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Auto merge of #56245 - mark-i-m:stabilize_ques_kleene, r=alexcrichton
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Stabilize feature `macro_at_most_once_rep`

a.k.a. `?` Kleene operator 🎉

cc #48075

r? @Centril
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bors committed Nov 29, 2018
2 parents a49316d + 5d77173 commit 5a03532
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Showing 24 changed files with 32 additions and 279 deletions.

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1 change: 0 additions & 1 deletion src/doc/unstable-book/src/language-features/plugin.md
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Expand Up @@ -181,7 +181,6 @@ that warns about any item named `lintme`.
```rust,ignore
#![feature(plugin_registrar)]
#![feature(box_syntax, rustc_private)]
#![feature(macro_at_most_once_rep)]
extern crate syntax;
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1 change: 0 additions & 1 deletion src/libcore/lib.rs
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Expand Up @@ -93,7 +93,6 @@
#![feature(never_type)]
#![feature(nll)]
#![feature(exhaustive_patterns)]
#![feature(macro_at_most_once_rep)]
#![feature(no_core)]
#![feature(on_unimplemented)]
#![feature(optin_builtin_traits)]
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1 change: 0 additions & 1 deletion src/librustc/lib.rs
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Expand Up @@ -67,7 +67,6 @@
#![feature(integer_atomics)]
#![feature(test)]
#![feature(in_band_lifetimes)]
#![feature(macro_at_most_once_rep)]
#![feature(crate_visibility_modifier)]
#![feature(transpose_result)]

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1 change: 0 additions & 1 deletion src/librustc_lint/lib.rs
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Expand Up @@ -29,7 +29,6 @@
#![feature(nll)]
#![feature(quote)]
#![feature(rustc_diagnostic_macros)]
#![feature(macro_at_most_once_rep)]

#[macro_use]
extern crate syntax;
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1 change: 0 additions & 1 deletion src/librustc_metadata/lib.rs
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Expand Up @@ -14,7 +14,6 @@

#![feature(box_patterns)]
#![feature(libc)]
#![feature(macro_at_most_once_rep)]
#![feature(nll)]
#![feature(proc_macro_internals)]
#![feature(proc_macro_quote)]
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58 changes: 13 additions & 45 deletions src/libsyntax/ext/tt/quoted.rs
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Expand Up @@ -11,13 +11,13 @@
use ast::NodeId;
use early_buffered_lints::BufferedEarlyLintId;
use ext::tt::macro_parser;
use feature_gate::{self, emit_feature_err, Features, GateIssue};
use feature_gate::Features;
use parse::{token, ParseSess};
use print::pprust;
use symbol::keywords;
use syntax_pos::{edition::Edition, BytePos, Span};
use tokenstream::{self, DelimSpan};
use {ast, attr};
use ast;

use rustc_data_structures::sync::Lrc;
use std::iter::Peekable;
Expand Down Expand Up @@ -566,32 +566,17 @@ fn parse_sep_and_kleene_op_2018<I>(
input: &mut Peekable<I>,
span: Span,
sess: &ParseSess,
features: &Features,
attrs: &[ast::Attribute],
_features: &Features,
_attrs: &[ast::Attribute],
) -> (Option<token::Token>, KleeneOp)
where
I: Iterator<Item = tokenstream::TokenTree>,
{
// We basically look at two token trees here, denoted as #1 and #2 below
let span = match parse_kleene_op(input, span) {
// #1 is a `?` (needs feature gate)
Ok(Ok((op, op1_span))) if op == KleeneOp::ZeroOrOne => {
if !features.macro_at_most_once_rep
&& !attr::contains_name(attrs, "allow_internal_unstable")
{
let explain = feature_gate::EXPLAIN_MACRO_AT_MOST_ONCE_REP;
emit_feature_err(
sess,
"macro_at_most_once_rep",
op1_span,
GateIssue::Language,
explain,
);

op1_span
} else {
return (None, op);
}
Ok(Ok((op, _op1_span))) if op == KleeneOp::ZeroOrOne => {
return (None, op);
}

// #1 is a `+` or `*` KleeneOp
Expand All @@ -600,24 +585,12 @@ where
// #1 is a separator followed by #2, a KleeneOp
Ok(Err((tok, span))) => match parse_kleene_op(input, span) {
// #2 is the `?` Kleene op, which does not take a separator (error)
Ok(Ok((op, op2_span))) if op == KleeneOp::ZeroOrOne => {
Ok(Ok((op, _op2_span))) if op == KleeneOp::ZeroOrOne => {
// Error!

if !features.macro_at_most_once_rep
&& !attr::contains_name(attrs, "allow_internal_unstable")
{
// FIXME: when `?` as a Kleene op is stabilized, we only need the "does not
// take a macro separator" error (i.e. the `else` case).
sess.span_diagnostic
.struct_span_err(op2_span, "expected `*` or `+`")
.note("`?` is not a macro repetition operator")
.emit();
} else {
sess.span_diagnostic.span_err(
span,
"the `?` macro repetition operator does not take a separator",
);
}
sess.span_diagnostic.span_err(
span,
"the `?` macro repetition operator does not take a separator",
);

// Return a dummy
return (None, KleeneOp::ZeroOrMore);
Expand All @@ -638,13 +611,8 @@ where
};

// If we ever get to this point, we have experienced an "unexpected token" error

if !features.macro_at_most_once_rep && !attr::contains_name(attrs, "allow_internal_unstable") {
sess.span_diagnostic.span_err(span, "expected `*` or `+`");
} else {
sess.span_diagnostic
.span_err(span, "expected one of: `*`, `+`, or `?`");
