syntax: ABI-oblivious grammar#65884

Centril · 2019-10-28T03:31:28Z

This PR has the following effects:

extern $lit is now legal where $lit:literal and $lit is substituted for a string literal.
extern "abi_that_does_not_exist" is now syntactically legal whereas before, the set of ABI strings was hard-coded into the grammar of the language. With this PR, the set of ABIs are instead validated and translated during lowering. That seems more appropriate.
ast::FloatTy is now distinct from rustc_target::abi::FloatTy. The former is used substantially more and the translation between them is only necessary in a single place.
As a result of 2-3, libsyntax no longer depends on librustc_target, which should improve pipe-lining somewhat.

cc @rust-lang/lang -- the points 1-2 slightly change the definition of the language but in a way which seems consistent with our general principles (in particular wrt. the discussions of turning things into semantic errors). I expect this to be uncontroversial but it's worth letting y'all know. :)

r? @varkor

Centril · 2019-10-28T03:36:05Z

src/libsyntax/feature_gate/check.rs

(The purpose of doing this is so that if we add a new ABI but forget to feature gate it, an ICE will occur and it won't pass CI.)

petrochenkov · 2019-10-28T04:59:44Z

Assigning myself as well, I had some plans in this area.
cc #60493

src/libsyntax/parse/parser.rs

eddyb · 2019-10-28T06:15:05Z

I think @oli-obk moved FloatTy around, perhaps now we can have Primitive::{F32, F64} again instead of rustc_target::abi::FloatTy existing.

src/libsyntax/ast.rs

nikomatsakis · 2019-10-28T13:52:01Z

the points 1-2 slightly change the definition of the language but in a way which seems consistent with our general principles (in particular wrt. the discussions of turning things into semantic errors). I expect this to be uncontroversial but it's worth letting y'all know. :)

👍 from me

Centril · 2019-10-28T18:41:15Z

I think @oli-obk moved FloatTy around, perhaps now we can have Primitive::{F32, F64} again instead of rustc_target::abi::FloatTy existing.

@eddyb I don't have an opinion on this other than to say that it could be done in a follow-up. :)

eddyb · 2019-10-28T18:53:28Z

it could be done in a follow-up. :)

My argument would be that it's confusing to have two copies of the same type.
But I was also hoping for @oli-obk's opinion on this.

src/libsyntax/ast.rs

petrochenkov · 2019-10-28T19:47:08Z

src/libsyntax_pos/symbol.rs

src/libsyntax/parse/parser.rs

petrochenkov · 2019-10-29T20:07:36Z

r=me after addressing the remaining comments, unless varkor wants to review as well.

Centril · 2019-11-06T10:07:53Z

@bors r=petrochenkov

bors · 2019-11-06T10:07:54Z

📌 Commit 09979759ba46574d39d8ab0c4dc14566b918e949 has been approved by petrochenkov

We also sever syntax's dependency on rustc_target as a result. This should slightly improve pipe-lining. Moreover, some cleanup is done in related code.

Centril · 2019-11-07T04:27:22Z

@bors r=petrochenkov

bors · 2019-11-07T04:27:23Z

📌 Commit 55f76cd has been approved by petrochenkov

@varkor

…chenkov syntax: ABI-oblivious grammar This PR has the following effects: 1. `extern $lit` is now legal where `$lit:literal` and `$lit` is substituted for a string literal. 2. `extern "abi_that_does_not_exist"` is now *syntactically* legal whereas before, the set of ABI strings was hard-coded into the grammar of the language. With this PR, the set of ABIs are instead validated and translated during lowering. That seems more appropriate. 3. `ast::FloatTy` is now distinct from `rustc_target::abi::FloatTy`. The former is used substantially more and the translation between them is only necessary in a single place. 4. As a result of 2-3, libsyntax no longer depends on librustc_target, which should improve pipe-lining somewhat. cc @rust-lang/lang -- the points 1-2 slightly change the definition of the language but in a way which seems consistent with our general principles (in particular wrt. the discussions of turning things into semantic errors). I expect this to be uncontroversial but it's worth letting y'all know. :) r? @varkor

@ghost

Rollup of 5 pull requests Successful merges: - #59789 (Revert two unapproved changes to rustc_typeck.) - #65752 (Use structured suggestions for missing associated items) - #65884 (syntax: ABI-oblivious grammar) - #65974 (A scheme for more macro-matcher friendly pre-expansion gating) - #66017 (Add future incompatibility lint for `array.into_iter()`) Failed merges: - #66056 (rustc_metadata: Some reorganization of the module structure) r? @ghost

@oli-obk

rustc_target: inline abi::FloatTy into abi::Primitive. This effectively undoes a small part of @oli-obk's rust-lang#50967, now that the rest of the compiler doesn't use the `FloatTy` definition from `rustc_target`, post-rust-lang#65884.

Centril added T-lang Relevant to the language team relnotes Marks issues that should be documented in the release notes of the next release. labels Oct 28, 2019

Centril added this to the 1.40 milestone Oct 28, 2019

rust-highfive assigned varkor Oct 28, 2019