From d6a7c1d47fdf68626b5535ff24bd115e4aba7d71 Mon Sep 17 00:00:00 2001 From: Aaron Hill Date: Mon, 15 Mar 2021 15:54:25 -0400 Subject: [PATCH] Extend `proc_macro_back_compat` lint to `procedural-masquerade` We now lint on *any* use of `procedural-masquerade` crate. While this crate still exists, its main reverse dependency (`cssparser`) no longer depends on it. Any crates still depending off should stop doing so, as it only exists to support very old Rust versions. If a crate actually needs to support old versions of rustc via `procedural-masquerade`, then they'll just need to accept the warning until we remove it entirely (at the same time as the back-compat hack). The latest version of `procedural-masquerade` does not work with the latest rustc, but trying to check for the version seems like more trouble than it's worth. While working on this, I realized that the `proc-macro-hack` check was never actually doing anything. The corresponding enum variant in `proc-macro-hack` is named `Value` or `Nested` - it has never been called `Input`. Due to a strange Crater issue, the Crater run that tested adding this did *not* end up testing it - some of the crates that would have failed did not actually have their tests checked, making it seem as though the `proc-macro-hack` check was working. The Crater issue is being discussed at https://rust-lang.zulipchat.com/#narrow/stream/242791-t-infra/topic/Nearly.20identical.20Crater.20runs.20processed.20a.20crate.20differently/near/230406661 Despite the `proc-macro-hack` check not actually doing anything, we haven't gotten any reports from users about their build being broken. I went ahead and removed it entirely, since it's clear that no one is being affected by the `proc-macro-hack` regression in practice. --- compiler/rustc_ast/src/token.rs | 27 ------------- compiler/rustc_expand/src/base.rs | 40 +++++++++++++++++++ compiler/rustc_expand/src/proc_macro.rs | 3 +- .../rustc_expand/src/proc_macro_server.rs | 2 +- .../issue-73933-procedural-masquerade.rs | 13 ++++++ .../issue-73933-procedural-masquerade.stderr | 25 ++++++++++++ .../issue-73933-procedural-masquerade.stdout | 22 ++++++++++ 7 files changed, 103 insertions(+), 29 deletions(-) create mode 100644 src/test/ui/proc-macro/issue-73933-procedural-masquerade.rs create mode 100644 src/test/ui/proc-macro/issue-73933-procedural-masquerade.stderr create mode 100644 src/test/ui/proc-macro/issue-73933-procedural-masquerade.stdout diff --git a/compiler/rustc_ast/src/token.rs b/compiler/rustc_ast/src/token.rs index 093f7f2668c46..7e58426d27de4 100644 --- a/compiler/rustc_ast/src/token.rs +++ b/compiler/rustc_ast/src/token.rs @@ -784,33 +784,6 @@ impl Nonterminal { NtTT(tt) => tt.span(), } } - - /// This nonterminal looks like some specific enums from - /// `proc-macro-hack` and `procedural-masquerade` crates. - /// We need to maintain some special pretty-printing behavior for them due to incorrect - /// asserts in old versions of those crates and their wide use in the ecosystem. - /// See issue #73345 for more details. - /// FIXME(#73933): Remove this eventually. - pub fn pretty_printing_compatibility_hack(&self) -> bool { - let item = match self { - NtItem(item) => item, - NtStmt(stmt) => match &stmt.kind { - ast::StmtKind::Item(item) => item, - _ => return false, - }, - _ => return false, - }; - - let name = item.ident.name; - if name == sym::ProceduralMasqueradeDummyType || name == sym::ProcMacroHack { - if let ast::ItemKind::Enum(enum_def, _) = &item.kind { - if let [variant] = &*enum_def.variants { - return variant.ident.name == sym::Input; - } - } - } - false - } } impl PartialEq for Nonterminal { diff --git a/compiler/rustc_expand/src/base.rs b/compiler/rustc_expand/src/base.rs index dd93fe8350e42..ce65793051837 100644 --- a/compiler/rustc_expand/src/base.rs +++ b/compiler/rustc_expand/src/base.rs @@ -10,6 +10,8 @@ use rustc_attr::{self as attr, Deprecation, Stability}; use rustc_data_structures::fx::FxHashMap; use rustc_data_structures::sync::{self, Lrc}; use rustc_errors::{DiagnosticBuilder, ErrorReported}; +use rustc_lint_defs::builtin::PROC_MACRO_BACK_COMPAT; +use rustc_lint_defs::BuiltinLintDiagnostics; use rustc_parse::{self, nt_to_tokenstream, parser, MACRO_ARGUMENTS}; use rustc_session::{parse::ParseSess, Limit, Session}; use rustc_span::def_id::DefId; @@ -1241,3 +1243,41 @@ pub fn get_exprs_from_tts( } Some(es) } + +/// This nonterminal looks like some specific enums from +/// `proc-macro-hack` and `procedural-masquerade` crates. +/// We need to maintain some special pretty-printing behavior for them due to incorrect +/// asserts in old versions of those crates and their wide use in the ecosystem. +/// See issue #73345 for more details. +/// FIXME(#73933): Remove this eventually. +pub(crate) fn pretty_printing_compatibility_hack(nt: &Nonterminal, sess: &ParseSess) -> bool { + let item = match nt { + Nonterminal::NtItem(item) => item, + Nonterminal::NtStmt(stmt) => match &stmt.kind { + ast::StmtKind::Item(item) => item, + _ => return false, + }, + _ => return false, + }; + + let name = item.ident.name; + if name == sym::ProceduralMasqueradeDummyType { + if let ast::ItemKind::Enum(enum_def, _) = &item.kind { + if let [variant] = &*enum_def.variants { + if variant.ident.name == sym::Input { + sess.buffer_lint_with_diagnostic( + &PROC_MACRO_BACK_COMPAT, + item.ident.span, + ast::CRATE_NODE_ID, + "using `procedural-masquerade` crate", + BuiltinLintDiagnostics::ProcMacroBackCompat( + "The `procedural-masquerade` crate has been unnecessary since Rust 1.30.0. \ + Versions of this crate below 0.1.7 will eventually stop compiling.".to_string()) + ); + return true; + } + } + } + } + false +} diff --git a/compiler/rustc_expand/src/proc_macro.rs b/compiler/rustc_expand/src/proc_macro.rs index 8cbaa7c945a81..61b776ff2d280 100644 --- a/compiler/rustc_expand/src/proc_macro.rs +++ b/compiler/rustc_expand/src/proc_macro.rs @@ -90,7 +90,8 @@ impl MultiItemModifier for ProcMacroDerive { } _ => unreachable!(), }; - let input = if item.pretty_printing_compatibility_hack() { + let input = if crate::base::pretty_printing_compatibility_hack(&item, &ecx.sess.parse_sess) + { TokenTree::token(token::Interpolated(Lrc::new(item)), DUMMY_SP).into() } else { nt_to_tokenstream(&item, &ecx.sess.parse_sess, CanSynthesizeMissingTokens::Yes) diff --git a/compiler/rustc_expand/src/proc_macro_server.rs b/compiler/rustc_expand/src/proc_macro_server.rs index 837fad905800a..67edfe19da383 100644 --- a/compiler/rustc_expand/src/proc_macro_server.rs +++ b/compiler/rustc_expand/src/proc_macro_server.rs @@ -187,7 +187,7 @@ impl FromInternal<(TreeAndSpacing, &'_ ParseSess, &'_ mut Vec)> delimiter: Delimiter::None, stream, span: DelimSpan::from_single(span), - flatten: nt.pretty_printing_compatibility_hack(), + flatten: crate::base::pretty_printing_compatibility_hack(&nt, sess), }) } } diff --git a/src/test/ui/proc-macro/issue-73933-procedural-masquerade.rs b/src/test/ui/proc-macro/issue-73933-procedural-masquerade.rs new file mode 100644 index 0000000000000..abc3d2691a307 --- /dev/null +++ b/src/test/ui/proc-macro/issue-73933-procedural-masquerade.rs @@ -0,0 +1,13 @@ +// check-pass +// aux-build:test-macros.rs + +#[macro_use] +extern crate test_macros; + +#[derive(Print)] +enum ProceduralMasqueradeDummyType { //~ WARN using +//~| WARN this was previously + Input +} + +fn main() {} diff --git a/src/test/ui/proc-macro/issue-73933-procedural-masquerade.stderr b/src/test/ui/proc-macro/issue-73933-procedural-masquerade.stderr new file mode 100644 index 0000000000000..0b930705e3510 --- /dev/null +++ b/src/test/ui/proc-macro/issue-73933-procedural-masquerade.stderr @@ -0,0 +1,25 @@ +warning: using `procedural-masquerade` crate + --> $DIR/issue-73933-procedural-masquerade.rs:8:6 + | +LL | enum ProceduralMasqueradeDummyType { + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | + = note: `#[warn(proc_macro_back_compat)]` on by default + = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release! + = note: for more information, see issue #83125 + = note: The `procedural-masquerade` crate has been unnecessary since Rust 1.30.0. Versions of this crate below 0.1.7 will eventually stop compiling. + +warning: 1 warning emitted + +Future incompatibility report: Future breakage date: None, diagnostic: +warning: using `procedural-masquerade` crate + --> $DIR/issue-73933-procedural-masquerade.rs:8:6 + | +LL | enum ProceduralMasqueradeDummyType { + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | + = note: `#[warn(proc_macro_back_compat)]` on by default + = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release! + = note: for more information, see issue #83125 + = note: The `procedural-masquerade` crate has been unnecessary since Rust 1.30.0. Versions of this crate below 0.1.7 will eventually stop compiling. + diff --git a/src/test/ui/proc-macro/issue-73933-procedural-masquerade.stdout b/src/test/ui/proc-macro/issue-73933-procedural-masquerade.stdout new file mode 100644 index 0000000000000..8edd68f8a3b84 --- /dev/null +++ b/src/test/ui/proc-macro/issue-73933-procedural-masquerade.stdout @@ -0,0 +1,22 @@ +PRINT-DERIVE INPUT (DISPLAY): enum ProceduralMasqueradeDummyType { Input, } +PRINT-DERIVE RE-COLLECTED (DISPLAY): enum ProceduralMasqueradeDummyType { Input } +PRINT-DERIVE INPUT (DEBUG): TokenStream [ + Ident { + ident: "enum", + span: #0 bytes(100..104), + }, + Ident { + ident: "ProceduralMasqueradeDummyType", + span: #0 bytes(105..134), + }, + Group { + delimiter: Brace, + stream: TokenStream [ + Ident { + ident: "Input", + span: #0 bytes(186..191), + }, + ], + span: #0 bytes(135..193), + }, +]