Currently we support safe property (`a?.b`) and method (`a?.b()`) accesses, but we don't handle safe keyed reads (`a?.[0]`) which is inconsistent. These changes expand the compiler in order to support safe key read expressions as well.
PR Close#41911
TypeScript supports ECMAScript private identifiers. It can happen that
developers intend to access such members from within an expression.
This currently results in an unclear error from the lexer. e.g.
```
'Parser Error: Unexpected token # at column 1 in [{{#myField}}] in C:/test.ts@5:2
```
We could improve such errors by tokenizing private identifiers similar to
how the TypeScript scanner processes them. Later we can report better
errors in the expression parser or in the typecheck block. This commit
causes all private identifier tokens to be disallowed, so it never
reaches the type checker. This is done intentionally as private
identifiers should not be considered valid Angular syntax, especially
because private fields are not guaranteed to be accessible from within
a component/directive definition (e.g. there cases where a template
function is generated outside of the class; which results in private
members not being accessible; and this results in mixed/confusing
behavior).
Fixes#36003.
PR Close#42027
In the past, only the starting index of an expression Token has been
recorded, so a parser could demarkate the span of a token only by the
start locations of two tokens. This may lead to trailing whitespace
being included in the token span:
```html
{{ token1 + token2 }}
^^^^^^^^^ recorded span of `token1`
```
It's also not enough for a parser to determine the end of a token by
adding the length of the token value to the token's start location,
because lexed expression values may not exactly reflect the source code.
For example, `"d\\"e"` is lexed as a string token whose value is `d"e`.
Instead, this commit adds a `end` field to expression tokens. `end`
is one past the last index of the token source code. This will enable a
parser to determine the span of a token just by looking at that token.
This is a breaking change because the contructor interface of `Token`
has changed.
Part of #33477.
PR Close#33549
