diff --git a/third-party/thrift/src/thrift/compiler/generate/templates/go/types/struct_method_new.mustache b/third-party/thrift/src/thrift/compiler/generate/templates/go/types/struct_method_new.mustache
index 1d608a526e4b3d..775e0c7ceadc00 100644
--- a/third-party/thrift/src/thrift/compiler/generate/templates/go/types/struct_method_new.mustache
+++ b/third-party/thrift/src/thrift/compiler/generate/templates/go/types/struct_method_new.mustache
@@ -21,6 +21,7 @@
 }}
 func {{struct:go_qualified_new_func}}() *{{struct:go_name}} {
     return (&{{struct:go_name}}{}){{!
+      }}{{^struct:union?}}{{!
       }}{{#struct:fields}}{{!
 
         // Fields with given default values.
@@ -46,6 +47,7 @@ func {{struct:go_qualified_new_func}}() *{{struct:go_name}} {
         }}){{/field:optional?}}{{!
         }}{{/field:value}}{{!
 
-      }}{{/struct:fields}}
+      }}{{/struct:fields}}{{!
+      }}{{/struct:union?}}
 }
 {{!newline}}
diff --git a/third-party/thrift/src/thrift/compiler/test/fixtures/adapter/gen-go_mstch/module/types.go b/third-party/thrift/src/thrift/compiler/test/fixtures/adapter/gen-go_mstch/module/types.go
index 880241ee2e33f0..adfa6763468d6f 100644
--- a/third-party/thrift/src/thrift/compiler/test/fixtures/adapter/gen-go_mstch/module/types.go
+++ b/third-party/thrift/src/thrift/compiler/test/fixtures/adapter/gen-go_mstch/module/types.go
@@ -2032,12 +2032,7 @@ type Baz struct {
 var _ thrift.Struct = &Baz{}
 
 func NewBaz() *Baz {
-    return (&Baz{}).
-        SetIntFieldNonCompat(0).
-        SetSetFieldNonCompat(NewSetWithAdapter()).
-        SetMapFieldNonCompat(make(map[string]ListWithElemAdapterWithAdapter)).
-        SetBinaryFieldNonCompat([]byte("")).
-        SetLongFieldNonCompat(NewMyI64())
+    return (&Baz{})
 }
 
 func (x *Baz) GetIntFieldNonCompat() *int32 {
@@ -7303,9 +7298,7 @@ type AdaptTestUnion struct {
 var _ thrift.Struct = &AdaptTestUnion{}
 
 func NewAdaptTestUnion() *AdaptTestUnion {
-    return (&AdaptTestUnion{}).
-        SetDelayNonCompat(NewDurationMs()).
-        SetCustomNonCompat(NewCustomProtocolType())
+    return (&AdaptTestUnion{})
 }
 
 func (x *AdaptTestUnion) GetDelayNonCompat() *DurationMs {
diff --git a/third-party/thrift/src/thrift/compiler/test/fixtures/basic/gen-go_mstch/module/types.go b/third-party/thrift/src/thrift/compiler/test/fixtures/basic/gen-go_mstch/module/types.go
index 04b2d588a3abed..7ca972b4b05296 100644
--- a/third-party/thrift/src/thrift/compiler/test/fixtures/basic/gen-go_mstch/module/types.go
+++ b/third-party/thrift/src/thrift/compiler/test/fixtures/basic/gen-go_mstch/module/types.go
@@ -894,11 +894,7 @@ type MyUnion struct {
 var _ thrift.Struct = &MyUnion{}
 
 func NewMyUnion() *MyUnion {
-    return (&MyUnion{}).
-        SetMyEnumNonCompat(0).
-        SetMyStructNonCompat(*NewMyStruct()).
-        SetMyDataItemNonCompat(*NewMyDataItem()).
-        SetFloatSetNonCompat(make([]float32, 0))
+    return (&MyUnion{})
 }
 
 func (x *MyUnion) GetMyEnumNonCompat() *MyEnum {
@@ -1475,8 +1471,7 @@ type UnionToBeRenamed struct {
 var _ thrift.Struct = &UnionToBeRenamed{}
 
