From 75aa99ad2bfc9506c76bb86ff810461b699ec31d Mon Sep 17 00:00:00 2001
From: Adam <adam@vektah.net>
Date: Wed, 8 May 2019 21:54:40 +1000
Subject: [PATCH] Drop automatic conversion of IsZero to null

---
 codegen/config/binder.go                   |  19 ----
 codegen/testserver/generated.go            | 105 +++++++++++++++++----
 codegen/type.gotpl                         |  17 ++--
 example/chat/generated.go                  |  46 +++++++--
 example/config/generated.go                |  48 ++++++++--
 example/dataloader/generated.go            |  54 +++++++++--
 example/fileupload/generated.go            |  48 ++++++++--
 example/scalars/generated.go               |  43 +++++++--
 example/selection/generated.go             |  38 ++++++--
 example/starwars/generated/exec.go         |  59 ++++++++++--
 example/todo/generated.go                  |  48 ++++++++--
 example/type-system-extension/generated.go |  40 +++++++-
 graphql/time.go                            |   4 +
 integration/generated.go                   |  40 +++++++-
 14 files changed, 493 insertions(+), 116 deletions(-)

diff --git a/codegen/config/binder.go b/codegen/config/binder.go
index f39563874b4..41c3efef269 100644
--- a/codegen/config/binder.go
+++ b/codegen/config/binder.go
@@ -238,25 +238,6 @@ func (t *TypeReference) IsScalar() bool {
 	return t.Definition.Kind == ast.Scalar
 }
 
-func (t *TypeReference) HasIsZero() bool {
-	it := t.GO
-	if ptr, isPtr := it.(*types.Pointer); isPtr {
-		it = ptr.Elem()
-	}
-	namedType, ok := it.(*types.Named)
-	if !ok {
-		return false
-	}
-
-	for i := 0; i < namedType.NumMethods(); i++ {
-		switch namedType.Method(i).Name() {
-		case "IsZero":
-			return true
-		}
-	}
-	return false
-}
-
 func (t *TypeReference) UniquenessKey() string {
 	var nullability = "O"
 	if t.GQL.NonNull {
diff --git a/codegen/testserver/generated.go b/codegen/testserver/generated.go
index d10e371039f..75af34bc950 100644
--- a/codegen/testserver/generated.go
+++ b/codegen/testserver/generated.go
@@ -7258,7 +7258,13 @@ func (ec *executionContext) unmarshalNBoolean2bool(ctx context.Context, v interf
 }
 
 func (ec *executionContext) marshalNBoolean2bool(ctx context.Context, sel ast.SelectionSet, v bool) graphql.Marshaler {
-	return graphql.MarshalBoolean(v)
+	res := graphql.MarshalBoolean(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalNBytes2ᚕbyte(ctx context.Context, v interface{}) ([]byte, error) {
@@ -7266,7 +7272,13 @@ func (ec *executionContext) unmarshalNBytes2ᚕbyte(ctx context.Context, v inter
 }
 
 func (ec *executionContext) marshalNBytes2ᚕbyte(ctx context.Context, sel ast.SelectionSet, v []byte) graphql.Marshaler {
-	return MarshalBytes(v)
+	res := MarshalBytes(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalNDefaultScalarImplementation2string(ctx context.Context, v interface{}) (string, error) {
@@ -7274,7 +7286,13 @@ func (ec *executionContext) unmarshalNDefaultScalarImplementation2string(ctx con
 }
 
 func (ec *executionContext) marshalNDefaultScalarImplementation2string(ctx context.Context, sel ast.SelectionSet, v string) graphql.Marshaler {
-	return graphql.MarshalString(v)
+	res := graphql.MarshalString(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalNFallbackToStringEncoding2githubᚗcomᚋ99designsᚋgqlgenᚋcodegenᚋtestserverᚐFallbackToStringEncoding(ctx context.Context, v interface{}) (FallbackToStringEncoding, error) {
@@ -7283,7 +7301,13 @@ func (ec *executionContext) unmarshalNFallbackToStringEncoding2githubᚗcomᚋ99
 }
 
 func (ec *executionContext) marshalNFallbackToStringEncoding2githubᚗcomᚋ99designsᚋgqlgenᚋcodegenᚋtestserverᚐFallbackToStringEncoding(ctx context.Context, sel ast.SelectionSet, v FallbackToStringEncoding) graphql.Marshaler {
-	return graphql.MarshalString(string(v))
+	res := graphql.MarshalString(string(v))
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalNID2int(ctx context.Context, v interface{}) (int, error) {
@@ -7291,7 +7315,13 @@ func (ec *executionContext) unmarshalNID2int(ctx context.Context, v interface{})
 }
 
 func (ec *executionContext) marshalNID2int(ctx context.Context, sel ast.SelectionSet, v int) graphql.Marshaler {
-	return graphql.MarshalIntID(v)
+	res := graphql.MarshalIntID(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalNID2string(ctx context.Context, v interface{}) (string, error) {
@@ -7299,7 +7329,13 @@ func (ec *executionContext) unmarshalNID2string(ctx context.Context, v interface
 }
 
 func (ec *executionContext) marshalNID2string(ctx context.Context, sel ast.SelectionSet, v string) graphql.Marshaler {
-	return graphql.MarshalID(v)
+	res := graphql.MarshalID(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalNInnerDirectives2githubᚗcomᚋ99designsᚋgqlgenᚋcodegenᚋtestserverᚐInnerDirectives(ctx context.Context, v interface{}) (InnerDirectives, error) {
@@ -7323,7 +7359,13 @@ func (ec *executionContext) unmarshalNInt2int(ctx context.Context, v interface{}
 }
 
