Running tsc manually crashes with "Parameter symbol already has a cached type which differs from newly assigned type"

[sirbrillig]

Quick summary

You can manually run the TypeScript type checks for the client directory with the command yarn tsc -p client --noEmit. This is helpful for finding TS errors before making a commit.

However, now when I run that command, I get the following unhelpful error:

/Users/payton/Code/wp-calypso/node_modules/typescript/lib/tsc.js:96888
                throw e;
                ^

Error: Debug Failure. Expected [object Object] === [object Object]. Parameter symbol already has a cached type which differs from newly assigned type
    at assignParameterType (/Users/payton/Code/wp-calypso/node_modules/typescript/lib/tsc.js:64862:26)
    at assignContextualParameterTypes (/Users/payton/Code/wp-calypso/node_modules/typescript/lib/tsc.js:64827:21)
    at contextuallyCheckFunctionExpressionOrObjectLiteralMethod (/Users/payton/Code/wp-calypso/node_modules/typescript/lib/tsc.js:65229:29)
    at checkFunctionExpressionOrObjectLiteralMethod (/Users/payton/Code/wp-calypso/node_modules/typescript/lib/tsc.js:65208:13)
    at checkExpressionWorker (/Users/payton/Code/wp-calypso/node_modules/typescript/lib/tsc.js:66805:28)
    at checkExpression (/Users/payton/Code/wp-calypso/node_modules/typescript/lib/tsc.js:66707:38)
    at checkExpressionWithContextualType (/Users/payton/Code/wp-calypso/node_modules/typescript/lib/tsc.js:66396:28)
    at inferTypeArguments (/Users/payton/Code/wp-calypso/node_modules/typescript/lib/tsc.js:62906:39)
    at chooseOverload (/Users/payton/Code/wp-calypso/node_modules/typescript/lib/tsc.js:63566:53)
    at resolveCall (/Users/payton/Code/wp-calypso/node_modules/typescript/lib/tsc.js:63403:26)

This same error happens if I run yarn tsc --build client/tsconfig.json which appears to run fine in the CI environment. I tried starting with a fresh node_modules and removing .tsc-cache but neither has any effect.

It seems to have been introduced by #66817. Before that commit, running the command works as expected. Afterward, it produces the error above.

However, I can't see how that PR could have caused any problems. I tried manually undoing the changes it made and the error continues.

Steps to reproduce

1. git checkout f0d3672658 (this is the merge commit which matches up to DSP Widget: add hook to test if enabled #66817)
2. yarn tsc -p client --noEmit
3. Notice that it displays a debug error.
4. git checkout f0d3672658~1 (this is the commit before DSP Widget: add hook to test if enabled #66817)
5. yarn tsc -p client --noEmit
6. Notice that the process completes successfully.

What you expected to happen

tsc should run and display any TypeScript errors.

What actually happened

tsc fails.

[sirbrillig]

🤔 Hang on...

I ran tsc inside the client directory, which does appear to work.

cd client && tsc

... and now running yarn tsc -p client --noEmit from the top-level directory seems to work again 🙃

Ok. Nevermind, I guess?

[noahtallen]

Super weird! Maybe a random bug with how yarn resolves binaries?

[sirbrillig]

🤷 Well, hopefully if anyone else encounters this, they'll find my "solution" helpful.

[sirbrillig]

Reopening this because it really happens a lot. I'd love to find a real solution.

[danielbachhuber]

This issue happens to me every time I miss a TypeScript error.

For example, the following diff produces a crash:

diff --git a/client/my-sites/hosting/sftp-card/ssh-keys.tsx b/client/my-sites/hosting/sftp-card/ssh-keys.tsx
index 7298936fa7..512416acab 100644
--- a/client/my-sites/hosting/sftp-card/ssh-keys.tsx
+++ b/client/my-sites/hosting/sftp-card/ssh-keys.tsx
@@ -18,7 +18,7 @@ import { useAttachSshKeyMutation } from './use-attach-ssh-key';
 import './ssh-keys.scss';
 
 interface SshKeysProps {
-	siteId: number;
+	sited: number;
 	siteSlug: string;
 	username: string;
 	disabled: boolean;

Maybe this is a known issue though? microsoft/TypeScript#50773

@Automattic/team-calypso-frameworks Is TypeScript supposed to crash this hard when there's an error? I would've expected more friendly error output...

[tyxla]

I hit this same error when trying to run yarn tsc --noEmit --project client/tsconfig.json so there must be something going on. I'm investigating.

[tyxla]

Got a fix for this #73991 that resolved it for me locally
Working on a fix, this still needs some work.
Finished the fix for this #73991 that resolved it for me locally - cc @danielbachhuber and @sirbrillig.