for s := b; s != nil; s = s.parent {
		if t := s.labels[name]; t != nil {
			return t
		}
	}
	return nil
}

// enclosingTarget returns the innermost enclosing labeled
// statement with the given label name, or nil.
func (b *block) enclosingTarget(name string) *syntax.LabeledStmt {
	for s := b; s != nil; s = s.parent {
		if t := s.lstmt; t != nil && t.Label.Value == name {
			return t
		}
	}

	for s := b; s != nil; s = s.parent {
		if t := s.labels[name]; t != nil {
			return t
		}
	}
	return nil
}

// enclosingTarget returns the innermost enclosing labeled
// statement with the given label name, or nil.
func (b *block) enclosingTarget(name string) *ast.LabeledStmt {
	for s := b; s != nil; s = s.parent {
		if t := s.lstmt; t != nil && t.Label.Name == name {
			return t
		}
	}

}

var invalid = new(LabeledStmt) // singleton to signal invalid enclosing target

// enclosingTarget returns the innermost enclosing labeled statement matching
// the given name. The result is nil if the label is not defined, and invalid
// if the label is defined but doesn't label a valid labeled statement.
func (ls *labelScope) enclosingTarget(b *block, name string) *LabeledStmt {
	if l := ls.labels[name]; l != nil {