bjoernager/rust
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Implement edition-based macro pat feature

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This commit is contained in:
mark 2020-12-28 16:57:13 -06:00
parent 2987785df3
commit 40bf3c0f09
12 changed files with 151 additions and 76 deletions
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24
compiler/rustc_expand/src/mbe/macro_parser.rs
View file

@ -77,9 +77,9 @@ use TokenTreeOrTokenTreeSlice::*;
use crate::mbe::{self, TokenTree};
use rustc_ast::token::{self, DocComment, Nonterminal, Token};
use rustc_parse::parser::{OrPatNonterminalMode, Parser};
use rustc_parse::parser::Parser;
use rustc_session::parse::ParseSess;
use rustc_span::{edition::Edition, symbol::MacroRulesNormalizedIdent};
use rustc_span::symbol::MacroRulesNormalizedIdent;
use smallvec::{smallvec, SmallVec};
@ -419,18 +419,6 @@ fn token_name_eq(t1: &Token, t2: &Token) -> bool {
}
}
/// In edition 2015/18, `:pat` can only match `pat<no_top_alt>` because otherwise, we have
/// breakage. As of edition 2021, `:pat` matches `top_pat`.
///
/// See <https://github.com/rust-lang/rust/issues/54883> for more info.
fn or_pat_mode(edition: Edition) -> OrPatNonterminalMode {
match edition {
Edition::Edition2015 | Edition::Edition2018 => OrPatNonterminalMode::NoTopAlt,
// FIXME(mark-i-m): uncomment this when edition 2021 machinery is added.
// Edition::Edition2021 => OrPatNonterminalMode::TopPat,
}
}
/// Process the matcher positions of `cur_items` until it is empty. In the process, this will
/// produce more items in `next_items`, `eof_items`, and `bb_items`.
///
@ -578,14 +566,13 @@ fn inner_parse_loop<'root, 'tt>(
// We need to match a metavar with a valid ident... call out to the black-box
// parser by adding an item to `bb_items`.
TokenTree::MetaVarDecl(span, _, Some(kind)) => {
TokenTree::MetaVarDecl(_, _, Some(kind)) => {
// Built-in nonterminals never start with these tokens, so we can eliminate
// them from consideration.
//
// We use the span of the metavariable declaration to determine any
// edition-specific matching behavior for non-terminals.
if Parser::nonterminal_may_begin_with(kind, token, or_pat_mode(span.edition()))
{
if Parser::nonterminal_may_begin_with(kind, token) {
bb_items.push(item);
}
}
@ -749,8 +736,7 @@ pub(super) fn parse_tt(parser: &mut Cow<'_, Parser<'_>>, ms: &[TokenTree]) -> Na
let match_cur = item.match_cur;
// We use the span of the metavariable declaration to determine any
// edition-specific matching behavior for non-terminals.
let nt = match parser.to_mut().parse_nonterminal(kind, or_pat_mode(span.edition()))
{
let nt = match parser.to_mut().parse_nonterminal(kind) {
Err(mut err) => {
err.span_label(
span,

16
compiler/rustc_expand/src/mbe/macro_rules.rs
View file

@ -476,10 +476,15 @@ pub fn compile_declarative_macro(
.map(|m| {
if let MatchedNonterminal(ref nt) = *m {
if let NtTT(ref tt) = **nt {
let tt =
mbe::quoted::parse(tt.clone().into(), true, &sess.parse_sess, def.id)
.pop()
.unwrap();
let tt = mbe::quoted::parse(
tt.clone().into(),
true,
&sess.parse_sess,
def.id,
features,
)
.pop()
.unwrap();
valid &= check_lhs_nt_follows(&sess.parse_sess, features, &def.attrs, &tt);
return tt;
}
@ -501,6 +506,7 @@ pub fn compile_declarative_macro(
false,
&sess.parse_sess,
def.id,
features,
)
.pop()
.unwrap();
@ -1090,7 +1096,7 @@ fn is_in_follow(tok: &mbe::TokenTree, kind: NonterminalKind) -> IsInFollow {
_ => IsInFollow::No(TOKENS),
}
}
NonterminalKind::Pat => {
NonterminalKind::Pat2018 { .. } | NonterminalKind::Pat2021 { .. } => {
const TOKENS: &[&str] = &["`=>`", "`,`", "`=`", "`|`", "`if`", "`in`"];
match tok {
TokenTree::Token(token) => match token.kind {

