diff options
Diffstat (limited to 'compiler/rustc_parse/src')
| -rw-r--r-- | compiler/rustc_parse/src/errors.rs | 12 | ||||
| -rw-r--r-- | compiler/rustc_parse/src/parser/expr.rs | 13 | ||||
| -rw-r--r-- | compiler/rustc_parse/src/parser/mod.rs | 1 | ||||
| -rw-r--r-- | compiler/rustc_parse/src/parser/pat.rs | 155 |
4 files changed, 168 insertions, 13 deletions
diff --git a/compiler/rustc_parse/src/errors.rs b/compiler/rustc_parse/src/errors.rs index 40852048293..fa91b64d531 100644 --- a/compiler/rustc_parse/src/errors.rs +++ b/compiler/rustc_parse/src/errors.rs @@ -2416,6 +2416,18 @@ pub(crate) struct ExpectedCommaAfterPatternField { } #[derive(Diagnostic)] +#[diag(parse_unexpected_expr_in_pat)] +pub(crate) struct UnexpectedExpressionInPattern { + #[primary_span] + #[label] + pub span: Span, + /// Was a `RangePatternBound` expected? + pub is_bound: bool, + /// Was the unexpected expression a `MethodCallExpression`? + pub is_method_call: bool, +} + +#[derive(Diagnostic)] #[diag(parse_unexpected_paren_in_range_pat)] pub(crate) struct UnexpectedParenInRangePat { #[primary_span] diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs index b789b65797b..c395decab12 100644 --- a/compiler/rustc_parse/src/parser/expr.rs +++ b/compiler/rustc_parse/src/parser/expr.rs @@ -444,6 +444,19 @@ impl<'a> Parser<'a> { ) if self.restrictions.contains(Restrictions::CONST_EXPR) => { return None; } + // When recovering patterns as expressions, stop parsing when encountering an assignment `=`, an alternative `|`, or a range `..`. + ( + Some( + AssocOp::Assign + | AssocOp::AssignOp(_) + | AssocOp::BitOr + | AssocOp::DotDot + | AssocOp::DotDotEq, + ), + _, + ) if self.restrictions.contains(Restrictions::IS_PAT) => { + return None; + } (Some(op), _) => (op, self.token.span), (None, Some((Ident { name: sym::and, span }, false))) if self.may_recover() => { self.dcx().emit_err(errors::InvalidLogicalOperator { diff --git a/compiler/rustc_parse/src/parser/mod.rs b/compiler/rustc_parse/src/parser/mod.rs index ff2fb6271a8..623407eb380 100644 --- a/compiler/rustc_parse/src/parser/mod.rs +++ b/compiler/rustc_parse/src/parser/mod.rs @@ -53,6 +53,7 @@ bitflags::bitflags! { const CONST_EXPR = 1 << 2; const ALLOW_LET = 1 << 3; const IN_IF_GUARD = 1 << 4; + const IS_PAT = 1 << 5; } } diff --git a/compiler/rustc_parse/src/parser/pat.rs b/compiler/rustc_parse/src/parser/pat.rs index 7918e03750c..d04921dde54 100644 --- a/compiler/rustc_parse/src/parser/pat.rs +++ b/compiler/rustc_parse/src/parser/pat.rs @@ -1,4 +1,4 @@ -use super::{ForceCollect, Parser, PathStyle, TrailingToken}; +use super::{ForceCollect, Parser, PathStyle, Restrictions, TrailingToken}; use crate::errors::{ self, AmbiguousRangePattern, DotDotDotForRemainingFields, DotDotDotRangeToPatternNotAllowed, DotDotDotRestPattern, EnumPatternInsteadOfIdentifier, ExpectedBindingLeftOfAt, @@ -6,14 +6,14 @@ use crate::errors::{ InclusiveRangeExtraEquals, InclusiveRangeMatchArrow, InclusiveRangeNoEnd, InvalidMutInPattern, PatternOnWrongSideOfAt, RefMutOrderIncorrect, RemoveLet, RepeatedMutInPattern, SwitchRefBoxOrder, TopLevelOrPatternNotAllowed, TopLevelOrPatternNotAllowedSugg, - TrailingVertNotAllowed, UnexpectedLifetimeInPattern, UnexpectedParenInRangePat, - UnexpectedParenInRangePatSugg, UnexpectedVertVertBeforeFunctionParam, - UnexpectedVertVertInPattern, + TrailingVertNotAllowed, UnexpectedExpressionInPattern, UnexpectedLifetimeInPattern, + UnexpectedParenInRangePat, UnexpectedParenInRangePatSugg, + UnexpectedVertVertBeforeFunctionParam, UnexpectedVertVertInPattern, }; use crate::{maybe_recover_from_interpolated_ty_qpath, maybe_whole}; use