Internal compiler crash with namespace and enum

[evanw]

Bug Report

🔎 Search Terms

namespace enum compiler crash computeEnumMemberValues TypeError undefined length

🕗 Version & Regression Information

• This is the behavior in every version I tried

⏯ Playground Link

Playground link with relevant code

💻 Code

namespace x { export let y = 123 }
enum x { z = y }

🙁 Actual behavior

$ tsc example.ts
./node_modules/typescript/lib/tsc.js:94427
                throw e;
                ^

TypeError: Cannot read properties of undefined (reading 'length')
    at computeEnumMemberValues (./node_modules/typescript/lib/tsc.js:68888:61)
    at getEnumMemberValue (./node_modules/typescript/lib/tsc.js:70894:13)
    at evaluateEnumMember (./node_modules/typescript/lib/tsc.js:69025:36)
    at evaluate (./node_modules/typescript/lib/tsc.js:68998:61)
    at computeConstantValue (./node_modules/typescript/lib/tsc.js:68922:86)
    at computeMemberValue (./node_modules/typescript/lib/tsc.js:68907:24)
    at computeEnumMemberValues (./node_modules/typescript/lib/tsc.js:68890:33)
    at checkEnumDeclaration (./node_modules/typescript/lib/tsc.js:69051:13)
    at checkSourceElementWorker (./node_modules/typescript/lib/tsc.js:69825:28)
    at checkSourceElement (./node_modules/typescript/lib/tsc.js:69657:17)
    at Object.forEach (./node_modules/typescript/lib/tsc.js:132:30)
    at checkSourceFileWorker (./node_modules/typescript/lib/tsc.js:69985:20)
    at checkSourceFile (./node_modules/typescript/lib/tsc.js:69953:13)
    at getDiagnosticsWorker (./node_modules/typescript/lib/tsc.js:70039:17)
    at Object.getDiagnostics (./node_modules/typescript/lib/tsc.js:70028:24)
    at ./node_modules/typescript/lib/tsc.js:94448:85
    at runWithCancellationToken (./node_modules/typescript/lib/tsc.js:94420:24)
    at getBindAndCheckDiagnosticsForFileNoCache (./node_modules/typescript/lib/tsc.js:94437:20)
    at getAndCacheDiagnostics (./node_modules/typescript/lib/tsc.js:94685:26)
    at getBindAndCheckDiagnosticsForFile (./node_modules/typescript/lib/tsc.js:94434:20)
    at getSemanticDiagnosticsForFile (./node_modules/typescript/lib/tsc.js:94431:61)
    at ./node_modules/typescript/lib/tsc.js:94371:24
    at Object.flatMap (./node_modules/typescript/lib/tsc.js:428:25)
    at getDiagnosticsHelper (./node_modules/typescript/lib/tsc.js:94367:56)
    at Object.getSemanticDiagnostics (./node_modules/typescript/lib/tsc.js:94378:20)
    at emitFilesAndReportErrors (./node_modules/typescript/lib/tsc.js:99038:57)
    at Object.emitFilesAndReportErrorsAndGetExitStatus (./node_modules/typescript/lib/tsc.js:99067:18)
    at performCompilation (./node_modules/typescript/lib/tsc.js:101947:29)
    at executeCommandLineWorker (./node_modules/typescript/lib/tsc.js:101849:17)
    at Object.executeCommandLine (./node_modules/typescript/lib/tsc.js:101876:20)
    at Object.<anonymous> (./node_modules/typescript/lib/tsc.js:102170:4)
    at Module._compile (node:internal/modules/cjs/loader:1101:14)
    at Object.Module._extensions..js (node:internal/modules/cjs/loader:1153:10)
    at Module.load (node:internal/modules/cjs/loader:981:32)
    at Function.Module._load (node:internal/modules/cjs/loader:822:12)
    at Module.require (node:internal/modules/cjs/loader:1005:19)
    at require (node:internal/modules/cjs/helpers:102:18)
    at Object.<anonymous> (./node_modules/typescript/bin/tsc:2:1)
    at Module._compile (node:internal/modules/cjs/loader:1101:14)
    at Object.Module._extensions..js (node:internal/modules/cjs/loader:1153:10)
    at Module.load (node:internal/modules/cjs/loader:981:32)
    at Function.Module._load (node:internal/modules/cjs/loader:822:12)
    at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:81:12)
    at node:internal/main/run_main_module:17:47

🙂 Expected behavior

I expected tsc to either generate code or report an error diagnostic, but not to hard-crash like this.

For context, I'm trying to reverse-engineer what the semantics of enum/namespace interactions are to help improve esbuild's enum/namespace support. Specifically I'm investigating the feasibility of solving evanw/esbuild#1410. I hit this crash as part of that investigation and I figured it'd be useful to report it.

[RyanCavanaugh]

Appreciate the excellent reports as usual 👍