diff options
Diffstat (limited to 'compiler/rustc_parse/src/parser/expr.rs')
| -rw-r--r-- | compiler/rustc_parse/src/parser/expr.rs | 212 |
1 files changed, 147 insertions, 65 deletions
diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs index f4cee3a661e..36125e138b2 100644 --- a/compiler/rustc_parse/src/parser/expr.rs +++ b/compiler/rustc_parse/src/parser/expr.rs @@ -9,7 +9,7 @@ use super::{ use crate::errors; use crate::maybe_recover_from_interpolated_ty_qpath; use ast::mut_visit::{noop_visit_expr, MutVisitor}; -use ast::{Path, PathSegment}; +use ast::{GenBlockKind, Path, PathSegment}; use core::mem; use rustc_ast::ptr::P; use rustc_ast::token::{self, Delimiter, Token, TokenKind}; @@ -32,10 +32,10 @@ use rustc_macros::Subdiagnostic; use rustc_session::errors::{report_lit_error, ExprParenthesesNeeded}; use rustc_session::lint::builtin::BREAK_WITH_LABEL_AND_LOOP; use rustc_session::lint::BuiltinLintDiagnostics; -use rustc_span::source_map::{self, Span, Spanned}; +use rustc_span::source_map::{self, Spanned}; use rustc_span::symbol::kw::PathRoot; use rustc_span::symbol::{kw, sym, Ident, Symbol}; -use rustc_span::{BytePos, Pos}; +use rustc_span::{BytePos, Pos, Span}; use thin_vec::{thin_vec, ThinVec}; /// Possibly accepts an `token::Interpolated` expression (a pre-parsed expression @@ -1007,8 +1007,9 @@ impl<'a> Parser<'a> { let span = self.token.span; let sm = self.sess.source_map(); let (span, actual) = match (&self.token.kind, self.subparser_name) { - (token::Eof, Some(_)) if let Ok(actual) = sm.span_to_snippet(sm.next_point(span)) => - (span.shrink_to_hi(), actual.into()), + (token::Eof, Some(_)) if let Ok(actual) = sm.span_to_snippet(sm.next_point(span)) => { + (span.shrink_to_hi(), actual.into()) + } _ => (span, actual), }; self.sess.emit_err(errors::UnexpectedTokenAfterDot { span, actual }); @@ -1440,14 +1441,20 @@ impl<'a> Parser<'a> { } else if this.token.uninterpolated_span().at_least_rust_2018() { // `Span:.at_least_rust_2018()` is somewhat expensive; don't get it repeatedly. if this.check_keyword(kw::Async) { - if this.is_async_block() { + if this.is_gen_block(kw::Async) { // Check for `async {` and `async move {`. - this.parse_async_block() + this.parse_gen_block() } else { this.parse_expr_closure() } } else if this.eat_keyword(kw::Await) { this.recover_incorrect_await_syntax(lo, this.prev_token.span) + } else if this.token.uninterpolated_span().at_least_rust_2024() { + if this.is_gen_block(kw::Gen) { + this.parse_gen_block() + } else { + this.parse_expr_lit() + } } else { this.parse_expr_lit() } @@ -1550,10 +1557,7 @@ impl<'a> Parser<'a> { self.sess.emit_err(errors::MacroInvocationWithQualifiedPath(path.span)); } let lo = path.span; - let mac = P(MacCall { - path, - args: self.parse_delim_args()?, - }); + let mac = P(MacCall { path, args: self.parse_delim_args()? }); (lo.to(self.prev_token.span), ExprKind::MacCall(mac)) } else if self.check(&token::OpenDelim(Delimiter::Brace)) && let Some(expr) = self.maybe_parse_struct_expr(&qself, &path) @@ -1592,7 +1596,7 @@ impl<'a> Parser<'a> { } else if !ate_colon && self.may_recover() && (matches!(self.token.kind, token::CloseDelim(_) | token::Comma) - || self.token.is_op()) + || self.token.is_punct()) { let (lit, _) = self.recover_unclosed_char(label_.ident, Parser::mk_token_lit_char, |self_| { @@ -1771,7 +1775,9 @@ impl<'a> Parser<'a> { fn parse_expr_break(&mut self) -> PResult<'a, P<Expr>> { let lo = self.prev_token.span; let mut label = self.eat_label(); - let kind = if self.token == token::Colon && let Some(label) = label.take() { + let kind = if self.token == token::Colon + && let Some(label) = label.take() + { // The value expression