microsoft/typescript-go · error

failed to marshal type %d: %w

Error message

failed to marshal type %d: %w

What it means

Error "failed to marshal type %d: %w" thrown in microsoft/typescript-go.

Source

Thrown at internal/tracing/tracing.go:520

	t.mu.Lock()
	types := slices.Clone(t.types)
	t.mu.Unlock()

	if len(types) == 0 {
		return nil
	}

	var sb strings.Builder
	// Write opening bracket (no newline so type ID matches line number)
	sb.WriteString("[")

	recursionIdentityMap := make(map[any]int)

	for i, typ := range types {
		descriptor := t.buildTypeDescriptor(typ, recursionIdentityMap)

		if err := json.MarshalWrite(&sb, descriptor); err != nil {
			return fmt.Errorf("failed to marshal type %d: %w", typ.Id(), err)
		}

		if i < len(types)-1 {
			sb.WriteString(",\n")
		}
	}

	sb.WriteString("]\n")

	return t.fs.WriteFile(t.typesPath, sb.String())
}

// TypeDescriptor represents a type in the output JSON
type TypeDescriptor struct {
	ID                      uint32   `json:"id"`
	IntrinsicName           string   `json:"intrinsicName,omitzero"`
	SymbolName              string   `json:"symbolName,omitzero"`
	RecursionID             *int     `json:"recursionId,omitzero"`

View on GitHub (pinned to 1bcfa18d79)

When it happens

Trigger: Thrown at internal/tracing/tracing.go:520 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of microsoft/typescript-go@1bcfa18d79 (2026-08-16). Data as JSON: /api/errors/8a07a2164b335225. Report an issue: GitHub.