 func NewUnionToBeRenamed() *UnionToBeRenamed {
-    return (&UnionToBeRenamed{}).
-        SetReservedFieldNonCompat(0)
+    return (&UnionToBeRenamed{})
 }
 
 func (x *UnionToBeRenamed) GetReservedFieldNonCompat() *int32 {
diff --git a/third-party/thrift/src/thrift/compiler/test/fixtures/complex-union/gen-go_mstch/module/types.go b/third-party/thrift/src/thrift/compiler/test/fixtures/complex-union/gen-go_mstch/module/types.go
index 81371c1d0ff0c7..9d17f8d0e08d86 100644
--- a/third-party/thrift/src/thrift/compiler/test/fixtures/complex-union/gen-go_mstch/module/types.go
+++ b/third-party/thrift/src/thrift/compiler/test/fixtures/complex-union/gen-go_mstch/module/types.go
@@ -99,13 +99,7 @@ type ComplexUnion struct {
 var _ thrift.Struct = &ComplexUnion{}
 
 func NewComplexUnion() *ComplexUnion {
-    return (&ComplexUnion{}).
-        SetIntValueNonCompat(0).
-        SetStringValueNonCompat("").
-        SetIntListValueNonCompat(make([]int64, 0)).
-        SetStringListValueNonCompat(make([]string, 0)).
-        SetTypedefValueNonCompat(NewContainerTypedef()).
-        SetStringRefNonCompat("")
+    return (&ComplexUnion{})
 }
 
 func (x *ComplexUnion) GetIntValueNonCompat() *int64 {
@@ -699,9 +693,7 @@ type ListUnion struct {
 var _ thrift.Struct = &ListUnion{}
 
 func NewListUnion() *ListUnion {
-    return (&ListUnion{}).
-        SetIntListValueNonCompat(make([]int64, 0)).
-        SetStringListValueNonCompat(make([]string, 0))
+    return (&ListUnion{})
 }
 
 func (x *ListUnion) GetIntListValueNonCompat() []int64 {
@@ -997,9 +989,7 @@ type DataUnion struct {
 var _ thrift.Struct = &DataUnion{}
 
 func NewDataUnion() *DataUnion {
-    return (&DataUnion{}).
-        SetBinaryDataNonCompat([]byte("")).
-        SetStringDataNonCompat("")
+    return (&DataUnion{})
 }
 
 func (x *DataUnion) GetBinaryDataNonCompat() []byte {
@@ -1510,9 +1500,7 @@ type ValUnion struct {
 var _ thrift.Struct = &ValUnion{}
 
 func NewValUnion() *ValUnion {
-    return (&ValUnion{}).
-        SetV1NonCompat(*NewVal()).
-        SetV2NonCompat(*NewVal())
+    return (&ValUnion{})
 }
 
 func (x *ValUnion) GetV1NonCompat() *Val {
@@ -1774,9 +1762,7 @@ type VirtualComplexUnion struct {
 var _ thrift.Struct = &VirtualComplexUnion{}
 
 func NewVirtualComplexUnion() *VirtualComplexUnion {
-    return (&VirtualComplexUnion{}).
-        SetThingOneNonCompat("").
-        SetThingTwoNonCompat("")
+    return (&VirtualComplexUnion{})
 }
 
 func (x *VirtualComplexUnion) GetThingOneNonCompat() *string {
@@ -2158,8 +2144,7 @@ type NonCopyableUnion struct {
 var _ thrift.Struct = &NonCopyableUnion{}
 
 func NewNonCopyableUnion() *NonCopyableUnion {
-    return (&NonCopyableUnion{}).
-        SetSNonCompat(*NewNonCopyableStruct())
+    return (&NonCopyableUnion{})
 }
 
 func (x *NonCopyableUnion) GetSNonCompat() *NonCopyableStruct {
diff --git a/third-party/thrift/src/thrift/compiler/test/fixtures/constants/gen-go_mstch/module/types.go b/third-party/thrift/src/thrift/compiler/test/fixtures/constants/gen-go_mstch/module/types.go
index e0f971d883ec2f..c74d9ea34dcc97 100644
--- a/third-party/thrift/src/thrift/compiler/test/fixtures/constants/gen-go_mstch/module/types.go
+++ b/third-party/thrift/src/thrift/compiler/test/fixtures/constants/gen-go_mstch/module/types.go
@@ -2111,9 +2111,7 @@ type Union1 struct {
 var _ thrift.Struct = &Union1{}
 
