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Rollup merge of #106242 - estebank:diff-markers, r=jyn514

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Detect diff markers in the parser

Partly address #32059.
This commit is contained in:
Matthias Krüger 2022-12-29 13:16:06 +01:00 • committed by GitHub
commit 031a2143f0
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26 changed files with 438 additions and 5 deletions
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72
compiler/rustc_parse/src/parser/diagnostics.rs
View file

@ -31,7 +31,8 @@ use rustc_ast::{
use rustc_ast_pretty::pprust;
use rustc_data_structures::fx::FxHashSet;
use rustc_errors::{
fluent, Applicability, DiagnosticBuilder, DiagnosticMessage, Handler, MultiSpan, PResult,
fluent, Applicability, DiagnosticBuilder, DiagnosticMessage, FatalError, Handler, MultiSpan,
PResult,
};
use rustc_errors::{pluralize, Diagnostic, ErrorGuaranteed, IntoDiagnostic};
use rustc_session::errors::ExprParenthesesNeeded;
@ -2556,6 +2557,75 @@ impl<'a> Parser<'a> {
Ok(())
}
pub fn is_diff_marker(&mut self, long_kind: &TokenKind, short_kind: &TokenKind) -> bool {
(0..3).all(|i| self.look_ahead(i, |tok| tok == long_kind))
&& self.look_ahead(3, |tok| tok == short_kind)
}
fn diff_marker(&mut self, long_kind: &TokenKind, short_kind: &TokenKind) -> Option<Span> {
if self.is_diff_marker(long_kind, short_kind) {
let lo = self.token.span;
for _ in 0..4 {
self.bump();
}
return Some(lo.to(self.prev_token.span));
}
None
}
pub fn recover_diff_marker(&mut self) {
let Some(start) = self.diff_marker(&TokenKind::BinOp(token::Shl), &TokenKind::Lt) else {
return;
};
let mut spans = Vec::with_capacity(3);
spans.push(start);
let mut middlediff3 = None;
let mut middle = None;
let mut end = None;
loop {
if self.token.kind == TokenKind::Eof {
break;
}
if let Some(span) = self.diff_marker(&TokenKind::OrOr, &TokenKind::BinOp(token::Or)) {
middlediff3 = Some(span);
}
if let Some(span) = self.diff_marker(&TokenKind::EqEq, &TokenKind::Eq) {
middle = Some(span);
}
if let Some(span) = self.diff_marker(&TokenKind::BinOp(token::Shr), &TokenKind::Gt) {
spans.push(span);
end = Some(span);
break;
}
self.bump();
}
let mut err = self.struct_span_err(spans, "encountered diff marker");
err.span_label(start, "after this is the code before the merge");
if let Some(middle) = middlediff3 {
err.span_label(middle, "");
}
if let Some(middle) = middle {
err.span_label(middle, "");
}
if let Some(end) = end {
err.span_label(end, "above this are the incoming code changes");
}
err.help(
"if you're having merge conflicts after pulling new code, the top section is the code \
you already had and the bottom section is the remote code",
);
err.help(
"if you're in the middle of a rebase, the top section is the code being rebased onto \
and the bottom section is the code coming from the current commit being rebased",
);
err.note(
"for an explanation on these markers from the `git` documentation, visit \
<https://git-scm.com/book/en/v2/Git-Tools-Advanced-Merging#_checking_out_conflicts>",
);
err.emit();
FatalError.raise()
}
/// Parse and throw away a parenthesized comma separated
/// sequence of patterns until `)` is reached.
fn skip_pat_list(&mut self) -> PResult<'a, ()> {

1
compiler/rustc_parse/src/parser/expr.rs
View file

@ -3039,6 +3039,7 @@ impl<'a> Parser<'a> {
/// Parses `ident (COLON expr)?`.
fn parse_expr_field(&mut self) -> PResult<'a, ExprField> {
let attrs = self.parse_outer_attributes()?;
self.recover_diff_marker();
self.collect_tokens_trailing_token(attrs, ForceCollect::No, |this, attrs| {
let lo = this.token.span;