can be a labeled loop, see issue #86948, e.g.: // `loop { break 'label: loop { break 'label 42; }; }` let lexpr = self.parse_expr_labeled(label, true)?; @@ -1848,7 +1854,7 @@ impl<'a> Parser<'a> { let lo = self.prev_token.span; let kind = ExprKind::Yield(self.parse_expr_opt()?); let span = lo.to(self.prev_token.span); - self.sess.gated_spans.gate(sym::generators, span); + self.sess.gated_spans.gate(sym::yield_expr, span); let expr = self.mk_expr(span, kind); self.maybe_recover_from_bad_qpath(expr) } @@ -2209,6 +2215,7 @@ impl<'a> Parser<'a> { fn parse_expr_closure(&mut self) -> PResult<'a, P<Expr>> { let lo = self.token.span; + let before = self.prev_token.clone(); let binder = if self.check_keyword(kw::For) { let lo = self.token.span; let lifetime_defs = self.parse_late_bound_lifetime_defs()?; @@ -2239,7 +2246,12 @@ impl<'a> Parser<'a> { FnRetTy::Default(_) => { let restrictions = self.restrictions - Restrictions::STMT_EXPR - Restrictions::ALLOW_LET; - self.parse_expr_res(restrictions, None)? + let prev = self.prev_token.clone(); + let token = self.token.clone(); + match self.parse_expr_res(restrictions, None) { + Ok(expr) => expr, + Err(err) => self.recover_closure_body(err, before, prev, token, lo, decl_hi)?, + } } _ => { // If an explicit return type is given, require a block to appear (RFC 968). @@ -2371,16 +2383,18 @@ impl<'a> Parser<'a> { let mut recover_block_from_condition = |this: &mut Self| { let block = match &mut cond.kind { ExprKind::Binary(Spanned { span: binop_span, .. }, _, right) - if let ExprKind::Block(_, None) = right.kind => { - self.sess.emit_err(errors::IfExpressionMissingThenBlock { - if_span: lo, - missing_then_block_sub: - errors::IfExpressionMissingThenBlockSub::UnfinishedCondition(cond_span.shrink_to_lo().to(*binop_span)), - let_else_sub: None, - - }); - std::mem::replace(right, this.mk_expr_err(binop_span.shrink_to_hi())) - }, + if let ExprKind::Block(_, None) = right.kind => + { + self.sess.emit_err(errors::IfExpressionMissingThenBlock { + if_span: lo, + missing_then_block_sub: + errors::IfExpressionMissingThenBlockSub::UnfinishedCondition( + cond_span.shrink_to_lo().to(*binop_span), + ), + let_else_sub: None, + }); + std::mem::replace(right, this.mk_expr_err(binop_span.shrink_to_hi())) + } ExprKind::Block(_, None) => { self.sess.emit_err(errors::IfExpressionMissingCondition { if_span: lo.shrink_to_hi(), @@ -2459,10 +2473,16 @@ impl<'a> Parser<'a> { /// Parses a `let $pat = $expr` pseudo-expression. fn parse_expr_let(&mut self, restrictions: Restrictions) -> PResult<'a, P<Expr>> { let is_recovered = if !restrictions.contains(Restrictions::ALLOW_LET) { - Some(self.sess.emit_err(errors::ExpectedExpressionFoundLet { + let err = errors::ExpectedExpressionFoundLet { span: self.token.span, reason: ForbiddenLetReason::OtherForbidden, - })) + }; + if self.prev_token.kind == token::BinOp(token::Or) { + // This was part of a closure, the that part of the parser recover. + return Err(err.into_diagnostic(&self.sess.span_diagnostic)); + } else { + Some(self.sess.emit_err(err)) + } } else { None }; @@ -2557,13 +2577,16 @@ impl<'a> Parser<'a> { } fn error_on_extra_if(&mut self, cond: &P<Expr>) -> PResult<'a, ()> { - if let ExprKind::Binary(Spanned { span: binop_span, node: binop}, _, right) = &cond.kind && - let BinOpKind::And = binop && - let ExprKind::If(cond, ..) = &right.kind { - Err(self.sess.create_err(errors::UnexpectedIfWithIf(binop_span.shrink_to_hi().to(cond.span.shrink_to_lo())))) - } else { - Ok(()) - } + if let ExprKind::Binary(Spanned { span: binop_span, node: binop }, _, right) = &cond.kind + && let BinOpKind::And = binop + && let ExprKind::If(cond, ..) = &right.kind + { + Err(self.sess.create_err(errors::UnexpectedIfWithIf( + binop_span.shrink_to_hi().to(cond.span.shrink_to_lo()), + ))) + } else { + Ok(()) + } } /// Parses `for <src_pat> in <src_expr> <src_loop_block>` (`for` token already eaten). @@ -2834,7 +2857,7 @@ impl<'a> Parser<'a> { )?; let guard = if this.eat_keyword(kw::If) { let if_span = this.prev_token.span; - let mut cond = this.parse_expr_res(Restrictions::ALLOW_LET, None)?; + let mut cond = this.parse_match_guard_condition()?; CondChecker { parser: this, forbid_let_reason: None }.visit_expr(&mut cond); @@ -2860,9 +2883,9 @@ impl<'a> Parser<'a> { { err.span_suggestion( this.token.span, - "try using a fat arrow here", + "use a fat arrow to start a match arm", "=>", - Applicability::MaybeIncorrect, + Applicability::MachineApplicable, ); err.emit(); this.bump(); @@ -2911,9 +2934,9 @@ impl<'a> Parser<'a> { .or_else(|mut err| { if this.token == token::FatArrow { if let Ok(expr_lines) = sm.span_to_lines(expr.span) - && let Ok(arm_start_lines) = sm.span_to_lines(arm_start_span) - && arm_start_lines.lines[0].end_col == expr_lines.lines[0].end_col - && expr_lines.lines.len() == 2 + && let Ok(arm_start_lines) = sm.span_to_lines(arm_start_span) + && arm_start_lines.lines[0].end_col == expr_lines.lines[0].end_col + && expr_lines.lines.len() == 2 { // We check whether there's any trailing code in the parse span, // if there isn't, we very likely have the following: @@ -2979,6 +3002,33 @@ impl<'a> Parser<'a> { }) } + fn parse_match_guard_condition(&mut self) -> PResult<'a, P<Expr>> { + self.parse_expr_res(Restrictions::ALLOW_LET | Restrictions::IN_IF_GUARD, None).map_err( + |mut err| { + if self.prev_token == token::OpenDelim(Delimiter::Brace) { + let sugg_sp = self.prev_token.span.shrink_to_lo(); + // Consume everything within the braces, let's avoid further parse + // errors. + self.recover_stmt_(SemiColonMode::Ignore, BlockMode::Ignore); + let msg = "you might have meant to start a match arm after the match guard"; + if self.eat(&token::CloseDelim(Delimiter::Brace)) { + let applicability = if self.token.kind != token::FatArrow { + // We have high confidence that we indeed didn't have a struct + // literal in the match guard, but rather we had some operation + // that ended in a path, immediately followed by a block that was + // meant to be the match arm. + Applicability::MachineApplicable + } else { + Applicability::MaybeIncorrect + }; + err.span_suggestion_verbose(sugg_sp, msg, "=> ".to_string(), applicability); + } + } + err + }, + ) + } + pub(crate) fn is_builtin(&self) -> bool { self.token.is_keyword(kw::Builtin) && self.look_ahead(1, |t| *t == token::Pound) } @@ -3015,18 +3065,24 @@ impl<'a> Parser<'a> { && self.token.uninterpolated_span().at_least_rust_2018() } - /// Parses an `async move? {...}` expression. - fn parse_async_block(&mut self) -> PResult<'a, P<Expr>> { + /// Parses an `async move? {...}` or `gen move? {...}` expression. + fn parse_gen_block(&mut self) -> PResult<'a, P<Expr>> { let lo = self.token.span; - self.expect_keyword(kw::Async)?; + let kind = if self.eat_keyword(kw::Async) { + GenBlockKind::Async + } else { + assert!