Allow `use` macro imports to shadow global macros #40501

jseyfried · 2017-03-14T02:42:04Z

Terminology:

global scope: builtin macros, macros from the prelude, #[macro_use], or #![plugin(..)].
legacy scope: crate-local macro_rules!.
modern scope: use macro imports, macro (once implemented).

Today, the legacy scope can shadow the global scope (modulo RFC 1560 expanded shadowing restrictions). However, the modern scope cannot shadow or be shadowed by either the global or legacy scopes, leading to ambiguity errors.

This PR allows the modern scope to shadow the global scope (subject to some restrictions).
More specifically, a name in the global scope is as shadowable as a glob import in the module self. In other words, we imagine a special, implicit glob import in each module item:

mod foo {
    #[lexical_only] // Not accessible via `foo::<name>`, like pre-RFC 1560 `use` imports.
    #[shadowable_by_legacy_scope] // for back-compat
    use <global_macros>::*;
}

r? @nrc

jseyfried · 2017-03-14T02:43:45Z

cc #35896
cc @keeperofdakeys @abonander

nrc · 2017-03-15T23:19:02Z

I think the terminology could be improved - built-in suggests that it is part of the compiler, but only a small subset of macros are and they are (iirc) in the prelude too. If I understand correctly, the distinction is more between legacy-imported and legacy-local?

nrc · 2017-03-15T23:43:51Z

LGTM, I'd like to fix (or better understand) the naming issue, but r+ with that.

jseyfried · 2017-03-16T03:18:15Z

Agreed -- I renamed "builtin scope" to "global scope".
@bors r=nrc

bors · 2017-03-16T03:18:16Z

📌 Commit a0707df has been approved by nrc

Rollup of 22 pull requests - Successful merges: #40241, #40346, #40348, #40377, #40398, #40409, #40441, #40445, #40509, #40521, #40523, #40532, #40538, #40564, #40581, #40583, #40588, #40589, #40590, #40603, #40611, #40621 - Failed merges: #40501, #40541

bors · 2017-03-19T13:58:12Z

☔ The latest upstream changes (presumably #40346) made this pull request unmergeable. Please resolve the merge conflicts.

jseyfried · 2017-03-24T00:15:26Z

@bors r=nrc

bors · 2017-03-24T00:15:27Z

📌 Commit d123e76 has been approved by nrc

@nrc

Allow `use` macro imports to shadow global macros Terminology: - global scope: builtin macros, macros from the prelude, `#[macro_use]`, or `#![plugin(..)]`. - legacy scope: crate-local `macro_rules!`. - modern scope: `use` macro imports, `macro` (once implemented). Today, the legacy scope can shadow the global scope (modulo RFC 1560 expanded shadowing restrictions). However, the modern scope cannot shadow or be shadowed by either the global or legacy scopes, leading to ambiguity errors. This PR allows the modern scope to shadow the global scope (subject to some restrictions). More specifically, a name in the global scope is as shadowable as a glob import in the module `self`. In other words, we imagine a special, implicit glob import in each module item: ```rust mod foo { #[lexical_only] // Not accessible via `foo::<name>`, like pre-RFC 1560 `use` imports. #[shadowable_by_legacy_scope] // for back-compat use <global_macros>::*; } ``` r? @nrc

Rollup of 5 pull requests - Successful merges: #40501, #40524, #40636, #40739, #40756 - Failed merges:

bors · 2017-03-24T14:10:13Z

🔒 Merge conflict

…n macros.

jseyfried · 2017-03-24T21:06:24Z

@bors r=nrc

bors · 2017-03-24T21:06:25Z

📌 Commit d64d381 has been approved by nrc

@nrc

Allow `use` macro imports to shadow global macros Terminology: - global scope: builtin macros, macros from the prelude, `#[macro_use]`, or `#![plugin(..)]`. - legacy scope: crate-local `macro_rules!`. - modern scope: `use` macro imports, `macro` (once implemented). Today, the legacy scope can shadow the global scope (modulo RFC 1560 expanded shadowing restrictions). However, the modern scope cannot shadow or be shadowed by either the global or legacy scopes, leading to ambiguity errors. This PR allows the modern scope to shadow the global scope (subject to some restrictions). More specifically, a name in the global scope is as shadowable as a glob import in the module `self`. In other words, we imagine a special, implicit glob import in each module item: ```rust mod foo { #[lexical_only] // Not accessible via `foo::<name>`, like pre-RFC 1560 `use` imports. #[shadowable_by_legacy_scope] // for back-compat use <global_macros>::*; } ``` r? @nrc

Rollup of 11 pull requests - Successful merges: #40347, #40501, #40516, #40524, #40540, #40642, #40683, #40764, #40778, #40807, #40809 - Failed merges: #40771

bors · 2017-03-25T11:24:23Z

⌛ Testing commit d64d381 with merge 7022e44...

