goxlsw panics when importing a project with a large number of empty sprite source files into a newly created project

[aofei]

all-sprites.gbp.zip

panic: runtime error: invalid memory address or nil pointer dereference
[signal 0xb code=0x0 addr=0x0 pc=0x0]
<empty string>
goroutine 8 [running]:
github.com/goplus/gop/ast.(*File).Pos(...)
	github.com/goplus/gop@v1.3.6/ast/ast_gop.go:488
github.com/goplus/goxlsw/internal/server.(*compileResult).fromPosition(0x1885200, 0x0, {{0x0, 0x0}, 0x0, 0x0, 0x0})
	github.com/goplus/goxlsw@v0.3.1/internal/server/compile.go:599 +0x3
github.com/goplus/goxlsw/internal/server.(*compileResult).rangeForASTFilePosition(...)
	github.com/goplus/goxlsw@v0.3.1/internal/server/compile.go:647
github.com/goplus/goxlsw/internal/server.(*compileResult).rangeForPos(0x1885200, 0x0)
	github.com/goplus/goxlsw@v0.3.1/internal/server/compile.go:653 +0xd
github.com/goplus/goxlsw/internal/server.(*Server).compileAt.func1({0x153100, 0x20d6080})
	github.com/goplus/goxlsw@v0.3.1/internal/server/compile.go:785 +0xa
github.com/goplus/goxlsw/internal/server.(*Server).compileAt(0x187f590, 0x1872210)
	github.com/goplus/goxlsw@v0.3.1/internal/server/compile.go:799 +0x80
github.com/goplus/goxlsw/internal/server.(*Server).compile(0x187f590)
	github.com/goplus/goxlsw@v0.3.1/internal/server/compile.go:703 +0x8
github.com/goplus/goxlsw/internal/server.(*Server).textDocumentDiagnostic(0x187f590, 0x187f5e0)
	github.com/goplus/goxlsw@v0.3.1/internal/server/diagnostic.go:5 +0x2
github.com/goplus/goxlsw/internal/server.(*Server).handleCall.func12()
	github.com/goplus/goxlsw@v0.3.1/internal/server/server.go:175 +0x2
github.com/goplus/goxlsw/internal/server.(*Server).handleCall.(*Server).runWithResponse.func30()
	github.com/goplus/goxlsw@v0.3.1/internal/server/server.go:297 +0x4
github.com/goplus/goxlsw/internal/server.(*Server).run.func1()
	github.com/goplus/goxlsw@v0.3.1/internal/server/server.go:288 +0x4
created by github.com/goplus/goxlsw/internal/server.(*Server).run in goroutine 7
	github.com/goplus/goxlsw@v0.3.1/internal/server/server.go:287 +0x5

[aofei]

This panic was triggered by a sprite named Game in the project mentioned in the OP, due to a bug in gop/gogen that generated a types.Error with an invalid Pos. (Related to #1085)