}

func (sr *sparseFileReader) Read(b []byte) (n int, err error) {
	finished := int64(len(b)) >= sr.logicalRemaining()
	if finished {
		b = b[:sr.logicalRemaining()]
	}

	b0 := b
	endPos := sr.pos + int64(len(b))
	for endPos > sr.pos && err == nil {
		var nf int // Bytes read in fragment
		holeStart, holeEnd := sr.sp[0].Offset, sr.sp[0].endOffset()
		if sr.pos < holeStart { // In a data fragment

		children = append(children,
			tok(n.NamePos, len(n.Name)))

	case *ast.IfStmt:
		children = append(children,
			tok(n.If, len("if")))

	case *ast.ImportSpec:
		// TODO(adonovan): ImportSpec.{Doc,EndPos}?

	case *ast.IncDecStmt:
		children = append(children,
			tok(n.TokPos, len(n.Tok.String())))

	case *ast.IndexExpr:
		children = append(children,
			tok(n.Lbrack, len("[")),

			} else {
				first = c
			}
		}
	}
}

func (check *Checker) openScope(node syntax.Node, comment string) {
	check.openScopeUntil(node, syntax.EndPos(node), comment)
}

func (check *Checker) openScopeUntil(node syntax.Node, end syntax.Pos, comment string) {
	scope := NewScope(check.scope, node.Pos(), end, comment)
	check.recordScope(node, scope)

	// a function begins at the end of the ConstSpec or VarSpec (ShortVarDecl
	// for short variable declarations) and ends at the end of the innermost
	// containing block."
	scopePos := endPos(rhs[len(rhs)-1])
	for _, obj := range newVars {
		check.declare(scope, nil, obj, scopePos) // id = nil: recordDef already called
	}

	// a function begins at the end of the ConstSpec or VarSpec (ShortVarDecl
	// for short variable declarations) and ends at the end of the innermost
	// containing block."
	scopePos := endPos(rhs[len(rhs)-1])
	for _, obj := range newVars {
		check.declare(scope, nil, obj, scopePos) // id = nil: recordDef already called
	}

		// The package identifier denotes the current package,
		// but there is no corresponding package object.
		check.recordDef(file.PkgName, nil)

		fileScope := NewScope(pkg.scope, syntax.StartPos(file), syntax.EndPos(file), check.filename(fileNo))
		fileScopes = append(fileScopes, fileScope)
		check.recordScope(file, fileScope)

		// determine file directory, necessary to resolve imports