 func (ec *executionContext) marshalNInt2int(ctx context.Context, sel ast.SelectionSet, v int) graphql.Marshaler {
-	return graphql.MarshalInt(v)
+	res := graphql.MarshalInt(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalNInt2int32(ctx context.Context, v interface{}) (int32, error) {
@@ -7331,7 +7373,13 @@ func (ec *executionContext) unmarshalNInt2int32(ctx context.Context, v interface
 }
 
 func (ec *executionContext) marshalNInt2int32(ctx context.Context, sel ast.SelectionSet, v int32) graphql.Marshaler {
-	return graphql.MarshalInt32(v)
+	res := graphql.MarshalInt32(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalNInt2int64(ctx context.Context, v interface{}) (int64, error) {
@@ -7339,7 +7387,13 @@ func (ec *executionContext) unmarshalNInt2int64(ctx context.Context, v interface
 }
 
 func (ec *executionContext) marshalNInt2int64(ctx context.Context, sel ast.SelectionSet, v int64) graphql.Marshaler {
-	return graphql.MarshalInt64(v)
+	res := graphql.MarshalInt64(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalNMarshalPanic2githubᚗcomᚋ99designsᚋgqlgenᚋcodegenᚋtestserverᚐMarshalPanic(ctx context.Context, v interface{}) (MarshalPanic, error) {
@@ -7393,7 +7447,13 @@ func (ec *executionContext) unmarshalNString2string(ctx context.Context, v inter
 }
 
 func (ec *executionContext) marshalNString2string(ctx context.Context, sel ast.SelectionSet, v string) graphql.Marshaler {
-	return graphql.MarshalString(v)
+	res := graphql.MarshalString(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalNString2ᚕstring(ctx context.Context, v interface{}) ([]string, error) {
@@ -7477,13 +7537,13 @@ func (ec *executionContext) unmarshalNTime2timeᚐTime(ctx context.Context, v in
 }
 
 func (ec *executionContext) marshalNTime2timeᚐTime(ctx context.Context, sel ast.SelectionSet, v time.Time) graphql.Marshaler {
-	if v.IsZero() {
+	res := graphql.MarshalTime(v)
+	if res == graphql.Null {
 		if !ec.HasError(graphql.GetResolverContext(ctx)) {
 			ec.Errorf(ctx, "must not be null")
 		}
-		return graphql.Null
 	}
-	return graphql.MarshalTime(v)
+	return res
 }
 
 func (ec *executionContext) marshalNUser2githubᚗcomᚋ99designsᚋgqlgenᚋcodegenᚋtestserverᚐUser(ctx context.Context, sel ast.SelectionSet, v User) graphql.Marshaler {
@@ -7583,7 +7643,13 @@ func (ec *executionContext) unmarshalN__DirectiveLocation2string(ctx context.Con
 }
 
 func (ec *executionContext) marshalN__DirectiveLocation2string(ctx context.Context, sel ast.SelectionSet, v string) graphql.Marshaler {
-	return graphql.MarshalString(v)
+	res := graphql.MarshalString(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalN__DirectiveLocation2ᚕstring(ctx context.Context, v interface{}) ([]string, error) {
@@ -7748,7 +7814,13 @@ func (ec *executionContext) unmarshalN__TypeKind2string(ctx context.Context, v i
 }
 
 func (ec *executionContext) marshalN__TypeKind2string(ctx context.Context, sel ast.SelectionSet, v string) graphql.Marshaler {
-	return graphql.MarshalString(v)
+	res := graphql.MarshalString(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) marshalOAutobind2githubᚗcomᚋ99designsᚋgqlgenᚋcodegenᚋtestserverᚐAutobind(ctx context.Context, sel ast.SelectionSet, v Autobind) graphql.Marshaler {
@@ -8310,9 +8382,6 @@ func (ec *executionContext) unmarshalOTime2timeᚐTime(ctx context.Context, v in
 }
 
 func (ec *executionContext) marshalOTime2timeᚐTime(ctx context.Context, sel ast.SelectionSet, v time.Time) graphql.Marshaler {
-	if v.IsZero() {
-		return graphql.Null
-	}
 	return graphql.MarshalTime(v)
 }
 
diff --git a/codegen/type.gotpl b/codegen/type.gotpl
index f727baaca3c..cb2782c39ed 100644
--- a/codegen/type.gotpl
+++ b/codegen/type.gotpl
@@ -56,15 +56,6 @@
 					{{- end }}
 					return graphql.Null
 				}
-			{{- else if $type.HasIsZero }}
-				if v.IsZero() {
-					{{- if $type.GQL.NonNull }}
-						if !ec.HasError(graphql.GetResolverContext(ctx)) {
-							ec.Errorf(ctx, "must not be null")
-						}
-					{{- end }}
-					return graphql.Null
-				}
 			{{- end }}
 
 			{{- if $type.IsSlice }}
@@ -119,6 +110,14 @@
 				{{- else if $type.Marshaler }}
 					{{- if $type.IsPtr }}
 						return ec.{{ $type.Elem.MarshalFunc }}(ctx, sel, *v)
+					{{- else if $type.GQL.NonNull }}
+							res := {{ $type.Marshaler | call }}({{- if $type.CastType }}{{ $type.CastType | ref }}(v){{else}}v{{- end }})
+							if res == graphql.Null {
+								if !ec.HasError(graphql.GetResolverContext(ctx)) {
+									ec.Errorf(ctx, "must not be null")
+								}
+							}
+							return res
 					{{- else }}
 						return {{ $type.Marshaler | call }}({{- if $type.CastType }}{{ $type.CastType | ref }}(v){{else}}v{{- end }})
 					{{- end }}
diff --git a/example/chat/generated.go b/example/chat/generated.go
index 1ab366a3bcf..0e547eb4dde 100644
--- a/example/chat/generated.go
+++ b/example/chat/generated.go
@@ -1985,7 +1985,13 @@ func (ec *executionContext) unmarshalNBoolean2bool(ctx context.Context, v interf
 }
 