bors · 2017-03-25T11:30:09Z

💔 Test failed - status-travis

arielb1 · 2017-03-25T12:30:01Z

try to fix the build on emscripten #40821
@bors retry

bors · 2017-03-25T13:44:14Z

⌛ Testing commit d64d381 with merge 1a95c82...

bors · 2017-03-25T13:48:08Z

💔 Test failed - status-travis

arielb1 · 2017-03-25T14:39:19Z

try to fix the build on emscripten #40821
@bors retry

bors · 2017-03-25T15:56:15Z

⌛ Testing commit d64d381 with merge 20ae752...

bors · 2017-03-25T16:02:08Z

💔 Test failed - status-travis

arielb1 · 2017-03-25T19:36:30Z

try to fix the build on emscripten #40821
@bors retry

bors · 2017-03-26T08:10:02Z

⌛ Testing commit d64d381 with merge ae3186d...

arielb1 · 2017-03-26T10:44:30Z

Debuginfo tests spurious failures on MinGW #40835
@bors retry

bors · 2017-03-26T11:45:18Z

⌛ Testing commit d64d381 with merge bcfd5c4...

@nrc

Allow `use` macro imports to shadow global macros Terminology: - global scope: builtin macros, macros from the prelude, `#[macro_use]`, or `#![plugin(..)]`. - legacy scope: crate-local `macro_rules!`. - modern scope: `use` macro imports, `macro` (once implemented). Today, the legacy scope can shadow the global scope (modulo RFC 1560 expanded shadowing restrictions). However, the modern scope cannot shadow or be shadowed by either the global or legacy scopes, leading to ambiguity errors. This PR allows the modern scope to shadow the global scope (subject to some restrictions). More specifically, a name in the global scope is as shadowable as a glob import in the module `self`. In other words, we imagine a special, implicit glob import in each module item: ```rust mod foo { #[lexical_only] // Not accessible via `foo::<name>`, like pre-RFC 1560 `use` imports. #[shadowable_by_legacy_scope] // for back-compat use <global_macros>::*; } ``` r? @nrc

bors · 2017-03-26T14:04:21Z

☀️ Test successful - status-appveyor, status-travis
Approved by: nrc
Pushing bcfd5c4 to master...

rust-highfive assigned nrc Mar 14, 2017

jseyfried mentioned this pull request Mar 14, 2017

Tracking issue for "macro naming and modularisation" (RFC #1561) #35896

Closed

jseyfried changed the title ~~Allow use macro imports to shadow built macors~~ Allow use macro imports to shadow builtin macors Mar 14, 2017

jseyfried changed the title ~~Allow use macro imports to shadow builtin macors~~ Allow use macro imports to shadow builtin macros Mar 14, 2017

jseyfried force-pushed the shadow_builtin_macros branch from 82ce9da to a19fde7 Compare March 14, 2017 05:06

jseyfried changed the title ~~Allow use macro imports to shadow builtin macros~~ Allow use macro imports to shadow global macros Mar 16, 2017

arielb1 mentioned this pull request Mar 18, 2017

Rollup of 22 pull requests #40644

Closed

jseyfried force-pushed the shadow_builtin_macros branch from a0707df to d123e76 Compare March 20, 2017 00:16

frewsxcv mentioned this pull request Mar 24, 2017

Rollup of 5 pull requests #40785

Closed

bors added a commit that referenced this pull request Mar 24, 2017

Auto merge of #40785 - frewsxcv:rollup, r=frewsxcv

8789360

Rollup of 5 pull requests - Successful merges: #40501, #40524, #40636, #40739, #40756 - Failed merges:

jseyfried added 2 commits March 24, 2017 21:05

Allow declarative macros 2.0 and use macro imports to shadow builti…

64e9af4

…n macros.

Rename builtin => global.

d64d381

jseyfried force-pushed the shadow_builtin_macros branch from d123e76 to d64d381 Compare March 24, 2017 21:06

alexcrichton mentioned this pull request Mar 25, 2017

Rollup of 11 pull requests #40810

Closed

bors added a commit that referenced this pull request Mar 25, 2017

Auto merge of #40810 - alexcrichton:rollup, r=alexcrichton

40ae49a

Rollup of 11 pull requests - Successful merges: #40347, #40501, #40516, #40524, #40540, #40642, #40683, #40764, #40778, #40807, #40809 - Failed merges: #40771

bors added a commit that referenced this pull request Mar 25, 2017

Auto merge of #40810 - alexcrichton:rollup, r=alexcrichton

ed9108d

Rollup of 11 pull requests - Successful merges: #40347, #40501, #40516, #40524, #40540, #40642, #40683, #40764, #40778, #40807, #40809 - Failed merges: #40771

bors merged commit d64d381 into rust-lang:master Mar 26, 2017

jseyfried deleted the shadow_builtin_macros branch March 26, 2017 21:00

Allow use macro imports to shadow global macros #40501

Allow use macro imports to shadow global macros #40501

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Allow `use` macro imports to shadow global macros #40501

Allow `use` macro imports to shadow global macros #40501

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