golang/go · error

import path %q is reserved and cannot be used

Error message

import path %q is reserved and cannot be used

What it means

Returned by checkImportPath when the path is one of the compiler-reserved import paths ("go" or "type"). These prefixes are reserved because the linker uses magic symbol prefixes "go:" and "type:", and allowing them as import paths would collide with generated internal symbols.

Source

Thrown at src/cmd/compile/internal/noder/import.go:313

	copy(fingerprint[:], buf)
	base.Ctxt.AddImport(path, fingerprint)

	return nil
}

func checkImportPath(path string, allowSpace bool) error {
	if path == "" {
		return errors.New("import path is empty")
	}

	if strings.Contains(path, "\x00") {
		return errors.New("import path contains NUL")
	}

	for ri := range base.ReservedImports {
		if path == ri {
			return fmt.Errorf("import path %q is reserved and cannot be used", path)
		}
	}

	for _, r := range path {
		switch {
		case r == utf8.RuneError:
			return fmt.Errorf("import path contains invalid UTF-8 sequence: %q", path)
		case r < 0x20 || r == 0x7f:
			return fmt.Errorf("import path contains control character: %q", path)
		case r == '\\':
			return fmt.Errorf("import path contains backslash; use slash: %q", path)
		case !allowSpace && unicode.IsSpace(r):
			return fmt.Errorf("import path contains space character: %q", path)
		case strings.ContainsRune("!\"#$%&'()*,:;<=>?[]^`{|}", r):
			return fmt.Errorf("import path contains invalid character '%c': %q", r, path)
		}
	}

View on GitHub (pinned to b6b368adc5)

Solutions

1. Rename the package/import path so the final element is not "go" or "type" (e.g. goutils, typeutil).
2. If you genuinely need a short path, use a module subpath like example.com/go/internal/....
3. Re-run goimports to let it resolve to a non-reserved path.

Example fix

// before
 import "go"
// after
 import "example.com/myproj/goutils"

import "cmd/compile/internal/base"
if base.ReservedImports[path] {
    return fmt.Errorf("rename package; %q is reserved", path)
}

// isReservedImportPath reports whether path is one of the compiler-reserved paths.
func isReservedImportPath(path string) bool {
    return path == "go" || path == "type"
}

When it happens

Trigger: A Go source file imports "go" or "type"; the loop over base.ReservedImports matches and the error reports the offending path.

Common situations: Naming a local module/package "go" or "type" and importing it; auto-generated import insertion picking a colliding short path; refactoring a package into a path whose final element is reserved.

Related errors

• import path contains invalid UTF-8 sequence: %q
• import path contains control character: %q
• import path contains backslash; use slash: %q
• import path contains space character: %q
• import path contains invalid character '%c': %q

AI-assisted analysis of golang/go@b6b368adc5 (2026-08-12). Data as JSON: /api/errors/1e7b79435285f9fe. Report an issue: GitHub.