 func (ec *executionContext) marshalNBoolean2bool(ctx context.Context, sel ast.SelectionSet, v bool) graphql.Marshaler {
-	return graphql.MarshalBoolean(v)
+	res := graphql.MarshalBoolean(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalNID2string(ctx context.Context, v interface{}) (string, error) {
@@ -1993,7 +1999,13 @@ func (ec *executionContext) unmarshalNID2string(ctx context.Context, v interface
 }
 
 func (ec *executionContext) marshalNID2string(ctx context.Context, sel ast.SelectionSet, v string) graphql.Marshaler {
-	return graphql.MarshalID(v)
+	res := graphql.MarshalID(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) marshalNMessage2githubᚗcomᚋ99designsᚋgqlgenᚋexampleᚋchatᚐMessage(ctx context.Context, sel ast.SelectionSet, v Message) graphql.Marshaler {
@@ -2052,7 +2064,13 @@ func (ec *executionContext) unmarshalNString2string(ctx context.Context, v inter
 }
 
 func (ec *executionContext) marshalNString2string(ctx context.Context, sel ast.SelectionSet, v string) graphql.Marshaler {
-	return graphql.MarshalString(v)
+	res := graphql.MarshalString(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalNTime2timeᚐTime(ctx context.Context, v interface{}) (time.Time, error) {
@@ -2060,13 +2078,13 @@ func (ec *executionContext) unmarshalNTime2timeᚐTime(ctx context.Context, v in
 }
 
 func (ec *executionContext) marshalNTime2timeᚐTime(ctx context.Context, sel ast.SelectionSet, v time.Time) graphql.Marshaler {
-	if v.IsZero() {
+	res := graphql.MarshalTime(v)
+	if res == graphql.Null {
 		if !ec.HasError(graphql.GetResolverContext(ctx)) {
 			ec.Errorf(ctx, "must not be null")
 		}
-		return graphql.Null
 	}
-	return graphql.MarshalTime(v)
+	return res
 }
 
 func (ec *executionContext) marshalN__Directive2githubᚗcomᚋ99designsᚋgqlgenᚋgraphqlᚋintrospectionᚐDirective(ctx context.Context, sel ast.SelectionSet, v introspection.Directive) graphql.Marshaler {
@@ -2115,7 +2133,13 @@ func (ec *executionContext) unmarshalN__DirectiveLocation2string(ctx context.Con
 }
 
 func (ec *executionContext) marshalN__DirectiveLocation2string(ctx context.Context, sel ast.SelectionSet, v string) graphql.Marshaler {
-	return graphql.MarshalString(v)
+	res := graphql.MarshalString(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalN__DirectiveLocation2ᚕstring(ctx context.Context, v interface{}) ([]string, error) {
@@ -2280,7 +2304,13 @@ func (ec *executionContext) unmarshalN__TypeKind2string(ctx context.Context, v i
 }
 
 func (ec *executionContext) marshalN__TypeKind2string(ctx context.Context, sel ast.SelectionSet, v string) graphql.Marshaler {
-	return graphql.MarshalString(v)
+	res := graphql.MarshalString(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalOBoolean2bool(ctx context.Context, v interface{}) (bool, error) {
diff --git a/example/config/generated.go b/example/config/generated.go
index feb75209f15..15a322b7c48 100644
--- a/example/config/generated.go
+++ b/example/config/generated.go
@@ -1908,7 +1908,13 @@ func (ec *executionContext) unmarshalNBoolean2bool(ctx context.Context, v interf
 }
 
 func (ec *executionContext) marshalNBoolean2bool(ctx context.Context, sel ast.SelectionSet, v bool) graphql.Marshaler {
-	return graphql.MarshalBoolean(v)
+	res := graphql.MarshalBoolean(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalNID2string(ctx context.Context, v interface{}) (string, error) {
@@ -1916,7 +1922,13 @@ func (ec *executionContext) unmarshalNID2string(ctx context.Context, v interface
 }
 
 func (ec *executionContext) marshalNID2string(ctx context.Context, sel ast.SelectionSet, v string) graphql.Marshaler {
-	return graphql.MarshalID(v)
+	res := graphql.MarshalID(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalNInt2int(ctx context.Context, v interface{}) (int, error) {
@@ -1924,7 +1936,13 @@ func (ec *executionContext) unmarshalNInt2int(ctx context.Context, v interface{}
 }
 
 func (ec *executionContext) marshalNInt2int(ctx context.Context, sel ast.SelectionSet, v int) graphql.Marshaler {
-	return graphql.MarshalInt(v)
+	res := graphql.MarshalInt(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalNNewTodo2githubᚗcomᚋ99designsᚋgqlgenᚋexampleᚋconfigᚐNewTodo(ctx context.Context, v interface{}) (NewTodo, error) {
@@ -1936,7 +1954,13 @@ func (ec *executionContext) unmarshalNString2string(ctx context.Context, v inter
 }
 
 func (ec *executionContext) marshalNString2string(ctx context.Context, sel ast.SelectionSet, v string) graphql.Marshaler {
-	return graphql.MarshalString(v)
+	res := graphql.MarshalString(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) marshalNTodo2githubᚗcomᚋ99designsᚋgqlgenᚋexampleᚋconfigᚐTodo(ctx context.Context, sel ast.SelectionSet, v Todo) graphql.Marshaler {
@@ -2040,7 +2064,13 @@ func (ec *executionContext) unmarshalN__DirectiveLocation2string(ctx context.Con
 }
 