(self.eat_keyword(kw::Gen)); + self.sess.gated_spans.gate(sym::gen_blocks, lo.to(self.token.span)); + GenBlockKind::Gen + }; let capture_clause = self.parse_capture_clause()?; let (attrs, body) = self.parse_inner_attrs_and_block()?; - let kind = ExprKind::Async(capture_clause, body); + let kind = ExprKind::Gen(capture_clause, body, kind); Ok(self.mk_expr_with_attrs(lo.to(self.prev_token.span), kind, attrs)) } - fn is_async_block(&self) -> bool { - self.token.is_keyword(kw::Async) + fn is_gen_block(&self, kw: Symbol) -> bool { + self.token.is_keyword(kw) && (( // `async move {` self.is_keyword_ahead(1, &[kw::Move]) @@ -3049,9 +3105,10 @@ impl<'a> Parser<'a> { || self.look_ahead(2, |t| t == &token::Colon) && ( // `{ ident: token, ` cannot start a block. - self.look_ahead(4, |t| t == &token::Comma) || - // `{ ident: ` cannot start a block unless it's a type ascription `ident: Type`. - self.look_ahead(3, |t| !t.can_begin_type()) + self.look_ahead(4, |t| t == &token::Comma) + // `{ ident: ` cannot start a block unless it's a type ascription + // `ident: Type`. + || self.look_ahead(3, |t| !t.can_begin_type()) ) ) } @@ -3091,6 +3148,7 @@ impl<'a> Parser<'a> { let mut fields = ThinVec::new(); let mut base = ast::StructRest::None; let mut recover_async = false; + let in_if_guard = self.restrictions.contains(Restrictions::IN_IF_GUARD); let mut async_block_err = |e: &mut Diagnostic, span: Span| { recover_async = true; @@ -3128,6 +3186,26 @@ impl<'a> Parser<'a> { e.span_label(pth.span, "while parsing this struct"); } + if let Some((ident, _)) = self.token.ident() + && !self.token.is_reserved_ident() + && self.look_ahead(1, |t| { + AssocOp::from_token(&t).is_some() + || matches!(t.kind, token::OpenDelim(_)) + || t.kind == token::Dot + }) + { + // Looks like they tried to write a shorthand, complex expression. + e.span_suggestion_verbose( + self.token.span.shrink_to_lo(), + "try naming a field", + &format!("{ident}: ",), + Applicability::MaybeIncorrect, + ); + } + if in_if_guard && close_delim == Delimiter::Brace { + return Err(e); + } + if !recover { return Err(e); } @@ -3173,19 +3251,6 @@ impl<'a> Parser<'a> { ",", Applicability::MachineApplicable, ); - } else if is_shorthand - && (AssocOp::from_token(&self.token).is_some() - || matches!(&self.token.kind, token::OpenDelim(_)) - || self.token.kind == token::Dot) - { - // Looks like they tried to write a shorthand, complex expression. - let ident = parsed_field.expect("is_shorthand implies Some").ident; - e.span_suggestion( - ident.span.shrink_to_lo(), - "try naming a field", - &format!("{ident}: "), - Applicability::HasPlaceholders, - ); } } if !recover { @@ -3288,6 +3353,24 @@ impl<'a> Parser<'a> { // Check if a colon exists one ahead. This means we're parsing a fieldname. let is_shorthand = !this.look_ahead(1, |t| t == &token::Colon || t == &token::Eq); + // Proactively check whether parsing the field will be incorrect. + let is_wrong = this.token.is_ident() + && !this.token.is_reserved_ident() + && !this.look_ahead(1, |t| { + t == &token::Colon + || t == &token::Eq + || t == &token::Comma + || t == &token::CloseDelim(Delimiter::Brace) + || t == &token::CloseDelim(Delimiter::Parenthesis) + }); + if is_wrong { + return Err(errors::ExpectedStructField { + span: this.look_ahead(1, |t| t.span), + ident_span: this.token.span, + token: this.look_ahead(1, |t| t.clone()), + } + .into_diagnostic(&self.sess.span_diagnostic)); + } let (ident, expr) = if is_shorthand { // Mimic `x: x` for the `x` field shorthand. let ident = this.parse_ident_common(false)?; @@ -3508,8 +3591,7 @@ impl MutVisitor for CondChecker<'_> { noop_visit_expr(e, self); self.forbid_let_reason = forbid_let_reason; } - ExprKind::Cast(ref mut op, _) - | ExprKind::Type(ref mut op, _) => { + ExprKind::Cast(ref mut op, _) | ExprKind::Type(ref mut op, _) => { let forbid_let_reason = self.forbid_let_reason; self.forbid_let_reason = Some(OtherForbidden); self.visit_expr(op); @@ -3526,7 +3608,7 @@ impl MutVisitor for CondChecker<'_> { | ExprKind::Match(_, _) | ExprKind::Closure(_) | ExprKind::Block(_, _) - | ExprKind::Async(_, _) + | ExprKind::Gen(_, _, _) | ExprKind::TryBlock(_) | ExprKind::Underscore | ExprKind::Path(_, _) |