rust/tests/ui/proc-macro/meta-macro.rs

//@ aux-build:make-macro.rs
//@ aux-build:meta-macro.rs
//@ edition:2018
//@ compile-flags: -Z span-debug
//@ run-pass

#![no_std] // Don't load unnecessary hygiene information from std
extern crate std;

extern crate meta_macro;

fn main() {
    meta_macro::print_def_site!();
}
Serialize all foreign `SourceFile`s into proc-macro crate metadata Normally, we encode a `Span` that references a foreign `SourceFile` by encoding information about the foreign crate. When we decode this `Span`, we lookup the foreign crate in order to decode the `SourceFile`. However, this approach does not work for proc-macro crates. When we load a proc-macro crate, we do not deserialzie any of its dependencies (since a proc-macro crate can only export proc-macros). This means that we cannot serialize a reference to an upstream crate, since the associated metadata will not be available when we try to deserialize it. This commit modifies foreign span handling so that we treat all foreign `SourceFile`s as local `SourceFile`s when serializing a proc-macro. All `SourceFile`s will be stored into the metadata of a proc-macro crate, allowing us to cotinue to deserialize a proc-macro crate without needing to load any of its dependencies. Since the number of foreign `SourceFile`s that we load during a compilation session may be very large, we only serialize a `SourceFile` if we have also serialized a `Span` which requires it. 2020-06-24 12:16:36 -05:00			`//@ aux-build:make-macro.rs`
			`//@ aux-build:meta-macro.rs`
			`//@ edition:2018`
			`//@ compile-flags: -Z span-debug`
			`//@ run-pass`

Remove normalization of `Span` debug output in proc-macro tests Fixes #74800 The definition of `is_x86_feature_detected!` (and similar macros) depends on the platform - it is produced by a `cfg_if!` invocation on x86, and a plain `#[cfg]` on other platforms. Since it is part of the prelude, we will end up importing different hygiene information depending on the platform. This previously required us to avoid printing raw `SyntaxContext` ids in any tests that uses the standard library, since the captured output will be platform-dependent. Previously, we replaced all `SyntaxContext` ids with "#CTXT", and the raw `Span` lo/hi bytes with "LO..HI". This commit adds `#![no_std]` and `extern crate std` to all proc-macro tests that print spans. This suppresses the prelude import, while still using lang items from `std` (which gives us a buildable binary). With this apporach, we will only load hygiene information for things which we explicitly import. This lets us re-add `-Z unpretty=expanded,hygiene`, since its output can now be made stable across all platforms. Additionally, we use `-Z span-debug` in more places, which lets us avoid the "LO..HI" normalization hack. 2020-08-09 12:36:31 -05:00			`#![no_std] // Don't load unnecessary hygiene information from std`
			`extern crate std;`

Serialize all foreign `SourceFile`s into proc-macro crate metadata Normally, we encode a `Span` that references a foreign `SourceFile` by encoding information about the foreign crate. When we decode this `Span`, we lookup the foreign crate in order to decode the `SourceFile`. However, this approach does not work for proc-macro crates. When we load a proc-macro crate, we do not deserialzie any of its dependencies (since a proc-macro crate can only export proc-macros). This means that we cannot serialize a reference to an upstream crate, since the associated metadata will not be available when we try to deserialize it. This commit modifies foreign span handling so that we treat all foreign `SourceFile`s as local `SourceFile`s when serializing a proc-macro. All `SourceFile`s will be stored into the metadata of a proc-macro crate, allowing us to cotinue to deserialize a proc-macro crate without needing to load any of its dependencies. Since the number of foreign `SourceFile`s that we load during a compilation session may be very large, we only serialize a `SourceFile` if we have also serialized a `Span` which requires it. 2020-06-24 12:16:36 -05:00			`extern crate meta_macro;`

			`fn main() {`
			`meta_macro::print_def_site!();`
			`}`