 func (ec *executionContext) marshalN__DirectiveLocation2string(ctx context.Context, sel ast.SelectionSet, v string) graphql.Marshaler {
-	return graphql.MarshalString(v)
+	res := graphql.MarshalString(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalN__DirectiveLocation2ᚕstring(ctx context.Context, v interface{}) ([]string, error) {
@@ -2205,7 +2235,13 @@ func (ec *executionContext) unmarshalN__TypeKind2string(ctx context.Context, v i
 }
 
 func (ec *executionContext) marshalN__TypeKind2string(ctx context.Context, sel ast.SelectionSet, v string) graphql.Marshaler {
-	return graphql.MarshalString(v)
+	res := graphql.MarshalString(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalOBoolean2bool(ctx context.Context, v interface{}) (bool, error) {
diff --git a/example/dataloader/generated.go b/example/dataloader/generated.go
index f469832466e..b4da41f3888 100644
--- a/example/dataloader/generated.go
+++ b/example/dataloader/generated.go
@@ -2168,7 +2168,13 @@ func (ec *executionContext) unmarshalNBoolean2bool(ctx context.Context, v interf
 }
 
 func (ec *executionContext) marshalNBoolean2bool(ctx context.Context, sel ast.SelectionSet, v bool) graphql.Marshaler {
-	return graphql.MarshalBoolean(v)
+	res := graphql.MarshalBoolean(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) marshalNCustomer2githubᚗcomᚋ99designsᚋgqlgenᚋexampleᚋdataloaderᚐCustomer(ctx context.Context, sel ast.SelectionSet, v Customer) graphql.Marshaler {
@@ -2180,7 +2186,13 @@ func (ec *executionContext) unmarshalNFloat2float64(ctx context.Context, v inter
 }
 
 func (ec *executionContext) marshalNFloat2float64(ctx context.Context, sel ast.SelectionSet, v float64) graphql.Marshaler {
-	return graphql.MarshalFloat(v)
+	res := graphql.MarshalFloat(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalNInt2int(ctx context.Context, v interface{}) (int, error) {
@@ -2188,7 +2200,13 @@ func (ec *executionContext) unmarshalNInt2int(ctx context.Context, v interface{}
 }
 
 func (ec *executionContext) marshalNInt2int(ctx context.Context, sel ast.SelectionSet, v int) graphql.Marshaler {
-	return graphql.MarshalInt(v)
+	res := graphql.MarshalInt(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) marshalNItem2githubᚗcomᚋ99designsᚋgqlgenᚋexampleᚋdataloaderᚐItem(ctx context.Context, sel ast.SelectionSet, v Item) graphql.Marshaler {
@@ -2204,7 +2222,13 @@ func (ec *executionContext) unmarshalNString2string(ctx context.Context, v inter
 }
 
 func (ec *executionContext) marshalNString2string(ctx context.Context, sel ast.SelectionSet, v string) graphql.Marshaler {
-	return graphql.MarshalString(v)
+	res := graphql.MarshalString(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalNTime2timeᚐTime(ctx context.Context, v interface{}) (time.Time, error) {
@@ -2212,13 +2236,13 @@ func (ec *executionContext) unmarshalNTime2timeᚐTime(ctx context.Context, v in
 }
 
 func (ec *executionContext) marshalNTime2timeᚐTime(ctx context.Context, sel ast.SelectionSet, v time.Time) graphql.Marshaler {
-	if v.IsZero() {
+	res := graphql.MarshalTime(v)
+	if res == graphql.Null {
 		if !ec.HasError(graphql.GetResolverContext(ctx)) {
 			ec.Errorf(ctx, "must not be null")
 		}
-		return graphql.Null
 	}
-	return graphql.MarshalTime(v)
+	return res
 }
 
 func (ec *executionContext) marshalN__Directive2githubᚗcomᚋ99designsᚋgqlgenᚋgraphqlᚋintrospectionᚐDirective(ctx context.Context, sel ast.SelectionSet, v introspection.Directive) graphql.Marshaler {
@@ -2267,7 +2291,13 @@ func (ec *executionContext) unmarshalN__DirectiveLocation2string(ctx context.Con
 }
 
 func (ec *executionContext) marshalN__DirectiveLocation2string(ctx context.Context, sel ast.SelectionSet, v string) graphql.Marshaler {
-	return graphql.MarshalString(v)
+	res := graphql.MarshalString(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalN__DirectiveLocation2ᚕstring(ctx context.Context, v interface{}) ([]string, error) {
@@ -2432,7 +2462,13 @@ func (ec *executionContext) unmarshalN__TypeKind2string(ctx context.Context, v i
 }
 
 func (ec *executionContext) marshalN__TypeKind2string(ctx context.Context, sel ast.SelectionSet, v string) graphql.Marshaler {
-	return graphql.MarshalString(v)
+	res := graphql.MarshalString(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) marshalOAddress2githubᚗcomᚋ99designsᚋgqlgenᚋexampleᚋdataloaderᚐAddress(ctx context.Context, sel ast.SelectionSet, v Address) graphql.Marshaler {
diff --git a/example/fileupload/generated.go b/example/fileupload/generated.go
index ae1109a2520..b1dd3a545eb 100644
--- a/example/fileupload/generated.go
+++ b/example/fileupload/generated.go
@@ -1915,7 +1915,13 @@ func (ec *executionContext) unmarshalNBoolean2bool(ctx context.Context, v interf
 }
 