rustc_ast::mut_visit::{noop_visit_pat, MutVisitor}; use rustc_ast::ptr::P; -use rustc_ast::token::{self, Delimiter}; +use rustc_ast::token::{self, BinOpToken, Delimiter, Token}; use rustc_ast::{ self as ast, AttrVec, BindingAnnotation, ByRef, Expr, ExprKind, MacCall, Mutability, Pat, PatField, PatFieldsRest, PatKind, Path, QSelf, RangeEnd, RangeSyntax, @@ -23,7 +23,7 @@ use rustc_errors::{Applicability, DiagnosticBuilder, PResult}; use rustc_session::errors::ExprParenthesesNeeded; use rustc_span::source_map::{respan, Spanned}; use rustc_span::symbol::{kw, sym, Ident}; -use rustc_span::Span; +use rustc_span::{ErrorGuaranteed, Span}; use thin_vec::{thin_vec, ThinVec}; #[derive(PartialEq, Copy, Clone)] @@ -336,6 +336,95 @@ impl<'a> Parser<'a> { } } + /// Ensures that the last parsed pattern (or pattern range bound) is not followed by a method call or an operator. + /// + /// `is_end_bound` indicates whether the last parsed thing was the end bound of a range pattern (see [`parse_pat_range_end`](Self::parse_pat_range_end)) + /// in order to say "expected a pattern range bound" instead of "expected a pattern"; + /// ```text + /// 0..=1 + 2 + /// ^^^^^ + /// ``` + /// Only the end bound is spanned, and this function have no idea if there were a `..=` before `pat_span`, hence the parameter. + #[must_use = "the pattern must be discarded as `PatKind::Err` if this function returns Some"] + fn maybe_recover_trailing_expr( + &mut self, + pat_span: Span, + is_end_bound: bool, + ) -> Option<ErrorGuaranteed> { + if self.prev_token.is_keyword(kw::Underscore) || !self.may_recover() { + // Don't recover anything after an `_` or if recovery is disabled. + return None; + } + + // Check for `.hello()`, but allow `.Hello()` to be recovered as `, Hello()` in `parse_seq_to_before_tokens()`. + let has_trailing_method = self.check_noexpect(&token::Dot) + && self.look_ahead(1, |tok| { + tok.ident() + .and_then(|(ident, _)| ident.name.as_str().chars().next()) + .is_some_and(char::is_lowercase) + }) + && self.look_ahead(2, |tok| tok.kind == token::OpenDelim(Delimiter::Parenthesis)); + + // Check for operators. + // `|` is excluded as it is used in pattern alternatives and lambdas, + // `?` is included for error propagation, + // `[` is included for indexing operations, + // `[]` is excluded as `a[]` isn't an expression and should be recovered as `a, []` (cf. `tests/ui/parser/pat-lt-bracket-7.rs`) + let has_trailing_operator = matches!(self.token.kind, token::BinOp(op) if op != BinOpToken::Or) + || self.token.kind == token::Question + || (self.token.kind == token::OpenDelim(Delimiter::Bracket) + && self.look_ahead(1, |tok| tok.kind != token::CloseDelim(Delimiter::Bracket))); + + if !has_trailing_method && !has_trailing_operator { + // Nothing to recover here. + return None; + } + + // Let's try to parse an expression to emit a better diagnostic. + let mut snapshot = self.create_snapshot_for_diagnostic(); + snapshot.restrictions.insert(Restrictions::IS_PAT); + + // Parse `?`, `.f`, `(arg0, arg1, ...)` or `[expr]` until they've all been eaten. + if let Ok(expr) = snapshot + .parse_expr_dot_or_call_with( + self.mk_expr_err(pat_span), // equivalent to transforming the parsed pattern into an `Expr` + pat_span, + AttrVec::new(), + ) + .map_err(|err| err.cancel()) + { + let non_assoc_span = expr.span; + + // Parse an associative expression such as `+ expr`, `% expr`, ... + // Assignements, ranges and `|` are disabled by [`Restrictions::IS_PAT`]. + if let Ok(expr) = + snapshot.parse_expr_assoc_with(0, expr.into()).map_err(|err| err.cancel()) + { + // We got a valid expression. + self.restore_snapshot(snapshot); + self.restrictions.remove(Restrictions::IS_PAT); + + let is_bound = is_end_bound + // is_start_bound: either `..