This commit starts to add infrastructure for targeted diagnostics in the
`#[wasm_bindgen]` attribute, intended eventually at providing much better errors
as they'll be pointing to exactly the code in question rather than always to a
`#[wasm_bindgen]` attribute.
The general changes are are:
* A new `Diagnostic` error type is added to the backend. A `Diagnostic` is
created with a textual error or with a span, and it can also be created from a
list of diagnostics. A `Diagnostic` implements `ToTokens` which emits a bunch
of invocations of `compile_error!` that will cause rustc to later generate
errors.
* Fallible implementations of `ToTokens` have switched to using a new trait,
`TryToTokens`, which returns a `Result` to use `?` with.
* The `MacroParse` trait has changed to returning a `Result` to propagate errors
upwards.
* A new `ui-tests` crate was added which uses `compiletest_rs` to add UI tests.
These UI tests will verify that our output improves over time and does not
regress. This test suite is added to CI as a new builder as well.
* No `Diagnostic` instances are created just yet, everything continues to panic
and return `Ok`, with the one exception of the top-level invocations of
`syn::parse` which now create a `Diagnostic` and pass it along.
This commit does not immediately improve diagnostics but the intention is that
it is laying the groundwork for improving diagnostics over time. It should
ideally be much easier to contribute improved diagnostics after this commit!
cc #601
* Bump to 0.2.12
* Update all version numbers and deps
* Update all listed authors to `["The wasm-bindgen Developers"]`
* Update `repository` links to specific paths for each crate
* Update `homepage` links to the online book
* Update all links away from `alexcrichton/wasm-bindgen`
* Add `#[doc]` directives for HTML URLs
* Update more version requirements
* Fill out CHANGELOG
* remove BindgenAttrs from other backend::ast structs
This is primarily a tool for use with the macro crate. Most of
these attributes were ignored in the actual codegen, but a few
were still being used. This is confusing when trying to add
other sources for codegen (such as webidl and typescript).
* move parsing logic to macro crate
This makes the backend crate solely concerned with having an ast
for which we can generate code.
Using `proc-macro2`'s `nightly` feature is a good default for most use cases.
However, it causes a build error if used together with crates such as
`cssparser` that also use `proc-macro2` from a build script.
This change adds a default enabled feature `spans` that users can disable if
they need to work around this conflict.
Fixes#160.