 func (ec *executionContext) marshalNBoolean2bool(ctx context.Context, sel ast.SelectionSet, v bool) graphql.Marshaler {
-	return graphql.MarshalBoolean(v)
+	res := graphql.MarshalBoolean(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) marshalNFile2githubᚗcomᚋ99designsᚋgqlgenᚋexampleᚋfileuploadᚋmodelᚐFile(ctx context.Context, sel ast.SelectionSet, v model.File) graphql.Marshaler {
@@ -1974,7 +1980,13 @@ func (ec *executionContext) unmarshalNInt2int(ctx context.Context, v interface{}
 }
 
 func (ec *executionContext) marshalNInt2int(ctx context.Context, sel ast.SelectionSet, v int) graphql.Marshaler {
-	return graphql.MarshalInt(v)
+	res := graphql.MarshalInt(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalNString2string(ctx context.Context, v interface{}) (string, error) {
@@ -1982,7 +1994,13 @@ func (ec *executionContext) unmarshalNString2string(ctx context.Context, v inter
 }
 
 func (ec *executionContext) marshalNString2string(ctx context.Context, sel ast.SelectionSet, v string) graphql.Marshaler {
-	return graphql.MarshalString(v)
+	res := graphql.MarshalString(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalNUpload2githubᚗcomᚋ99designsᚋgqlgenᚋgraphqlᚐUpload(ctx context.Context, v interface{}) (graphql.Upload, error) {
@@ -1990,7 +2008,13 @@ func (ec *executionContext) unmarshalNUpload2githubᚗcomᚋ99designsᚋgqlgen
 }
 
 func (ec *executionContext) marshalNUpload2githubᚗcomᚋ99designsᚋgqlgenᚋgraphqlᚐUpload(ctx context.Context, sel ast.SelectionSet, v graphql.Upload) graphql.Marshaler {
-	return graphql.MarshalUpload(v)
+	res := graphql.MarshalUpload(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalNUpload2ᚕgithubᚗcomᚋ99designsᚋgqlgenᚋgraphqlᚐUpload(ctx context.Context, v interface{}) ([]graphql.Upload, error) {
@@ -2092,7 +2116,13 @@ func (ec *executionContext) unmarshalN__DirectiveLocation2string(ctx context.Con
 }
 
 func (ec *executionContext) marshalN__DirectiveLocation2string(ctx context.Context, sel ast.SelectionSet, v string) graphql.Marshaler {
-	return graphql.MarshalString(v)
+	res := graphql.MarshalString(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalN__DirectiveLocation2ᚕstring(ctx context.Context, v interface{}) ([]string, error) {
@@ -2257,7 +2287,13 @@ func (ec *executionContext) unmarshalN__TypeKind2string(ctx context.Context, v i
 }
 
 func (ec *executionContext) marshalN__TypeKind2string(ctx context.Context, sel ast.SelectionSet, v string) graphql.Marshaler {
-	return graphql.MarshalString(v)
+	res := graphql.MarshalString(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalOBoolean2bool(ctx context.Context, v interface{}) (bool, error) {
diff --git a/example/scalars/generated.go b/example/scalars/generated.go
index 9a70016302b..5b6cfc70955 100644
--- a/example/scalars/generated.go
+++ b/example/scalars/generated.go
@@ -2026,7 +2026,13 @@ func (ec *executionContext) unmarshalNBoolean2bool(ctx context.Context, v interf
 }
 
 func (ec *executionContext) marshalNBoolean2bool(ctx context.Context, sel ast.SelectionSet, v bool) graphql.Marshaler {
-	return graphql.MarshalBoolean(v)
+	res := graphql.MarshalBoolean(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalNID2githubᚗcomᚋ99designsᚋgqlgenᚋexampleᚋscalarsᚋexternalᚐObjectID(ctx context.Context, v interface{}) (external.ObjectID, error) {
@@ -2034,7 +2040,13 @@ func (ec *executionContext) unmarshalNID2githubᚗcomᚋ99designsᚋgqlgenᚋexa
 }
 
 func (ec *executionContext) marshalNID2githubᚗcomᚋ99designsᚋgqlgenᚋexampleᚋscalarsᚋexternalᚐObjectID(ctx context.Context, sel ast.SelectionSet, v external.ObjectID) graphql.Marshaler {
-	return model.MarshalID(v)
+	res := model.MarshalID(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalNPoint2githubᚗcomᚋ99designsᚋgqlgenᚋexampleᚋscalarsᚋmodelᚐPoint(ctx context.Context, v interface{}) (model.Point, error) {
@@ -2069,7 +2081,13 @@ func (ec *executionContext) unmarshalNString2string(ctx context.Context, v inter
 }
 
 func (ec *executionContext) marshalNString2string(ctx context.Context, sel ast.SelectionSet, v string) graphql.Marshaler {
-	return graphql.MarshalString(v)
+	res := graphql.MarshalString(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) marshalNUser2githubᚗcomᚋ99designsᚋgqlgenᚋexampleᚋscalarsᚋmodelᚐUser(ctx context.Context, sel ast.SelectionSet, v model.User) graphql.Marshaler {
@@ -2159,7 +2177,13 @@ func (ec *executionContext) unmarshalN__DirectiveLocation2string(ctx context.Con
 }
 
 func (ec *executionContext) marshalN__DirectiveLocation2string(ctx context.Context, sel ast.SelectionSet, v string) graphql.Marshaler {
-	return graphql.MarshalString(v)
+	res := graphql.MarshalString(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalN__DirectiveLocation2ᚕstring(ctx context.Context, v interface{}) ([]string, error) {
@@ -2324,7 +2348,13 @@ func (ec *executionContext) unmarshalN__TypeKind2string(ctx context.Context, v i
 }
 
