fix(ivy): repeat template guards to narrow types in event handlers #35193
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In Ivy's template type checker, event bindings are checked in a closure to allow for accurate type inference of the `$event` parameter. Because of the closure, any narrowing effects of template guards will no longer be in effect when checking the event binding, as TypeScript assumes that the guard outside of the closure may no longer be true once the closure is invoked. For more information on TypeScript's Control Flow Analysis, please refer to microsoft/TypeScript#9998. In Angular templates, it is known that an event binding can only be executed when the view it occurs in is currently rendered, hence the corresponding template guard is known to hold during the invocation of an event handler closure. As such, it is desirable that any narrowing effects from template guards are still in effect within the event handler closure. This commit tweaks the generated Type-Check Block (TCB) to repeat all template guards within an event handler closure. This achieves the narrowing effect of the guards even within the closure. Fixes angular#35073
JoostK
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type: bug/fix
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alxhub
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Feb 6, 2020
JoostK
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kara
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Feb 7, 2020
…35193) In Ivy's template type checker, event bindings are checked in a closure to allow for accurate type inference of the `$event` parameter. Because of the closure, any narrowing effects of template guards will no longer be in effect when checking the event binding, as TypeScript assumes that the guard outside of the closure may no longer be true once the closure is invoked. For more information on TypeScript's Control Flow Analysis, please refer to microsoft/TypeScript#9998. In Angular templates, it is known that an event binding can only be executed when the view it occurs in is currently rendered, hence the corresponding template guard is known to hold during the invocation of an event handler closure. As such, it is desirable that any narrowing effects from template guards are still in effect within the event handler closure. This commit tweaks the generated Type-Check Block (TCB) to repeat all template guards within an event handler closure. This achieves the narrowing effect of the guards even within the closure. Fixes #35073 PR Close #35193
sonukapoor
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Feb 13, 2020
…ngular#35193) In Ivy's template type checker, event bindings are checked in a closure to allow for accurate type inference of the `$event` parameter. Because of the closure, any narrowing effects of template guards will no longer be in effect when checking the event binding, as TypeScript assumes that the guard outside of the closure may no longer be true once the closure is invoked. For more information on TypeScript's Control Flow Analysis, please refer to microsoft/TypeScript#9998. In Angular templates, it is known that an event binding can only be executed when the view it occurs in is currently rendered, hence the corresponding template guard is known to hold during the invocation of an event handler closure. As such, it is desirable that any narrowing effects from template guards are still in effect within the event handler closure. This commit tweaks the generated Type-Check Block (TCB) to repeat all template guards within an event handler closure. This achieves the narrowing effect of the guards even within the closure. Fixes angular#35073 PR Close angular#35193
sonukapoor
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to sonukapoor/angular
that referenced
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Feb 17, 2020
…ngular#35193) In Ivy's template type checker, event bindings are checked in a closure to allow for accurate type inference of the `$event` parameter. Because of the closure, any narrowing effects of template guards will no longer be in effect when checking the event binding, as TypeScript assumes that the guard outside of the closure may no longer be true once the closure is invoked. For more information on TypeScript's Control Flow Analysis, please refer to microsoft/TypeScript#9998. In Angular templates, it is known that an event binding can only be executed when the view it occurs in is currently rendered, hence the corresponding template guard is known to hold during the invocation of an event handler closure. As such, it is desirable that any narrowing effects from template guards are still in effect within the event handler closure. This commit tweaks the generated Type-Check Block (TCB) to repeat all template guards within an event handler closure. This achieves the narrowing effect of the guards even within the closure. Fixes angular#35073 PR Close angular#35193
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In Ivy's template type checker, event bindings are checked in a closure
to allow for accurate type inference of the
$eventparameter. Becauseof the closure, any narrowing effects of template guards will no longer
be in effect when checking the event binding, as TypeScript assumes that
the guard outside of the closure may no longer be true once the closure
is invoked. For more information on TypeScript's Control Flow Analysis,
please refer to microsoft/TypeScript#9998.
In Angular templates, it is known that an event binding can only be
executed when the view it occurs in is currently rendered, hence the
corresponding template guard is known to hold during the invocation of
an event handler closure. As such, it is desirable that any narrowing
effects from template guards are still in effect within the event
handler closure.
This commit tweaks the generated Type-Check Block (TCB) to repeat all
template guards within an event handler closure. This achieves the
narrowing effect of the guards even within the closure.
Fixes #35073