnterDocument(operation, definition *ast.Document) {
 	f.fragmentDefinitionsVisited = f.fragmentDefinitionsVisited[:0]
 }
 
-func (f *fragmentsVisitor) EnterFragmentDefinition(ref int) {
+func (f *fragmentsVisitor) EnterFragmentDefinition(ref ast.FragmentDefinitionRef) {
 
 	fragmentDefinitionName := f.operation.FragmentDefinitionNameBytes(ref)
 	typeName := f.operation.FragmentDefinitionTypeName(ref)

pkg/astvalidation/operation_validation_test.go

@@ -2547,7 +2547,7 @@ func TestExecutionValidation(t *testing.T) {
 										...undefinedFragment
 									}
 								}`,
-						Fragments(), Invalid, withExpectNormalizationError())
+						Fragments(), Invalid, withExpectNormalizationError(), withValidationErrors("undefinedFragment undefined"))
 				})
 			})
 			t.Run("5.5.2.2 Fragment spreads must not form cycles", func(t *testing.T) {
@@ -2566,7 +2566,7 @@ func TestExecutionValidation(t *testing.T) {
 						barkVolume
 						...nameFragment
 					}`,
-						Fragments(), Invalid)
+						Fragments(), Invalid, withValidationErrors("external: fragment spread: barkVolumeFragment forms fragment cycle"))
 				})
 				t.Run("136", func(t *testing.T) {
 					run(t, `
@@ -2669,6 +2669,18 @@ func TestExecutionValidation(t *testing.T) {
 									}`,
 							Fragments(), Valid)
 					})
+					t.Run("Spreading a fragment on an invalid type returns ErrInvalidFragmentSpread", func(t *testing.T) {
+						run(t, `
+									{
+										dog {
+											...invalidCatFragment
+										}
+									}
+									fragment invalidCatFragment on Cat {
+										meowVolume
+									}`,
+							Fragments(), Invalid, withValidationErrors("external: fragment spread: fragment invalidCatFragment must be spread on type Cat and not type Dog"))
+					})
 				})
 				t.Run("5.5.2.3.2 Abstract Spreads in Object Scope", func(t *testing.T) {
 					t.Run("139", func(t *testing.T) {

pkg/astvisitor/visitor.go

@@ -131,13 +131,13 @@ type (
 	EnterFragmentSpreadVisitor interface {
 		// EnterFragmentSpread gets called when the walker enters a fragment spread
 		// ref is the reference to the selection set on the AST
-		EnterFragmentSpread(ref int)
+		EnterFragmentSpread(ref ast.FragmentSpreadRef)
 	}
 	// LeaveFragmentSpreadVisitor is the callback when the walker leaves a fragment spread
 	LeaveFragmentSpreadVisitor interface {
 		// LeaveFragmentSpread gets called when the walker leaves a fragment spread
 		// ref is the reference to the selection set on the AST
-		LeaveFragmentSpread(ref int)
+		LeaveFragmentSpread(ref ast.FragmentSpreadRef)
 	}
 	// FragmentSpreadVisitor is the callback when the walker enters or leaves a fragment spread
 	FragmentSpreadVisitor interface {
@@ -165,13 +165,13 @@ type (
 	EnterFragmentDefinitionVisitor interface {
 		// EnterFragmentDefinition gets called when the walker enters a fragment definition
 		// ref is the reference to the selection set on the AST
-		EnterFragmentDefinition(ref int)
+		EnterFragmentDefinition(ref ast.FragmentDefinitionRef)
 	}
 	// LeaveFragmentDefinitionVisitor is the callback when the walker leaves a fragment definition
 	LeaveFragmentDefinitionVisitor interface {
 		// LeaveFragmentDefinition gets called when the walker leaves a fragment definition
 		// ref is the reference to the selection set on the AST
-		LeaveFragmentDefinition(ref int)
+		LeaveFragmentDefinition(ref ast.FragmentDefinitionRef)
 	}
 	// FragmentDefinitionVisitor is the callback when the walker enters or leaves a fragment definition
 	FragmentDefinitionVisitor interface {
@@ -1355,7 +1355,7 @@ func (w *Walker) appendAncestor(ref int, kind ast.NodeKind) {
 		}
 		typeName = w.document.InlineFragmentTypeConditionName(ref)
 	case ast.NodeKindFragmentDefinition:
-		typeName = w.document.FragmentDefinitionTypeName(ref)
+		typeName = w.document.FragmentDefinitionTypeName(ast.FragmentDefinitionRef(ref))
 		w.Path = append(w.Path, ast.PathItem{
 			Kind:       ast.FieldName,
 			ArrayIndex: 0,
@@ -1951,7 +1951,7 @@ func (w *Walker) walkFragmentSpread(ref int) {
 
 	for i := 0; i < len(w.visitors.enterFragmentSpread); {
 		if w.filter == nil || w.filter.AllowVisitor(EnterFragmentSpread, ref, w.visitors.enterFragmentSpread[i]) {
-			w.visitors.enterFragmentSpread[i].EnterFragmentSpread(ref)
+			w.visitors.enterFragmentSpread[i].EnterFragmentSpread(ast.FragmentSpreadRef(ref))
 		}
 		if w.revisit {
 			w.revisit = false
@@ -1970,7 +1970,7 @@ func (w *Walker) walkFragmentSpread(ref int) {
 
 	for i := 0; i < len(w.visitors.leaveFragmentSpread); {
 		if w.filter == nil || w.filter.AllowVisitor(LeaveFragmentSpread, ref, w.visitors.leaveFragmentSpread[i]) {
-			w.visitors.leaveFragmentSpread[i].LeaveFragmentSpread(ref)
+			w.visitors.leaveFragmentSpread[i].LeaveFragmentSpread(ast.FragmentSpreadRef(ref))
 		}
 		if w.revisit {
 			w.revisit = false
@@ -2071,7 +2071,7 @@ func (w *Walker) walkFragmentDefinition(ref int) {
 
 	for i := 0; i < len(w.visitors.enterFragmentDefinition); {
 		if w.filter == nil || w.filter.AllowVisitor(EnterFragmentDefinition, ref, w.visitors.enterFragmentDefinition[i]) {
-			w.visitors.enterFragmentDefinition[i].EnterFragmentDefinition(ref)
+			w.visitors.enterFragmentDefinition[i].EnterFragmentDefinition(ast.FragmentDefinitionRef(ref))
 		}
 		if w.revisit {
 			w.revisit = false
@@ -2112,7 +2112,7 @@ func (w *Walker) walkFragmentDefinition(ref int) {
 
 	for i := 0; i < len(w.visitors.leaveFragmentDefinition); {
 		if w.filter == nil || w.filter.AllowVisitor(LeaveFragmentDefinition, ref, w.visitors.leaveFragmentDefinition[i]) {
-			w.visitors.leaveFragmentDefinition[i].LeaveFragmentDefinition(ref)
+			w.visitors.leaveFragmentDefinition[i].LeaveFragmentDefinition(ast.FragmentDefinitionRef(ref))
 		}
 		if w.revisit {
 			w.revisit = false