 func (ec *executionContext) marshalN__TypeKind2string(ctx context.Context, sel ast.SelectionSet, v string) graphql.Marshaler {
-	return graphql.MarshalString(v)
+	res := graphql.MarshalString(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) marshalOAddress2githubᚗcomᚋ99designsᚋgqlgenᚋexampleᚋscalarsᚋmodelᚐAddress(ctx context.Context, sel ast.SelectionSet, v model.Address) graphql.Marshaler {
@@ -2436,9 +2466,6 @@ func (ec *executionContext) unmarshalOTimestamp2timeᚐTime(ctx context.Context,
 }
 
 func (ec *executionContext) marshalOTimestamp2timeᚐTime(ctx context.Context, sel ast.SelectionSet, v time.Time) graphql.Marshaler {
-	if v.IsZero() {
-		return graphql.Null
-	}
 	return model.MarshalTimestamp(v)
 }
 
diff --git a/example/selection/generated.go b/example/selection/generated.go
index f0f830e38d4..e7315d522c6 100644
--- a/example/selection/generated.go
+++ b/example/selection/generated.go
@@ -1786,7 +1786,13 @@ func (ec *executionContext) unmarshalNBoolean2bool(ctx context.Context, v interf
 }
 
 func (ec *executionContext) marshalNBoolean2bool(ctx context.Context, sel ast.SelectionSet, v bool) graphql.Marshaler {
-	return graphql.MarshalBoolean(v)
+	res := graphql.MarshalBoolean(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) marshalNEvent2githubᚗcomᚋ99designsᚋgqlgenᚋexampleᚋselectionᚐEvent(ctx context.Context, sel ast.SelectionSet, v Event) graphql.Marshaler {
@@ -1798,7 +1804,13 @@ func (ec *executionContext) unmarshalNString2string(ctx context.Context, v inter
 }
 
 func (ec *executionContext) marshalNString2string(ctx context.Context, sel ast.SelectionSet, v string) graphql.Marshaler {
-	return graphql.MarshalString(v)
+	res := graphql.MarshalString(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalNTime2timeᚐTime(ctx context.Context, v interface{}) (time.Time, error) {
@@ -1806,13 +1818,13 @@ func (ec *executionContext) unmarshalNTime2timeᚐTime(ctx context.Context, v in
 }
 
 func (ec *executionContext) marshalNTime2timeᚐTime(ctx context.Context, sel ast.SelectionSet, v time.Time) graphql.Marshaler {
-	if v.IsZero() {
+	res := graphql.MarshalTime(v)
+	if res == graphql.Null {
 		if !ec.HasError(graphql.GetResolverContext(ctx)) {
 			ec.Errorf(ctx, "must not be null")
 		}
-		return graphql.Null
 	}
-	return graphql.MarshalTime(v)
+	return res
 }
 
 func (ec *executionContext) marshalN__Directive2githubᚗcomᚋ99designsᚋgqlgenᚋgraphqlᚋintrospectionᚐDirective(ctx context.Context, sel ast.SelectionSet, v introspection.Directive) graphql.Marshaler {
@@ -1861,7 +1873,13 @@ func (ec *executionContext) unmarshalN__DirectiveLocation2string(ctx context.Con
 }
 
 func (ec *executionContext) marshalN__DirectiveLocation2string(ctx context.Context, sel ast.SelectionSet, v string) graphql.Marshaler {
-	return graphql.MarshalString(v)
+	res := graphql.MarshalString(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalN__DirectiveLocation2ᚕstring(ctx context.Context, v interface{}) ([]string, error) {
@@ -2026,7 +2044,13 @@ func (ec *executionContext) unmarshalN__TypeKind2string(ctx context.Context, v i
 }
 
 func (ec *executionContext) marshalN__TypeKind2string(ctx context.Context, sel ast.SelectionSet, v string) graphql.Marshaler {
-	return graphql.MarshalString(v)
+	res := graphql.MarshalString(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalOBoolean2bool(ctx context.Context, v interface{}) (bool, error) {
diff --git a/example/starwars/generated/exec.go b/example/starwars/generated/exec.go
index 436041e4b59..3de5c9922aa 100644
--- a/example/starwars/generated/exec.go
+++ b/example/starwars/generated/exec.go
@@ -3707,7 +3707,13 @@ func (ec *executionContext) unmarshalNBoolean2bool(ctx context.Context, v interf
 }
 
 func (ec *executionContext) marshalNBoolean2bool(ctx context.Context, sel ast.SelectionSet, v bool) graphql.Marshaler {
-	return graphql.MarshalBoolean(v)
+	res := graphql.MarshalBoolean(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) marshalNCharacter2githubᚗcomᚋ99designsᚋgqlgenᚋexampleᚋstarwarsᚋmodelsᚐCharacter(ctx context.Context, sel ast.SelectionSet, v models.Character) graphql.Marshaler {
@@ -3785,7 +3791,13 @@ func (ec *executionContext) unmarshalNFloat2float64(ctx context.Context, v inter
 }
 
 func (ec *executionContext) marshalNFloat2float64(ctx context.Context, sel ast.SelectionSet, v float64) graphql.Marshaler {
-	return graphql.MarshalFloat(v)
+	res := graphql.MarshalFloat(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) marshalNFriendsConnection2githubᚗcomᚋ99designsᚋgqlgenᚋexampleᚋstarwarsᚋmodelsᚐFriendsConnection(ctx context.Context, sel ast.SelectionSet, v models.FriendsConnection) graphql.Marshaler {
@@ -3811,7 +3823,13 @@ func (ec *executionContext) unmarshalNID2string(ctx context.Context, v interface
 }
 
 func (ec *executionContext) marshalNID2string(ctx context.Context, sel ast.SelectionSet, v string) graphql.Marshaler {
-	return graphql.MarshalID(v)
+	res := graphql.MarshalID(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalNInt2int(ctx context.Context, v interface{}) (int, error) {
@@ -3819,7 +3837,13 @@ func (ec *executionContext) unmarshalNInt2int(ctx context.Context, v interface{}
 }
 
