bf8ce32558
By replacing them with `{Open,Close}{Param,Brace,Bracket,Invisible}`.
PR #137902 made `ast::TokenKind` more like `lexer::TokenKind` by
replacing the compound `BinOp{,Eq}(BinOpToken)` variants with fieldless
variants `Plus`, `Minus`, `Star`, etc. This commit does a similar thing
with delimiters. It also makes `ast::TokenKind` more similar to
`parser::TokenType`.
This requires a few new methods:
- `TokenKind::is_{,open_,close_}delim()` replace various kinds of
pattern matches.
- `Delimiter::as_{open,close}_token_kind` are used to convert
`Delimiter` values to `TokenKind`.
Despite these additions, it's a net reduction in lines of code. This is
because e.g. `token::OpenParen` is so much shorter than
`token::OpenDelim(Delimiter::Parenthesis)` that many multi-line forms
reduce to single line forms. And many places where the number of lines
doesn't change are still easier to read, just because the names are
shorter, e.g.:
```
- } else if self.token != token::CloseDelim(Delimiter::Brace) {
+ } else if self.token != token::CloseBrace {
```
1064 lines
46 KiB
Rust
1064 lines
46 KiB
Rust
use std::borrow::Cow;
|
||
use std::mem;
|
||
use std::ops::Bound;
|
||
|
||
use ast::Label;
|
||
use rustc_ast as ast;
|
||
use rustc_ast::ptr::P;
|
||
use rustc_ast::token::{self, Delimiter, InvisibleOrigin, MetaVarKind, TokenKind};
|
||
use rustc_ast::util::classify::{self, TrailingBrace};
|
||
use rustc_ast::{
|
||
AttrStyle, AttrVec, Block, BlockCheckMode, DUMMY_NODE_ID, Expr, ExprKind, HasAttrs, Local,
|
||
LocalKind, MacCall, MacCallStmt, MacStmtStyle, Recovered, Stmt, StmtKind,
|
||
};
|
||
use rustc_errors::{Applicability, Diag, PResult};
|
||
use rustc_span::{BytePos, ErrorGuaranteed, Ident, Span, kw, sym};
|
||
use thin_vec::{ThinVec, thin_vec};
|
||
|
||
use super::attr::InnerAttrForbiddenReason;
|
||
use super::diagnostics::AttemptLocalParseRecovery;
|
||
use super::pat::{PatternLocation, RecoverComma};
|
||
use super::path::PathStyle;
|
||
use super::{
|
||
AttrWrapper, BlockMode, FnParseMode, ForceCollect, Parser, Restrictions, SemiColonMode,
|
||
Trailing, UsePreAttrPos,
|
||
};
|
||
use crate::errors::{self, MalformedLoopLabel};
|
||
use crate::exp;
|
||
|
||
impl<'a> Parser<'a> {
|
||
/// Parses a statement. This stops just before trailing semicolons on everything but items.
|
||
/// e.g., a `StmtKind::Semi` parses to a `StmtKind::Expr`, leaving the trailing `;` unconsumed.
|
||
///
|
||
/// If `force_collect` is [`ForceCollect::Yes`], forces collection of tokens regardless of
|
||
/// whether or not we have attributes.
|
||
// Public for rustfmt usage.
|
||
pub fn parse_stmt(&mut self, force_collect: ForceCollect) -> PResult<'a, Option<Stmt>> {
|
||
Ok(self.parse_stmt_without_recovery(false, force_collect, false).unwrap_or_else(|e| {
|
||
e.emit();
|
||
self.recover_stmt_(SemiColonMode::Break, BlockMode::Ignore);
|
||
None
|
||
}))
|
||
}
|
||
|
||
/// If `force_collect` is [`ForceCollect::Yes`], forces collection of tokens regardless of
|
||
/// whether or not we have attributes. If `force_full_expr` is true, parses the stmt without
|
||
/// using `Restriction::STMT_EXPR`. Public for `cfg_eval` macro expansion.
