What causes "no scope found for type '%s'" in vitessio/vitess?

Add the interface's package path to Options.Packages so it gets loaded into scopes

no scope found for type '%s'

Error message

no scope found for type '%s'

What it means

After splitting 'pkgname.TypeName', findTypeObject looks up pkgname in the loaded scopes map. If no loaded package has an import path matching pkgname, this error is returned, meaning the package containing the interface was not loaded or the path is misspelled.

Source

Thrown at go/tools/asthelpergen/asthelpergen.go:328

		return nil, err
	}

	return it, nil
}

// findTypeObject finds the types.Object for the given interface from the given scopes.
func findTypeObject(interfaceToFind string, scopes map[string]*types.Scope) (types.Object, error) {
	pos := strings.LastIndexByte(interfaceToFind, '.')
	if pos < 0 {
		return nil, fmt.Errorf("unexpected input type: %s", interfaceToFind)
	}

	pkgname := interfaceToFind[:pos]
	typename := interfaceToFind[pos+1:]

	scope := scopes[pkgname]
	if scope == nil {
		return nil, fmt.Errorf("no scope found for type '%s'", interfaceToFind)
	}

	tt := scope.Lookup(typename)
	if tt == nil {
		return nil, fmt.Errorf("no type called '%s' found in '%s'", typename, pkgname)
	}
	return tt, nil
}

var _ generatorSPI = (*astHelperGen)(nil)

func (gen *astHelperGen) scope() *types.Scope {
	return gen._scope
}

func (gen *astHelperGen) addType(t types.Type) {
	gen.todo = append(gen.todo, t)
}

View on GitHub (pinned to 01a25a7d17)

Solutions

Add the interface's package path to Options.Packages so it gets loaded into scopes
Verify the exact import path of the interface (go doc or IDE copy-reference)
Ensure findTypeObject keys and loaded package paths use identical path strings (no vendor/ prefix mismatch)

Example fix

// before
Packages: []string{"vitess.io/vitess/go/vt/sqlparser/ast"}
// after
Packages: []string{"vitess.io/vitess/go/vt/sqlparser"}

Defensive patterns

Strategy: validation

Validate before calling

pkg := "vitess.io/vitess/go/vt/sqlparser"
for _, iface := range options.Visitable {
    if strings.HasPrefix(iface, pkg+".") && !slices.Contains(options.Packages, pkg) {
        return fmt.Errorf("package %s must be in Options.Packages for %s", pkg, iface)
    }
}

Type guard

func pkgLoaded(scopes map[string]*types.Scope, iface string) bool {
    return scopes[iface[:strings.LastIndexByte(iface, '.')]] != nil
}

Prevention

Every interface listed for generation must belong to a package in Options.Packages
Update interface paths after any module/package reorganization
Add a unit test asserting all configured interfaces resolve in scopes

When it happens

Trigger: Options lists interface 'some/pkg/SQLNode' but options.Packages does not include 'some/pkg', so scopes lacks that key; or the package path is misspelled/outdated after a module reorganization.

Common situations: Adding an interface for generation but forgetting to add its package to Options.Packages; renamed import paths after a refactor.

Related errors

AI-assisted analysis of vitessio/vitess@01a25a7d17 (2026-09-01). Data as JSON: /api/errors/02a2e5b85bbbdd16. Report an issue: GitHub.