 func NewUnion1() *Union1 {
-    return (&Union1{}).
-        SetINonCompat(0).
-        SetDNonCompat(0.0)
+    return (&Union1{})
 }
 
 func (x *Union1) GetINonCompat() *int32 {
@@ -2359,11 +2357,7 @@ type Union2 struct {
 var _ thrift.Struct = &Union2{}
 
 func NewUnion2() *Union2 {
-    return (&Union2{}).
-        SetINonCompat(0).
-        SetDNonCompat(0.0).
-        SetSNonCompat(*NewStruct1()).
-        SetUNonCompat(*NewUnion1())
+    return (&Union2{})
 }
 
 func (x *Union2) GetINonCompat() *int32 {
diff --git a/third-party/thrift/src/thrift/compiler/test/fixtures/doctext/gen-go_mstch/module/types.go b/third-party/thrift/src/thrift/compiler/test/fixtures/doctext/gen-go_mstch/module/types.go
index 47828bd4c7e6a1..23eb87fd639f64 100644
--- a/third-party/thrift/src/thrift/compiler/test/fixtures/doctext/gen-go_mstch/module/types.go
+++ b/third-party/thrift/src/thrift/compiler/test/fixtures/doctext/gen-go_mstch/module/types.go
@@ -264,9 +264,7 @@ type U struct {
 var _ thrift.Struct = &U{}
 
 func NewU() *U {
-    return (&U{}).
-        SetINonCompat(0).
-        SetSNonCompat("")
+    return (&U{})
 }
 
 func (x *U) GetINonCompat() *int32 {
diff --git a/third-party/thrift/src/thrift/compiler/test/fixtures/no-legacy-apis/gen-go_mstch/module/types.go b/third-party/thrift/src/thrift/compiler/test/fixtures/no-legacy-apis/gen-go_mstch/module/types.go
index e0fc5294593b86..bd202a6ec07ba1 100644
--- a/third-party/thrift/src/thrift/compiler/test/fixtures/no-legacy-apis/gen-go_mstch/module/types.go
+++ b/third-party/thrift/src/thrift/compiler/test/fixtures/no-legacy-apis/gen-go_mstch/module/types.go
@@ -278,9 +278,7 @@ type MyUnion struct {
 var _ thrift.Struct = &MyUnion{}
 
 func NewMyUnion() *MyUnion {
-    return (&MyUnion{}).
-        SetMyEnumNonCompat(0).
-        SetMyDataItemNonCompat(*NewMyStruct())
+    return (&MyUnion{})
 }
 
 func (x *MyUnion) GetMyEnumNonCompat() *MyEnum {
diff --git a/third-party/thrift/src/thrift/compiler/test/fixtures/patch/gen-go_mstch/module/types.go b/third-party/thrift/src/thrift/compiler/test/fixtures/patch/gen-go_mstch/module/types.go
index 90e1eb2438f07e..a10765a69eb390 100644
--- a/third-party/thrift/src/thrift/compiler/test/fixtures/patch/gen-go_mstch/module/types.go
+++ b/third-party/thrift/src/thrift/compiler/test/fixtures/patch/gen-go_mstch/module/types.go
@@ -474,8 +474,7 @@ type InnerUnion struct {
 var _ thrift.Struct = &InnerUnion{}
 
 func NewInnerUnion() *InnerUnion {
-    return (&InnerUnion{}).
-        SetInnerOptionNonCompat([]byte(""))
+    return (&InnerUnion{})
 }
 
 func (x *InnerUnion) GetInnerOptionNonCompat() []byte {
@@ -642,10 +641,7 @@ type MyUnion struct {
 var _ thrift.Struct = &MyUnion{}
 
 func NewMyUnion() *MyUnion {
-    return (&MyUnion{}).
-        SetOption1NonCompat("").
-        SetOption2NonCompat(0).
-        SetOption3NonCompat(*NewInnerUnion())
+    return (&MyUnion{})
 }
 