 func (ec *executionContext) marshalNInt2int(ctx context.Context, sel ast.SelectionSet, v int) graphql.Marshaler {
-	return graphql.MarshalInt(v)
+	res := graphql.MarshalInt(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalNInt2ᚕint(ctx context.Context, v interface{}) ([]int, error) {
@@ -3979,7 +4003,13 @@ func (ec *executionContext) unmarshalNString2string(ctx context.Context, v inter
 }
 
 func (ec *executionContext) marshalNString2string(ctx context.Context, sel ast.SelectionSet, v string) graphql.Marshaler {
-	return graphql.MarshalString(v)
+	res := graphql.MarshalString(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) marshalN__Directive2githubᚗcomᚋ99designsᚋgqlgenᚋgraphqlᚋintrospectionᚐDirective(ctx context.Context, sel ast.SelectionSet, v introspection.Directive) graphql.Marshaler {
@@ -4028,7 +4058,13 @@ func (ec *executionContext) unmarshalN__DirectiveLocation2string(ctx context.Con
 }
 
 func (ec *executionContext) marshalN__DirectiveLocation2string(ctx context.Context, sel ast.SelectionSet, v string) graphql.Marshaler {
-	return graphql.MarshalString(v)
+	res := graphql.MarshalString(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalN__DirectiveLocation2ᚕstring(ctx context.Context, v interface{}) ([]string, error) {
@@ -4193,7 +4229,13 @@ func (ec *executionContext) unmarshalN__TypeKind2string(ctx context.Context, v i
 }
 
 func (ec *executionContext) marshalN__TypeKind2string(ctx context.Context, sel ast.SelectionSet, v string) graphql.Marshaler {
-	return graphql.MarshalString(v)
+	res := graphql.MarshalString(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalOBoolean2bool(ctx context.Context, v interface{}) (bool, error) {
@@ -4517,9 +4559,6 @@ func (ec *executionContext) unmarshalOTime2timeᚐTime(ctx context.Context, v in
 }
 
 func (ec *executionContext) marshalOTime2timeᚐTime(ctx context.Context, sel ast.SelectionSet, v time.Time) graphql.Marshaler {
-	if v.IsZero() {
-		return graphql.Null
-	}
 	return graphql.MarshalTime(v)
 }
 
diff --git a/example/todo/generated.go b/example/todo/generated.go
index e8c39541d76..ec150f1a6a0 100644
--- a/example/todo/generated.go
+++ b/example/todo/generated.go
@@ -1939,7 +1939,13 @@ func (ec *executionContext) unmarshalNBoolean2bool(ctx context.Context, v interf
 }
 
 func (ec *executionContext) marshalNBoolean2bool(ctx context.Context, sel ast.SelectionSet, v bool) graphql.Marshaler {
-	return graphql.MarshalBoolean(v)
+	res := graphql.MarshalBoolean(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalNID2int(ctx context.Context, v interface{}) (int, error) {
@@ -1947,7 +1953,13 @@ func (ec *executionContext) unmarshalNID2int(ctx context.Context, v interface{})
 }
 
 func (ec *executionContext) marshalNID2int(ctx context.Context, sel ast.SelectionSet, v int) graphql.Marshaler {
-	return graphql.MarshalIntID(v)
+	res := graphql.MarshalIntID(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalNMap2map(ctx context.Context, v interface{}) (map[string]interface{}, error) {
@@ -1964,7 +1976,13 @@ func (ec *executionContext) marshalNMap2map(ctx context.Context, sel ast.Selecti
 		}
 		return graphql.Null
 	}
-	return graphql.MarshalMap(v)
+	res := graphql.MarshalMap(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalNRole2githubᚗcomᚋ99designsᚋgqlgenᚋexampleᚋtodoᚐRole(ctx context.Context, v interface{}) (Role, error) {
@@ -1981,7 +1999,13 @@ func (ec *executionContext) unmarshalNString2string(ctx context.Context, v inter
 }
 
 func (ec *executionContext) marshalNString2string(ctx context.Context, sel ast.SelectionSet, v string) graphql.Marshaler {
-	return graphql.MarshalString(v)
+	res := graphql.MarshalString(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) marshalNTodo2githubᚗcomᚋ99designsᚋgqlgenᚋexampleᚋtodoᚐTodo(ctx context.Context, sel ast.SelectionSet, v Todo) graphql.Marshaler {
@@ -2085,7 +2109,13 @@ func (ec *executionContext) unmarshalN__DirectiveLocation2string(ctx context.Con
 }
 
 func (ec *executionContext) marshalN__DirectiveLocation2string(ctx context.Context, sel ast.SelectionSet, v string) graphql.Marshaler {
-	return graphql.MarshalString(v)
+	res := graphql.MarshalString(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalN__DirectiveLocation2ᚕstring(ctx context.Context, v interface{}) ([]string, error) {
@@ -2250,7 +2280,13 @@ func (ec *executionContext) unmarshalN__TypeKind2string(ctx context.Context, v i
 }
 
 func (ec *executionContext) marshalN__TypeKind2string(ctx context.Context, sel ast.SelectionSet, v string) graphql.Marshaler {
-	return graphql.MarshalString(v)
+	res := graphql.MarshalString(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalOBoolean2bool(ctx context.Context, v interface{}) (bool, error) {
diff --git a/example/type-system-extension/generated.go b/example/type-system-extension/generated.go
index 7a35f3e20e4..ea5a77c238e 100644
--- a/example/type-system-extension/generated.go
+++ b/example/type-system-extension/generated.go
@@ -1956,7 +1956,13 @@ func (ec *executionContext) unmarshalNBoolean2bool(ctx context.Context, v interf
 }
 
