The R3TargetBinder "binds" an Angular template AST, computing semantic
information regarding the template and making it accessible.
One of the binding passes previously had a bug, where for the following
template:
<div *ngIf="foo as foo"></div>
which desugars to:
<ng-template ngIf [ngIf]="foo" let-foo="ngIf">
<div></div>
</ng-template>
would have the `[ngIf]` binding processed twice - in both the scope which
contains the `<ng-template>` and the scope inside the template. The bug
arises because during the latter, `foo` is a variable defined by `let-foo`,
and so the R3TargetBinder would incorrectly learn that `foo` inside `[ngIf]`
maps to that variable.
This commit fixes the bug by only processing inputs, outputs, and
templateAttrs from `Template`s in the outer scope.
PR Close#30669
b61784948a