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Sophia J. Turner (sophiajt)

opened on Aug 25, 2015

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We currently support extends null using #3516 and #3524, but I was wondering if we might also want to error on incorrectly using 'extends null'

class C extends null{
    x: number;
}

var c: C;
c.toString()

From the Mozilla docs "Extending from null works like with a normal class, except that the prototype object does not inherit from Object.prototype."

I may be missing something in the above example (apologies if so), but it looks like we might want to warn on the use of toString since, assuming I'm reading it correctly, this method does not exist on an instance of C.

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1. Sophia J. Turner (sophiajt)

   changed the title [-]'extends null' doesn't seem to error on using methods from Object.prototype[/-] [+]'extends null' doesn't error on using methods from Object.prototype[/+] on Aug 25, 2015
2. danquirk commented on Aug 25, 2015

   

   Dan Quirk (danquirk)

   on Aug 25, 2015

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   Probably some relevant discussion in #3696 and the linked issues therein
3. sophiajt commented on Aug 25, 2015

   

   Sophia J. Turner (sophiajt)

   on Aug 25, 2015

   ContributorAuthor

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   Good catch. Missed that one when I searched
4. mhegazy commented on Aug 26, 2015

   

   Mohamed Hegazy (mhegazy)

   on Aug 26, 2015

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   This is by design so far. We assume that Object is the super type of everything. if we want this to work, we need to change this assumption. the complexity of the change does not map to the value added to the user by enabling this feature.
5. Mohamed Hegazy (mhegazy)

   added

   By DesignDeprecated - use "Working as Intended" or "Design Limitation" insteadDeprecated - use "Working as Intended" or "Design Limitation" instead

   Won't FixThe severity and priority of this issue do not warrant the time or complexity needed to fix itThe severity and priority of this issue do not warrant the time or complexity needed to fix it

   BugA bug in TypeScriptA bug in TypeScript

   and removed

   By DesignDeprecated - use "Working as Intended" or "Design Limitation" insteadDeprecated - use "Working as Intended" or "Design Limitation" instead

   on Aug 26, 2015
6. Mohamed Hegazy (mhegazy)

   closed this as completedon Aug 26, 2015
7. microsoft

   locked and limited conversation to collaborators on Jun 19, 2018

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