 func (ec *executionContext) marshalNBoolean2bool(ctx context.Context, sel ast.SelectionSet, v bool) graphql.Marshaler {
-	return graphql.MarshalBoolean(v)
+	res := graphql.MarshalBoolean(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalNID2string(ctx context.Context, v interface{}) (string, error) {
@@ -1964,7 +1970,13 @@ func (ec *executionContext) unmarshalNID2string(ctx context.Context, v interface
 }
 
 func (ec *executionContext) marshalNID2string(ctx context.Context, sel ast.SelectionSet, v string) graphql.Marshaler {
-	return graphql.MarshalID(v)
+	res := graphql.MarshalID(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalNState2githubᚗcomᚋ99designsᚋgqlgenᚋexampleᚋtypeᚑsystemᚑextensionᚐState(ctx context.Context, v interface{}) (State, error) {
@@ -1981,7 +1993,13 @@ func (ec *executionContext) unmarshalNString2string(ctx context.Context, v inter
 }
 
 func (ec *executionContext) marshalNString2string(ctx context.Context, sel ast.SelectionSet, v string) graphql.Marshaler {
-	return graphql.MarshalString(v)
+	res := graphql.MarshalString(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) marshalNTodo2githubᚗcomᚋ99designsᚋgqlgenᚋexampleᚋtypeᚑsystemᚑextensionᚐTodo(ctx context.Context, sel ast.SelectionSet, v Todo) graphql.Marshaler {
@@ -2085,7 +2103,13 @@ func (ec *executionContext) unmarshalN__DirectiveLocation2string(ctx context.Con
 }
 
 func (ec *executionContext) marshalN__DirectiveLocation2string(ctx context.Context, sel ast.SelectionSet, v string) graphql.Marshaler {
-	return graphql.MarshalString(v)
+	res := graphql.MarshalString(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalN__DirectiveLocation2ᚕstring(ctx context.Context, v interface{}) ([]string, error) {
@@ -2250,7 +2274,13 @@ func (ec *executionContext) unmarshalN__TypeKind2string(ctx context.Context, v i
 }
 
 func (ec *executionContext) marshalN__TypeKind2string(ctx context.Context, sel ast.SelectionSet, v string) graphql.Marshaler {
-	return graphql.MarshalString(v)
+	res := graphql.MarshalString(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalOBoolean2bool(ctx context.Context, v interface{}) (bool, error) {
diff --git a/graphql/time.go b/graphql/time.go
index 4f448560274..9945f3fbfda 100644
--- a/graphql/time.go
+++ b/graphql/time.go
@@ -8,6 +8,10 @@ import (
 )
 
 func MarshalTime(t time.Time) Marshaler {
+	if t.IsZero() {
+		return Null
+	}
+
 	return WriterFunc(func(w io.Writer) {
 		io.WriteString(w, strconv.Quote(t.Format(time.RFC3339)))
 	})
diff --git a/integration/generated.go b/integration/generated.go
index 4405c7b5103..46881f41436 100644
--- a/integration/generated.go
+++ b/integration/generated.go
@@ -2191,7 +2191,13 @@ func (ec *executionContext) unmarshalNBoolean2bool(ctx context.Context, v interf
 }
 
 func (ec *executionContext) marshalNBoolean2bool(ctx context.Context, sel ast.SelectionSet, v bool) graphql.Marshaler {
-	return graphql.MarshalBoolean(v)
+	res := graphql.MarshalBoolean(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalNDateFilter2githubᚗcomᚋ99designsᚋgqlgenᚋintegrationᚋmodelsᚑgoᚐDateFilter(ctx context.Context, v interface{}) (models.DateFilter, error) {
@@ -2217,7 +2223,13 @@ func (ec *executionContext) unmarshalNInt2int(ctx context.Context, v interface{}
 }
 
 func (ec *executionContext) marshalNInt2int(ctx context.Context, sel ast.SelectionSet, v int) graphql.Marshaler {
-	return graphql.MarshalInt(v)
+	res := graphql.MarshalInt(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalNString2string(ctx context.Context, v interface{}) (string, error) {
@@ -2225,7 +2237,13 @@ func (ec *executionContext) unmarshalNString2string(ctx context.Context, v inter
 }
 
 func (ec *executionContext) marshalNString2string(ctx context.Context, sel ast.SelectionSet, v string) graphql.Marshaler {
-	return graphql.MarshalString(v)
+	res := graphql.MarshalString(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalNString2ᚕstring(ctx context.Context, v interface{}) ([]string, error) {
@@ -2303,7 +2321,13 @@ func (ec *executionContext) unmarshalN__DirectiveLocation2string(ctx context.Con
 }
 
 func (ec *executionContext) marshalN__DirectiveLocation2string(ctx context.Context, sel ast.SelectionSet, v string) graphql.Marshaler {
-	return graphql.MarshalString(v)
+	res := graphql.MarshalString(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalN__DirectiveLocation2ᚕstring(ctx context.Context, v interface{}) ([]string, error) {
@@ -2468,7 +2492,13 @@ func (ec *executionContext) unmarshalN__TypeKind2string(ctx context.Context, v i
 }
 
 func (ec *executionContext) marshalN__TypeKind2string(ctx context.Context, sel ast.SelectionSet, v string) graphql.Marshaler {
-	return graphql.MarshalString(v)
+	res := graphql.MarshalString(v)
+	if res == graphql.Null {
+		if !ec.HasError(graphql.GetResolverContext(ctx)) {
+			ec.Errorf(ctx, "must not be null")
+		}
+	}
+	return res
 }
 
 func (ec *executionContext) unmarshalOBoolean2bool(ctx context.Context, v interface{}) (bool, error) {