In a microsyntax expressions, some attributes are not bound after
desugaring. For example,
```html
<div *ngFor="let item of items">
</div>
```
gets desugared to
```html
<ng-template ngFor let-items [ngForOf]="items">
</ngtemplate>
```
In this case, `ngFor` should be a literal attribute with no RHS value.
Therefore, its source span should be just the `keySpan` and not the
source span of the original template node.
This allows language service to precisely pinpoint different spans in a
microsyntax to provide accurate information.
PR Close#38766
Previously, the `sourceSpan` and `startSourceSpan` were the same
object, which meant that you had the following situation:
```
element = <div>some content</div>
sourceSpan = <div>
startSourceSpan = <div>
endSourceSpan = </div>
```
This made `sourceSpan` redundant and meant that if you
wanted a span for the whole element including its content
and closing tag, it had to be computed.
Now `sourceSpan` is separated from `startSourceSpan`
resulting in:
```
element = <div>some content</div>
sourceSpan = <div>some content</div>
startSourceSpan = <div>
endSourceSpan = </div>
```
PR Close#38581
This commit propagates the correct value span in an ExpressionBinding of
a microsyntax expression to ParsedProperty, which in turn porpagates the
span to the template ASTs (both VE and Ivy).
PR Close#36133
This commit propagates the `sourceSpan` and `valueSpan` of a `VariableBinding`
in a microsyntax expression to `ParsedVariable`, and subsequently to
View Engine Variable AST and Ivy Variable AST.
Note that this commit does not propagate the `keySpan`, because it involves
significant changes to the template AST.
PR Close#36047
The only test case for `ngFor` exercises an incorrect usage which causes
two bound attributes to be generated . This commit adds a canonical and
correct usage to show the difference between the two.
PR Close#35671
Template AST nodes for (bound) attributes, variables and references will
now retain a reference to the source span of their value, which allows
for more accurate type check diagnostics.
PR Close#30181
Keen Yee Liau
Pete Bacon Darwin
Joey Perrott
Alex Rickabaugh
Keen Yee Liau
JoostK