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--allowJs: Cannot update prototype of imported class (3.7.0 regression) #34493
Description
TypeScript Version: 3.7.0-dev.20191015
Code
Initial source:
lodash-es/lodash.default.js file from lodash-es@4.17.15
Minimum repro:
import A from 'A';
A.prototype.foo = 0;
Expected behavior:
Code transpiles without errors
Actual behavior:
node_modules\typescript\lib\tsc.js:23676
node.symbol = symbol;
TypeError: node_modules\lodash-es\lodash.default.js: Cannot set property 'symbol' of undefined
at addDeclarationToSymbol (node_modules/typescript/lib/typescript.js:29235:25)
at bindPotentiallyMissingNamespaces (node_modules/typescript/lib/typescript.js:31604:17)
at bindPropertyAssignment (node_modules/typescript/lib/typescript.js:31656:31)
at bindPrototypePropertyAssignment (node_modules/typescript/lib/typescript.js:31544:13)
at bindWorker (node_modules/typescript/lib/typescript.js:31139:29)
at bind (node_modules/typescript/lib/typescript.js:31027:13)
at bindExpressionStatement (node_modules/typescript/lib/typescript.js:30235:13)
at bindChildrenWorker (node_modules/typescript/lib/typescript.js:29693:21)
at bindChildren (node_modules/typescript/lib/typescript.js:29614:17)
at bind (node_modules/typescript/lib/typescript.js:31038:21)
Playground Link:
http://www.typescriptlang.org/play/?target=1&ts=3.7-Beta&useJavaScript=true#code/JYWwDg9gTgLgBAQTgMyhEcDkDMG4BQCAdGGjBDAJ5gCmRyEEcAvHAAy5A (see error in browser console)
Activity
Knagis commentedon Oct 15, 2019
Minimum repro:
[-]Cannot set property 'symbol' of undefined: 3.7.0 cannot transpile lodash-es/lodash.defaults.js[/-][+]--allowJs: Cannot update prototype of imported class (3.7.0)[/+][-]--allowJs: Cannot update prototype of imported class (3.7.0)[/-][+]--allowJs: Cannot update prototype of imported class (3.7.0 regression)[/+]sandersn commentedon Oct 18, 2019
Ais an alias symbol, which doesn't get a valueDeclaration, but the expando binding assumes that the original symbol has a valueDeclaration.I'm not sure whether the right fix is to not skip expando binding when the original symbol doesn't have a valueDeclaration, or to rebind the alias' declaration as a valueDeclaration. I'll try both and see which behaves better.
sandersn commentedon Oct 18, 2019
Since the RC snaps at 2 PM today, I'm going to fix the crash (option 1 above) and investigate the follow-on crash from option 2 afterward. Option 2 should restore the pre-3.7 behaviour when it works.
sandersn commentedon Oct 18, 2019
My historical repro was set up wrong -- now that I've fixed it, I can see that this never worked, so I will probably leave it at fixing the crash.
Fix crash in expando assignment to alias
Fix crash in expando assignment to alias (#34566)