68
compiler/rustc_expand/src/mbe/quoted.rs
View file

@ -5,8 +5,9 @@ use rustc_ast::token::{self, Token};
use rustc_ast::tokenstream;
use rustc_ast::{NodeId, DUMMY_NODE_ID};
use rustc_ast_pretty::pprust;
use rustc_session::parse::ParseSess;
use rustc_span::symbol::{kw, Ident};
use rustc_feature::Features;
use rustc_session::parse::{feature_err, ParseSess};
use rustc_span::symbol::{kw, sym, Ident};
use rustc_span::Span;
@ -29,10 +30,8 @@ const VALID_FRAGMENT_NAMES_MSG: &str = "valid fragment specifiers are \
/// `ident` are "matchers". They are not present in the body of a macro rule -- just in the
/// pattern, so we pass a parameter to indicate whether to expect them or not.
/// - `sess`: the parsing session. Any errors will be emitted to this session.
/// - `features`, `attrs`: language feature flags and attributes so that we know whether to use
/// unstable features or not.
/// - `edition`: which edition are we in.
/// - `macro_node_id`: the NodeId of the macro we are parsing.
/// - `node_id`: the NodeId of the macro we are parsing.
/// - `features`: language features so we can do feature gating.
///
/// # Returns
///
@ -42,6 +41,7 @@ pub(super) fn parse(
expect_matchers: bool,
sess: &ParseSess,
node_id: NodeId,
features: &Features,
) -> Vec<TokenTree> {
// Will contain the final collection of `self::TokenTree`
let mut result = Vec::new();
@ -52,7 +52,7 @@ pub(super) 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, node_id);
let tree = parse_tree(tree, &mut trees, expect_matchers, sess, node_id, features);
match tree {
TokenTree::MetaVar(start_sp, ident) if expect_matchers => {
let span = match trees.next() {
@ -61,18 +61,39 @@ pub(super) fn parse(
Some(tokenstream::TokenTree::Token(token)) => match token.ident() {
Some((frag, _)) => {
let span = token.span.with_lo(start_sp.lo());
let kind = token::NonterminalKind::from_symbol(frag.name)
.unwrap_or_else(|| {
let msg = format!(
"invalid fragment specifier `{}`",
frag.name
);
sess.span_diagnostic
.struct_span_err(span, &msg)
.help(VALID_FRAGMENT_NAMES_MSG)
match frag.name {
sym::pat2018 | sym::pat2021 => {
if !features.edition_macro_pats {
feature_err(
sess,
sym::edition_macro_pats,
frag.span,
"`pat2018` and `pat2021` are unstable.",
)
.emit();
token::NonterminalKind::Ident
});
}
}
_ => {}
}
let kind =
token::NonterminalKind::from_symbol(frag.name, || {
span.edition()
})
.unwrap_or_else(
|| {
let msg = format!(
"invalid fragment specifier `{}`",
frag.name
);
sess.span_diagnostic
.struct_span_err(span, &msg)
.help(VALID_FRAGMENT_NAMES_MSG)
.emit();
token::NonterminalKind::Ident
},
);
result.push(TokenTree::MetaVarDecl(span, ident, Some(kind)));
continue;
}
@ -110,14 +131,14 @@ pub(super) fn parse(
/// converting `tree`
/// - `expect_matchers`: same as for `parse` (see above).
/// - `sess`: the parsing session. Any errors will be emitted to this session.
/// - `features`, `attrs`: language feature flags and attributes so that we know whether to use
/// unstable features or not.
/// - `features`: language features so we can do feature gating.
fn parse_tree(
tree: tokenstream::TokenTree,
outer_trees: &mut impl Iterator<Item = tokenstream::TokenTree>,
expect_matchers: bool,
sess: &ParseSess,
node_id: NodeId,
features: &Features,
) -> TokenTree {
// Depending on what `tree` is, we could be parsing different parts of a macro
match tree {
@ -145,7 +166,7 @@ fn parse_tree(
sess.span_diagnostic.span_err(span.entire(), &msg);
}
// Parse the contents of the sequence itself
let sequence = parse(tts, expect_matchers, sess, node_id);
let sequence = parse(tts, expect_matchers, sess, node_id, features);
// Get the Kleene operator and optional separator
let (separator, kleene) =
parse_sep_and_kleene_op(&mut trees, span.entire(), sess);
@ -196,7 +217,10 @@ fn parse_tree(
// descend into the delimited set and further parse it.
tokenstream::TokenTree::Delimited(span, delim, tts) => TokenTree::Delimited(
span,
Lrc::new(Delimited { delim, tts: parse(tts, expect_matchers, sess, node_id) }),
Lrc::new(Delimited {
delim,
tts: parse(tts, expect_matchers, sess, node_id, features),
}),
),
}
}