` or `)..` + || self.token.is_range_separator() + || self.token.kind == token::CloseDelim(Delimiter::Parenthesis) + && self.look_ahead(1, Token::is_range_separator); + + // Check that `parse_expr_assoc_with` didn't eat a rhs. + let is_method_call = has_trailing_method && non_assoc_span == expr.span; + + return Some(self.dcx().emit_err(UnexpectedExpressionInPattern { + span: expr.span, + is_bound, + is_method_call, + })); + } + } + + // We got a trailing method/operator, but we couldn't parse an expression. + None + } + /// Parses a pattern, with a setting whether modern range patterns (e.g., `a..=b`, `a..b` are /// allowed). fn parse_pat_with_range_pat( @@ -441,7 +530,10 @@ impl<'a> Parser<'a> { } else if self.check(&token::OpenDelim(Delimiter::Parenthesis)) { self.parse_pat_tuple_struct(qself, path)? } else { - PatKind::Path(qself, path) + match self.maybe_recover_trailing_expr(span, false) { + Some(guar) => PatKind::Err(guar), + None => PatKind::Path(qself, path), + } } } else if matches!(self.token.kind, token::Lifetime(_)) // In pattern position, we're totally fine with using "next token isn't colon" @@ -470,10 +562,17 @@ impl<'a> Parser<'a> { } else { // Try to parse everything else as literal with optional minus match self.parse_literal_maybe_minus() { - Ok(begin) => match self.parse_range_end() { - Some(form) => self.parse_pat_range_begin_with(begin, form)?, - None => PatKind::Lit(begin), - }, + Ok(begin) => { + let begin = match self.maybe_recover_trailing_expr(begin.span, false) { + Some(_) => self.mk_expr_err(begin.span), + None => begin, + }; + + match self.parse_range_end() { + Some(form) => self.parse_pat_range_begin_with(begin, form)?, + None => PatKind::Lit(begin), + } + } Err(err) => return self.fatal_unexpected_non_pat(err, expected), } }; @@ -615,6 +714,21 @@ impl<'a> Parser<'a> { self.parse_pat_range_begin_with(begin.clone(), form)? } + // recover ranges with parentheses around the `(start)..` + PatKind::Err(_) + if self.may_recover() + && let Some(form) = self.parse_range_end() => + { + self.dcx().emit_err(UnexpectedParenInRangePat { + span: vec![open_paren, close_paren], + sugg: UnexpectedParenInRangePatSugg { + start_span: open_paren, + end_span: close_paren, + }, + }); + + self.parse_pat_range_begin_with(self.mk_expr(pat.span, ExprKind::Err), form)? + } // (pat) with optional parentheses _ => PatKind::Paren(pat), @@ -853,6 +967,8 @@ impl<'a> Parser<'a> { self.parse_literal_maybe_minus() }?; + let recovered = self.maybe_recover_trailing_expr(bound.span, true); + // recover trailing `)` if let Some(open_paren) = open_paren { self.expect(&token::CloseDelim(Delimiter::Parenthesis))?; @@ -866,7 +982,10 @@ impl<'a> Parser<'a> { }); } - Ok(bound) + Ok(match recovered { + Some(_) => self.mk_expr_err(bound.span), + None => bound, + }) } /// Is this the start of a pattern beginning with a path? @@ -929,7 +1048,17 @@ impl<'a> Parser<'a> { .create_err(EnumPatternInsteadOfIdentifier { span: self.prev_token.span })); } - Ok(PatKind::Ident(binding_annotation, ident, sub)) + // Check for method calls after the `ident`, + // but not `ident @ subpat` as `subpat` was already checked and `ident` continues with `@`. + + let pat = if sub.is_none() + && let Some(guar) = self.maybe_recover_trailing_expr(ident.span, false) + { + PatKind::Err(guar) + } else { + PatKind::Ident(binding_annotation, ident, sub) + }; + Ok(pat) } /// Parse a struct ("record") pattern (e.g. `Foo { ... }` or `Foo::Bar { ... }`). |