Diagnostics are different from those produced by calling tsc directly

[wincent]

In this project I see some puzzling differences between the diagnostics reported by:

• javascript-typescript-langserver (2.11.3) + LanguageClient-neovim (56859896904347856) + Neovim (v0.4.0-dev) + typescript (3.5.3)
• and tsc (from typescript 3.5.3)

tsc will report a clean build, but javascript-typescript-langserver complains in this file that Argument of type 'Iterable<T> | null | undefined' is not assignable to parameter of type 'ReadonlyArray<T> | null....

There are two SetConstructor overloads:

• https://github.com/microsoft/TypeScript/blob/70b7bd5a1b8c3bc1ba7c644b37412368607706e6/src/lib/es2015.iterable.d.ts#L188
• https://github.com/microsoft/TypeScript/blob/70b7bd5a1b8c3bc1ba7c644b37412368607706e6/src/lib/es2015.collection.d.ts#L48

Evidently, tsc alone is picking the former, but in the context of javascript-typescript-langserver, it's picking the latter, leading to the diagnostic.

If I turn debug logging on in LanguageClient-neovim, I get this.

And logging with --trace --logfil some-file to javascript-typescript-stdio I get this.

I don't know if this is related to #618 — perhaps it is not picking up my tsconfig.json. But I don't know if this is a bug in my own code, in TypeScript, in javascript-typescript-langserver, in LanguageClient-neovim, or maybe something else I am overlooking. One thing I did notice was that when I tried to repro in VSCode, it had the same problem, but when I updated it, the problem resolved; the release notes said:

JavaScript and TypeScript nightly extension

The new JavaScript and TypeScript nightly extension uses the nightly build of TypeScript (typescript@next) for VS Code's built-in TypeScript version, which powers JavaScript and TypeScript IntelliSense. This makes it easy to test the latest TypeScript features and provide feedback about them!"

[wincent]

When I directly interact with tsserver it agrees with tsc that there are no errors:

$ tsserver
Content-Length: 76

{"seq":0,"type":"event","event":"typingsInstallerPid","body":{"pid":91220}}
{"seq":1,"type":"quickinfo","command":"open","arguments":{"file":"/Users/glh/code/corpus/src/renderer/util/FrozenSet.ts"}}
Content-Length: 231

{"seq":0,"type":"event","event":"projectLoadingStart","body":{"projectName":"/Users/glh/code/corpus/tsconfig.json","reason":"Creating possible configured project for /Users/glh/code/corpus/src/renderer/util/FrozenSet.ts to open"}}
Content-Length: 118

{"seq":0,"type":"event","event":"projectLoadingFinish","body":{"projectName":"/Users/glh/code/corpus/tsconfig.json"}}
Content-Length: 717

{"seq":0,"type":"event","event":"telemetry","body":{"telemetryEventName":"projectInfo","payload":{"projectId":"689c12ab1bb1c95839aea14bce157cb3832179faeccd444e614b260d104bf81f","fileStats":{"js":0,"jsSize":0,"jsx":0,"jsxSize":0,"ts":5,"tsSize":7088,"tsx":12,"tsxSize":12539,"dts":99,"dtsSize":3906414,"deferred":0,"deferredSize":0},"compilerOptions":{"jsx":"react","module":"commonjs","moduleResolution":"node","outDir":"","strict":true,"target":"es2017"},"typeAcquisition":{"enable":false,"include":false,"exclude":false},"extends":false,"files":false,"include":true,"exclude":false,"compileOnSave":false,"configFileName":"tsconfig.json","projectType":"configured","languageServiceEnabled":true,"version":"3.5.3"}}}
Content-Length: 198

{"seq":0,"type":"event","event":"configFileDiag","body":{"triggerFile":"/Users/glh/code/corpus/src/renderer/util/FrozenSet.ts","configFile":"/Users/glh/code/corpus/tsconfig.json","diagnostics":[]}}
{"seq":2,"type":"request","command":"semanticDiagnosticsSync","arguments":{"file":"/Users/glh/code/corpus/src/renderer/util/FrozenSet.ts"}}
Content-Length: 105

{"seq":0,"type":"response","command":"semanticDiagnosticsSync","request_seq":2,"success":true,"body":[]}
^C
zsh: interrupt  tsserver

But looking at the process hierarchy, I see that javascript-typescript-stdio isn't actually interacting with tsserver in any obvious way, but by some other mechanism...

-+= 00001 root /sbin/launchd
 \-+= 70559 glh tmux new-session -d -s dot -n vim -x 179 -y 52
   \-+= 87237 glh -zsh
     \-+= 87678 glh zsh
       \-+= 90449 glh nvim src/renderer/util/FrozenSet.ts
         |-+= 90451 glh /Users/glh/code/wincent/roles/dotfiles/files/.vim/pack/bundle/opt/LanguageClient-neovim/bin/languageclient
         | \--- 90452 glh node /Users/glh/n/bin/javascript-typescript-stdio
         \--= 90454 glh /usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/Resources/Python.app/Contents/MacOS/Python -c import sys; sys.path.remove(""); import neovim; neovim.start_host() /Users/glh/code/wincent/roles/dotfiles/files/.vim/pack/bundle/opt/deoplete/rplugin/python3/deoplete

[wincent]

One final data point. If I swap out javascript-typescript-langserver for https://www.npmjs.com/package/typescript-language-server, then diagnostics agree with tsc/tsserver, as you'd expect, because I see it is using tsserver:

-+= 00001 root /sbin/launchd
 \-+= 70559 glh tmux new-session -d -s dot -n vim -x 179 -y 52
   \-+= 87237 glh -zsh
     \-+= 87678 glh zsh
       \-+= 91686 glh nvim src/renderer/util/FrozenSet.ts
         |-+= 91688 glh /Users/glh/code/wincent/roles/dotfiles/files/.vim/pack/bundle/opt/LanguageClient-neovim/bin/languageclient
         | \-+- 91689 glh node /Users/glh/n/bin/typescript-language-server --stdio
         |   \-+- 91691 glh node /Users/glh/code/corpus/node_modules/.bin/tsserver --cancellationPipeName /private/var/folders/tl/04jnvr4s34v704k5h2rqjmkh0000gn/T/7a8e12d526fe037a004e10233a71becc/tscancellation*
         |     \--- 91692 glh /Users/glh/n/bin/node /Users/glh/code/corpus/node_modules/typescript/lib/typingsInstaller.js --globalTypingsCacheLocation /Users/glh/Library/Caches/typescript/3.5 --typesMapLocation /Users/glh/code/corpus/node_modules/typescript/lib/typesMap.json
         |--= 91694 glh /usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/Resources/Python.app/Contents/MacOS/Python -c import sys; sys.path.remove(""); import neovim; neovim.start_host() script_host.py
         \--= 91698 glh /usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/Resources/Python.app/Contents/MacOS/Python -c import sys; sys.path.remove(""); import neovim; neovim.start_host() /Users/glh/code/wincent/roles/dotfiles/files/.vim/pack/bundle/opt/deoplete/rplugin/python3/deoplete