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[WIP] undo #49719 for rust 2015 with feature flag #51336

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[WIP] undo #49719 for rust 2015 with feature flag #51336

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20 changes: 16 additions & 4 deletions src/libsyntax/ext/tt/macro_rules.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -240,8 +240,14 @@ pub fn compile(sess: &ParseSess, features: &Features, def: &ast::Item, edition:
s.iter().map(|m| {
if let MatchedNonterminal(ref nt) = *m {
if let NtTT(ref tt) = **nt {
let tt = quoted::parse(tt.clone().into(), true, sess, features, &def.attrs)
.pop().unwrap();
let tt = quoted::parse(
tt.clone().into(),
true,
sess,
features,
&def.attrs,
edition
).pop().unwrap();
valid &= check_lhs_nt_follows(sess, features, &def.attrs, &tt);
return tt;
}
Expand All @@ -257,8 +263,14 @@ pub fn compile(sess: &ParseSess, features: &Features, def: &ast::Item, edition:
s.iter().map(|m| {
if let MatchedNonterminal(ref nt) = *m {
if let NtTT(ref tt) = **nt {
return quoted::parse(tt.clone().into(), false, sess, features, &def.attrs)
.pop().unwrap();
return quoted::parse(
tt.clone().into(),
false,
sess,
features,
&def.attrs,
edition
).pop().unwrap();
}
}
sess.span_diagnostic.span_bug(def.span, "wrong-structured lhs")
Expand Down
114 changes: 67 additions & 47 deletions src/libsyntax/ext/tt/quoted.rs
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -10,11 +10,11 @@

use {ast, attr};
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::{BytePos, Span, DUMMY_SP};
use syntax_pos::{BytePos, Span, DUMMY_SP, edition::Edition};
use tokenstream;

use std::iter::Peekable;
Expand Down Expand Up @@ -184,6 +184,7 @@ pub fn parse(
sess: &ParseSess,
features: &Features,
attrs: &[ast::Attribute],
edition: Edition,
) -> Vec<TokenTree> {
// Will contain the final collection of `self::TokenTree`
let mut result = Vec::new();
Expand All @@ -194,7 +195,7 @@ pub fn parse(
while let Some(tree) = trees.next() {
// Given the parsed tree, if there is a metavar and we are expecting matchers, actually
// parse out the matcher (i.e. in `$id:ident` this would parse the `:` and `ident`).
let tree = parse_tree(tree, &mut trees, expect_matchers, sess, features, attrs);
let tree = parse_tree(tree, &mut trees, expect_matchers, sess, features, attrs, edition);
match tree {
TokenTree::MetaVar(start_sp, ident) if expect_matchers => {
let span = match trees.next() {
Expand Down Expand Up @@ -252,6 +253,7 @@ fn parse_tree<I>(
sess: &ParseSess,
features: &Features,
attrs: &[ast::Attribute],
edition: Edition,
) -> TokenTree
where
I: Iterator<Item = tokenstream::TokenTree>,
Expand All @@ -270,9 +272,23 @@ where
sess.span_diagnostic.span_err(span, &msg);
}
// Parse the contents of the sequence itself
let sequence = parse(delimited.tts.into(), expect_matchers, sess, features, attrs);
let sequence = parse(
delimited.tts.into(),
expect_matchers,
sess,
features,
attrs,
edition,
);
// Get the Kleene operator and optional separator
let (separator, op) = parse_sep_and_kleene_op(trees, span, sess, features, attrs);
let (separator, op) = parse_sep_and_kleene_op(
trees,
span,
sess,
features,
attrs,
edition
);
// Count the number of captured "names" (i.e. named metavars)
let name_captures = macro_parser::count_names(&sequence);
TokenTree::Sequence(
Expand Down Expand Up @@ -322,19 +338,46 @@ where
span,
Lrc::new(Delimited {
delim: delimited.delim,
tts: parse(delimited.tts.into(), expect_matchers, sess, features, attrs),
tts: parse(
delimited.tts.into(),
expect_matchers,
sess,
features,
attrs,
edition
),
}),
),
}
}

/// Takes a token and returns `Some(KleeneOp)` if the token is `+` `*` or `?`. Otherwise, return
/// `None`.
fn kleene_op(token: &token::Token) -> Option<KleeneOp> {
/// `None`. This function takes into account what edition and feature flags are enabled.
fn kleene_op(
token: &token::Token,
span: Span,
sess: &ParseSess,
edition: Edition,
features: &Features,
attrs: &[ast::Attribute],
) -> Option<KleeneOp> {
match *token {
token::BinOp(token::Star) => Some(KleeneOp::ZeroOrMore),
token::BinOp(token::Plus) => Some(KleeneOp::OneOrMore),
token::Question => Some(KleeneOp::ZeroOrOne),
token::Question =>
if edition >= Edition::Edition2018
|| (features.macro_at_most_once_rep
&& attr::contains_name(attrs, "allow_internal_unstable")) {
Some(KleeneOp::ZeroOrOne)
} else {
sess.span_diagnostic
.span_warn(
span,
"`?` as a separator is deprecated and \
will be removed in an upcoming edition."
);
None
},
_ => None,
}
}
Expand All @@ -347,14 +390,20 @@ fn kleene_op(token: &token::Token) -> Option<KleeneOp> {
fn parse_kleene_op<I>(
input: &mut I,
span: Span,
sess: &ParseSess,
edition: Edition,
features: &Features,
attrs: &[ast::Attribute],
) -> Result<Result<KleeneOp, (token::Token, Span)>, Span>
where
I: Iterator<Item = tokenstream::TokenTree>,
{
match input.next() {
Some(tokenstream::TokenTree::Token(span, tok)) => match kleene_op(&tok) {
Some(op) => Ok(Ok(op)),
None => Ok(Err((tok, span))),
Some(tokenstream::TokenTree::Token(span, tok)) => {
match kleene_op(&tok, span, sess, edition, features, attrs) {
Some(op) => Ok(Ok(op)),
None => Ok(Err((tok, span))),
}
},
tree => Err(tree.as_ref()
.map(tokenstream::TokenTree::span)
Expand All @@ -380,51 +429,22 @@ fn parse_sep_and_kleene_op<I>(
sess: &ParseSess,
features: &Features,
attrs: &[ast::Attribute],
edition: Edition,
) -> (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 any KleeneOp (`?`)
Ok(Ok(op)) 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",
span,
GateIssue::Language,
explain,
);
}
return (None, op);
}

// #1 is any KleeneOp (`+`, `*`)
let span = match parse_kleene_op(input, span, sess, edition, features, attrs) {
// #1 is any KleeneOp (`+`, `*`, or `?` (on editions > 2015))
Ok(Ok(op)) => return (None, op),

// #1 is a separator followed by #2, a KleeneOp
Ok(Err((tok, span))) => match parse_kleene_op(input, span) {
Ok(Err((tok, span))) => match parse_kleene_op(input, span, sess, edition, features, attrs) {
// #2 is a KleeneOp :D
Ok(Ok(op)) 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",
span,
GateIssue::Language,
explain,
);
} else {
sess.span_diagnostic
.span_err(span, "`?` macro repetition does not allow a separator");
}
sess.span_diagnostic
.span_err(span, "`?` macro repetition does not allow a separator");
return (None, op);
}
Ok(Ok(op)) => return (Some(tok), op),
Expand Down