42
compiler/rustc_parse/src/parser/item.rs
View file

@ -98,7 +98,9 @@ impl<'a> Parser<'a> {
fn_parse_mode: FnParseMode,
force_collect: ForceCollect,
) -> PResult<'a, Option<Item>> {
self.recover_diff_marker();
let attrs = self.parse_outer_attributes()?;
self.recover_diff_marker();
self.parse_item_common(attrs, true, false, fn_parse_mode, force_collect)
}
@ -704,6 +706,7 @@ impl<'a> Parser<'a> {
if self.recover_doc_comment_before_brace() {
continue;
}
self.recover_diff_marker();
match parse_item(self) {
Ok(None) => {
let mut is_unnecessary_semicolon = !items.is_empty()
@ -1039,8 +1042,11 @@ impl<'a> Parser<'a> {
/// USE_TREE_LIST = Ø | (USE_TREE `,`)* USE_TREE [`,`]
/// ```
fn parse_use_tree_list(&mut self) -> PResult<'a, Vec<(UseTree, ast::NodeId)>> {
self.parse_delim_comma_seq(Delimiter::Brace, |p| Ok((p.parse_use_tree()?, DUMMY_NODE_ID)))
.map(|(r, _)| r)
self.parse_delim_comma_seq(Delimiter::Brace, |p| {
p.recover_diff_marker();
Ok((p.parse_use_tree()?, DUMMY_NODE_ID))
})
.map(|(r, _)| r)
}
fn parse_rename(&mut self) -> PResult<'a, Option<Ident>> {
@ -1379,7 +1385,9 @@ impl<'a> Parser<'a> {
}
fn parse_enum_variant(&mut self) -> PResult<'a, Option<Variant>> {
self.recover_diff_marker();
let variant_attrs = self.parse_outer_attributes()?;
self.recover_diff_marker();
self.collect_tokens_trailing_token(
variant_attrs,
ForceCollect::No,
@ -1573,9 +1581,32 @@ impl<'a> Parser<'a> {
self.parse_paren_comma_seq(|p| {
let attrs = p.parse_outer_attributes()?;
p.collect_tokens_trailing_token(attrs, ForceCollect::No, |p, attrs| {
let mut snapshot = None;
if p.is_diff_marker(&TokenKind::BinOp(token::Shl), &TokenKind::Lt) {
// Account for `<<<<<<<` diff markers. We can't proactively error here because
// that can be a valid type start, so we snapshot and reparse only we've
// encountered another parse error.
snapshot = Some(p.create_snapshot_for_diagnostic());
}
let lo = p.token.span;
let vis = p.parse_visibility(FollowedByType::Yes)?;
let ty = p.parse_ty()?;
let vis = match p.parse_visibility(FollowedByType::Yes) {
Ok(vis) => vis,
Err(err) => {
if let Some(ref mut snapshot) = snapshot {
snapshot.recover_diff_marker();
}
return Err(err);
}
};
let ty = match p.parse_ty() {
Ok(ty) => ty,
Err(err) => {
if let Some(ref mut snapshot) = snapshot {
snapshot.recover_diff_marker();
}
return Err(err);
}
};
Ok((
FieldDef {
@ -1596,7 +1627,9 @@ impl<'a> Parser<'a> {
/// Parses an element of a struct declaration.
fn parse_field_def(&mut self, adt_ty: &str) -> PResult<'a, FieldDef> {
self.recover_diff_marker();
let attrs = self.parse_outer_attributes()?;
self.recover_diff_marker();
self.collect_tokens_trailing_token(attrs, ForceCollect::No, |this, attrs| {
let lo = this.token.span;
let vis = this.parse_visibility(FollowedByType::No)?;
@ -2427,6 +2460,7 @@ impl<'a> Parser<'a> {
let mut first_param = true;
// Parse the arguments, starting out with `self` being allowed...
let (mut params, _) = self.parse_paren_comma_seq(|p| {
p.recover_diff_marker();
let param = p.parse_param_general(req_name, first_param).or_else(|mut e| {
e.emit();
let lo = p.prev_token.span;

10
compiler/rustc_parse/src/parser/stmt.rs
View file

@ -531,13 +531,23 @@ impl<'a> Parser<'a> {
recover: AttemptLocalParseRecovery,
) -> PResult<'a, P<Block>> {
let mut stmts = vec![];
let mut snapshot = None;
while !self.eat(&token::CloseDelim(Delimiter::Brace)) {
if self.token == token::Eof {
break;
}
if self.is_diff_marker(&TokenKind::BinOp(token::Shl), &TokenKind::Lt) {
// Account for `<<<<<<<` diff markers. We can't proactively error here because
// that can be a valid path start, so we snapshot and reparse only we've
// encountered another parse error.
snapshot = Some(self.create_snapshot_for_diagnostic());
}
let stmt = match self.parse_full_stmt(recover) {
Err(mut err) if recover.yes() => {
self.maybe_annotate_with_ascription(&mut err, false);
if let Some(ref mut snapshot) = snapshot {
snapshot.recover_diff_marker();
}
err.emit();
self.recover_stmt_(SemiColonMode::Ignore, BlockMode::Ignore);
Some(self.mk_stmt_err(self.token.span))