}
sess.span_diagnostic
.span_err(span, "expected one of: `*`, `+`, or `?`");

// Return a dummy
(None, KleeneOp::ZeroOrMore)
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8 changes: 2 additions & 6 deletions src/libsyntax/feature_gate.rs
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Expand Up @@ -393,9 +393,6 @@ declare_features! (
// `extern` in paths
(active, extern_in_paths, "1.23.0", Some(55600), None),

// Use `?` as the Kleene "at most one" operator
(active, macro_at_most_once_rep, "1.25.0", Some(48075), None),

// Infer static outlives requirements; RFC 2093
(active, infer_static_outlives_requirements, "1.26.0", Some(54185), None),

Expand Down Expand Up @@ -689,6 +686,8 @@ declare_features! (
(accepted, extern_crate_item_prelude, "1.31.0", Some(55599), None),
// Allows use of the :literal macro fragment specifier (RFC 1576)
(accepted, macro_literal_matcher, "1.31.0", Some(35625), None),
// Use `?` as the Kleene "at most one" operator
(accepted, macro_at_most_once_rep, "1.32.0", Some(48075), None),
);

// If you change this, please modify src/doc/unstable-book as well. You must
Expand Down Expand Up @@ -1427,9 +1426,6 @@ pub const EXPLAIN_DERIVE_UNDERSCORE: &'static str =
pub const EXPLAIN_UNSIZED_TUPLE_COERCION: &'static str =
"unsized tuple coercion is not stable enough for use and is subject to change";

pub const EXPLAIN_MACRO_AT_MOST_ONCE_REP: &'static str =
"using the `?` macro Kleene operator for \"at most one\" repetition is unstable";

struct PostExpansionVisitor<'a> {
context: &'a Context<'a>,
}
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1 change: 0 additions & 1 deletion src/libsyntax/lib.rs
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Expand Up @@ -20,7 +20,6 @@
test(attr(deny(warnings))))]

#![feature(crate_visibility_modifier)]
#![feature(macro_at_most_once_rep)]
#![feature(nll)]
#![feature(rustc_attrs)]
#![feature(rustc_diagnostic_macros)]
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1 change: 0 additions & 1 deletion src/test/compile-fail-fulldeps/auxiliary/lint_for_crate.rs
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Expand Up @@ -12,7 +12,6 @@

#![feature(plugin_registrar, rustc_private)]
#![feature(box_syntax)]
#![feature(macro_at_most_once_rep)]

#[macro_use] extern crate rustc;
extern crate rustc_plugin;
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Original file line number Diff line number Diff line change
Expand Up @@ -12,7 +12,6 @@

#![feature(plugin_registrar)]
#![feature(box_syntax, rustc_private)]
#![feature(macro_at_most_once_rep)]

// Load rustc as a plugin to get macros
#[macro_use]
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Original file line number Diff line number Diff line change
Expand Up @@ -12,7 +12,6 @@

#![feature(plugin_registrar)]
#![feature(box_syntax, rustc_private)]
#![feature(macro_at_most_once_rep)]

extern crate syntax;

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1 change: 0 additions & 1 deletion src/test/run-pass-fulldeps/auxiliary/lint_for_crate.rs
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Expand Up @@ -12,7 +12,6 @@

#![feature(plugin_registrar, rustc_private)]
#![feature(box_syntax)]
#![feature(macro_at_most_once_rep)]

#[macro_use] extern crate rustc;
extern crate rustc_plugin;
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Original file line number Diff line number Diff line change
Expand Up @@ -9,7 +9,6 @@
// except according to those terms.

#![feature(box_syntax, plugin, plugin_registrar, rustc_private)]
#![feature(macro_at_most_once_rep)]
#![crate_type = "dylib"]

#[macro_use]
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2 changes: 0 additions & 2 deletions src/test/run-pass/macros/macro-at-most-once-rep.rs
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Expand Up @@ -22,8 +22,6 @@

// edition:2018

#![feature(macro_at_most_once_rep)]

macro_rules! foo {
($($a:ident)? ; $num:expr) => { {
let mut x = 0;
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1 change: 0 additions & 1 deletion src/test/ui-fulldeps/auxiliary/lint_group_plugin_test.rs
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Expand Up @@ -12,7 +12,6 @@

#![feature(plugin_registrar)]
#![feature(box_syntax, rustc_private)]
#![feature(macro_at_most_once_rep)]

// Load rustc as a plugin to get macros
#[macro_use]
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1 change: 0 additions & 1 deletion src/test/ui-fulldeps/auxiliary/lint_plugin_test.rs
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Expand Up @@ -12,7 +12,6 @@

#![feature(plugin_registrar)]
#![feature(box_syntax, rustc_private)]
#![feature(macro_at_most_once_rep)]

extern crate syntax;

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1 change: 0 additions & 1 deletion src/test/ui-fulldeps/auxiliary/lint_tool_test.rs
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Expand Up @@ -10,7 +10,6 @@

#![feature(plugin_registrar)]
#![feature(box_syntax, rustc_private)]
#![feature(macro_at_most_once_rep)]

extern crate syntax;

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45 changes: 0 additions & 45 deletions src/test/ui/macros/macro-at-most-once-rep-2018-feature-gate.rs

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