 func (x *MyUnion) GetOption1NonCompat() *string {
diff --git a/third-party/thrift/src/thrift/compiler/test/fixtures/patch/gen-go_mstch/thrift/lib/thrift/standard/types.go b/third-party/thrift/src/thrift/compiler/test/fixtures/patch/gen-go_mstch/thrift/lib/thrift/standard/types.go
index e5c680e1425272..f9e52d0878f8f7 100644
--- a/third-party/thrift/src/thrift/compiler/test/fixtures/patch/gen-go_mstch/thrift/lib/thrift/standard/types.go
+++ b/third-party/thrift/src/thrift/compiler/test/fixtures/patch/gen-go_mstch/thrift/lib/thrift/standard/types.go
@@ -225,9 +225,7 @@ type TypeUri struct {
 var _ thrift.Struct = &TypeUri{}
 
 func NewTypeUri() *TypeUri {
-    return (&TypeUri{}).
-        SetUriNonCompat(NewUri()).
-        SetTypeHashPrefixSha2_256NonCompat(NewByteString())
+    return (&TypeUri{})
 }
 
 func (x *TypeUri) GetUriNonCompat() *Uri {
@@ -485,24 +483,7 @@ type TypeName struct {
 var _ thrift.Struct = &TypeName{}
 
 func NewTypeName() *TypeName {
-    return (&TypeName{}).
-        SetBoolTypeNonCompat(0).
-        SetByteTypeNonCompat(0).
-        SetI16TypeNonCompat(0).
-        SetI32TypeNonCompat(0).
-        SetI64TypeNonCompat(0).
-        SetFloatTypeNonCompat(0).
-        SetDoubleTypeNonCompat(0).
-        SetStringTypeNonCompat(0).
-        SetBinaryTypeNonCompat(0).
-        SetEnumTypeNonCompat(*NewTypeUri()).
-        SetTypedefTypeNonCompat(*NewTypeUri()).
-        SetStructTypeNonCompat(*NewTypeUri()).
-        SetUnionTypeNonCompat(*NewTypeUri()).
-        SetExceptionTypeNonCompat(*NewTypeUri()).
-        SetListTypeNonCompat(0).
-        SetSetTypeNonCompat(0).
-        SetMapTypeNonCompat(0)
+    return (&TypeName{})
 }
 
 func (x *TypeName) GetBoolTypeNonCompat() *Void {
diff --git a/third-party/thrift/src/thrift/compiler/test/fixtures/terse_write/gen-go_mstch/terse_write/types.go b/third-party/thrift/src/thrift/compiler/test/fixtures/terse_write/gen-go_mstch/terse_write/types.go
index ebd546fb310e4d..adb76a295e4538 100644
--- a/third-party/thrift/src/thrift/compiler/test/fixtures/terse_write/gen-go_mstch/terse_write/types.go
+++ b/third-party/thrift/src/thrift/compiler/test/fixtures/terse_write/gen-go_mstch/terse_write/types.go
@@ -202,21 +202,7 @@ type MyUnion struct {
 var _ thrift.Struct = &MyUnion{}
 
 func NewMyUnion() *MyUnion {
-    return (&MyUnion{}).
-        SetBoolFieldNonCompat(false).
-        SetByteFieldNonCompat(0).
-        SetShortFieldNonCompat(0).
-        SetIntFieldNonCompat(0).
-        SetLongFieldNonCompat(0).
-        SetFloatFieldNonCompat(0.0).
-        SetDoubleFieldNonCompat(0.0).
-        SetStringFieldNonCompat("").
-        SetBinaryFieldNonCompat([]byte("")).
-        SetEnumFieldNonCompat(0).
-        SetListFieldNonCompat(make([]int16, 0)).
-        SetSetFieldNonCompat(make([]int16, 0)).
-        SetMapFieldNonCompat(make(map[int16]int16)).
-        SetStructFieldNonCompat(*NewMyStruct())
+    return (&MyUnion{})
 }
 
 func (x *MyUnion) GetBoolFieldNonCompat() *bool {