diff --git a/cmd/generate-bindings/solana/anchor-go/generator/complex_enum_encode_test.go b/cmd/generate-bindings/solana/anchor-go/generator/complex_enum_encode_test.go
new file mode 100644
index 00000000..b92501e1
--- /dev/null
+++ b/cmd/generate-bindings/solana/anchor-go/generator/complex_enum_encode_test.go
@@ -0,0 +1,86 @@
+//nolint:all // Forked from anchor-go generator, maintaining original code structure
+package generator
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/dave/jennifer/jen"
+	"github.com/gagliardetto/anchor-go/idl"
+	"github.com/gagliardetto/anchor-go/idl/idltype"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// complexEnumIDL returns a minimal IDL containing a two-variant complex enum
+// ("MyAction") suitable for exercising gen_complexEnum codegen.
+func complexEnumIDL() *idl.Idl {
+	enumType := &idl.IdlTypeDefTyEnum{
+		Variants: idl.VariantSlice{
+			{
+				Name: "Transfer",
+				Fields: idl.Some[idl.IdlDefinedFields](idl.IdlDefinedFieldsNamed{
+					{Name: "amount", Ty: &idltype.U64{}},
+				}),
+			},
+			{
+				Name: "Burn",
+				Fields: idl.Some[idl.IdlDefinedFields](idl.IdlDefinedFieldsNamed{
+					{Name: "quantity", Ty: &idltype.U32{}},
+				}),
+			},
+		},
+	}
+	return &idl.Idl{
+		Types: idl.IdTypeDef_slice{
+			{
+				Name: "MyAction",
+				Ty:   enumType,
+			},
+		},
+	}
+}
+
+func genComplexEnumSource(t *testing.T) string {
+	t.Helper()
+	idlData := complexEnumIDL()
+	gen := &Generator{
+		idl:     idlData,
+		options: &GeneratorOptions{Package: "test"},
+	}
+
+	enumType := idlData.Types[0].Ty.(*idl.IdlTypeDefTyEnum)
+	code, err := gen.gen_complexEnum("MyAction", nil, *enumType)
+	require.NoError(t, err)
+
+	f := jen.NewFile("test")
+	f.Add(code)
+	return f.GoString()
+}
+
+func TestComplexEnumEncode_nilInterfaceReturnsError(t *testing.T) {
+	src := genComplexEnumSource(t)
+
+	assert.Contains(t, src, "case nil:", "encoder must reject nil interface values")
+	assert.Contains(t, src, `cannot encode nil value`, "nil case must return a descriptive error")
+}
+
+func TestComplexEnumEncode_defaultArmReturnsError(t *testing.T) {
+	src := genComplexEnumSource(t)
+
+	assert.Contains(t, src, "default:", "encoder must reject unknown variant types")
+	assert.Contains(t, src, `unknown variant type`, "default case must return a descriptive error")
+}
+
+func TestComplexEnumEncode_nilPointerGuardPerVariant(t *testing.T) {
+	src := genComplexEnumSource(t)
+
+	assert.Contains(t, src, "realvalue == nil", "each variant case must guard against typed nil pointers")
+	assert.Contains(t, src, `cannot encode nil *MyAction_Transfer`,
+		"Transfer variant must have a nil-pointer error message")
+	assert.Contains(t, src, `cannot encode nil *MyAction_Burn`,
+		"Burn variant must have a nil-pointer error message")
+
+	nilGuards := strings.Count(src, "realvalue == nil")
+	assert.Equal(t, 2, nilGuards, "must have exactly one nil-pointer guard per variant")
+}
diff --git a/cmd/generate-bindings/solana/anchor-go/generator/types.go b/cmd/generate-bindings/solana/anchor-go/generator/types.go
index d3822fb1..04a267f2 100644
--- a/cmd/generate-bindings/solana/anchor-go/generator/types.go
+++ b/cmd/generate-bindings/solana/anchor-go/generator/types.go
@@ -226,17 +226,33 @@ func (g *Generator) gen_complexEnum(name string, docs []string, typ idl.IdlTypeD
 					argBody.List(Id("tmp")).Op(":=").Id(formatEnumContainerName(enumTypeName)).Block()
 					argBody.Switch(Id("realvalue").Op(":=").Id("value").Op(".").Parens(Type())).
 						BlockFunc(func(switchGroup *Group) {
-							// TODO: maybe it's from idl.Accounts ???
+							switchGroup.Case(Nil()).
+								BlockFunc(func(caseGroup *Group) {
+									caseGroup.Return(
+										Qual("fmt", "Errorf").Call(Lit(enumTypeName + ": cannot encode nil value")),
+									)
+								})
+
 							interfaceType := g.idl.Types.ByName(enumTypeName)
 							for variantIndex, variant := range interfaceType.Ty.(*idl.IdlTypeDefTyEnum).Variants {
 								variantTypeNameStruct := formatComplexEnumVariantTypeName(enumTypeName, variant.Name)
 
 								switchGroup.Case(Op("*").Id(variantTypeNameStruct)).
 									BlockFunc(func(caseGroup *Group) {
+										caseGroup.If(Id("realvalue").Op("==").Nil()).Block(
+											Return(Qual("fmt", "Errorf").Call(Lit(enumTypeName+": cannot encode nil *"+variantTypeNameStruct))),
+										)
 										caseGroup.Id("tmp").Dot("Enum").Op("=").Lit(variantIndex)
 										caseGroup.Id("tmp").Dot(tools.ToCamelUpper(variant.Name)).Op("=").Op("*").Id("realvalue")
 									})
 							}
+
+							switchGroup.Default().
+								BlockFunc(func(caseGroup *Group) {
+									caseGroup.Return(
+										Qual("fmt", "Errorf").Call(Lit(enumTypeName+": unknown variant type %T"), Id("value")),
+									)
+								})
 						})
 
 					argBody.Return(Id("encoder").Dot("Encode").Call(Id("tmp")))