|
||
pub fn parse_stmt_without_recovery(
|
||
&mut self,
|
||
capture_semi: bool,
|
||
force_collect: ForceCollect,
|
||
force_full_expr: bool,
|
||
) -> PResult<'a, Option<Stmt>> {
|
||
let pre_attr_pos = self.collect_pos();
|
||
let attrs = self.parse_outer_attributes()?;
|
||
let lo = self.token.span;
|
||
|
||
if let Some(stmt) = self.eat_metavar_seq(MetaVarKind::Stmt, |this| {
|
||
this.parse_stmt_without_recovery(false, ForceCollect::Yes, false)
|
||
}) {
|
||
let mut stmt = stmt.expect("an actual statement");
|
||
stmt.visit_attrs(|stmt_attrs| {
|
||
attrs.prepend_to_nt_inner(stmt_attrs);
|
||
});
|
||
return Ok(Some(stmt));
|
||
}
|
||
|
||
if self.token.is_keyword(kw::Mut) && self.is_keyword_ahead(1, &[kw::Let]) {
|
||
self.bump();
|
||
let mut_let_span = lo.to(self.token.span);
|
||
self.dcx().emit_err(errors::InvalidVariableDeclaration {
|
||
span: mut_let_span,
|
||
sub: errors::InvalidVariableDeclarationSub::SwitchMutLetOrder(mut_let_span),
|
||
});
|
||
}
|
||
|
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let stmt = if self.token.is_keyword(kw::Super) && self.is_keyword_ahead(1, &[kw::Let]) {
|
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self.collect_tokens(None, attrs, force_collect, |this, attrs| {
|
||
let super_span = this.token.span;
|
||
this.expect_keyword(exp!(Super))?;
|
||
this.expect_keyword(exp!(Let))?;
|
||
this.psess.gated_spans.gate(sym::super_let, super_span);
|
||
let local = this.parse_local(Some(super_span), attrs)?;
|
||
let trailing = Trailing::from(capture_semi && this.token == token::Semi);
|
||
Ok((
|
||
this.mk_stmt(lo.to(this.prev_token.span), StmtKind::Let(local)),
|
||
trailing,
|
||
UsePreAttrPos::No,
|
||
))
|
||
})?
|
||
} else if self.token.is_keyword(kw::Let) {
|
||
self.collect_tokens(None, attrs, force_collect, |this, attrs| {
|
||
this.expect_keyword(exp!(Let))?;
|
||
let local = this.parse_local(None, attrs)?;
|
||
let trailing = Trailing::from(capture_semi && this.token == token::Semi);
|
||
Ok((
|
||
this.mk_stmt(lo.to(this.prev_token.span), StmtKind::Let(local)),
|
||
trailing,
|
||
UsePreAttrPos::No,
|
||
))
|
||
})?
|
||
} else if self.is_kw_followed_by_ident(kw::Mut) && self.may_recover() {
|
||
self.recover_stmt_local_after_let(
|
||
lo,
|
||
attrs,
|
||
errors::InvalidVariableDeclarationSub::MissingLet,
|
||
force_collect,
|
||
)?
|
||
} else if self.is_kw_followed_by_ident(kw::Auto) && self.may_recover() {
|
||
self.bump(); // `auto`
|
||
self.recover_stmt_local_after_let(
|
||
lo,
|
||
attrs,
|
||
errors::InvalidVariableDeclarationSub::UseLetNotAuto,
|
||
force_collect,
|
||
)?
|
||
} else if self.is_kw_followed_by_ident(sym::var) && self.may_recover() {
|
||
self.bump(); // `var`
|
||
self.recover_stmt_local_after_let(
|
||
lo,
|
||
attrs,
|
||
errors::InvalidVariableDeclarationSub::UseLetNotVar,
|
||
force_collect,
|
||
)?
|
||
} else if self.check_path()
|
||
&& !self.token.is_qpath_start()
|
||
&& !self.is_path_start_item()
|
||
&& !self.is_builtin()
|
||
{
|
||
// We have avoided contextual keywords like `union`, items with `crate` visibility,
|
||
// or `auto trait` items. We aim to parse an arbitrary path `a::b` but not something
|
||
// that starts like a path (1 token), but it fact not a path.
|
||
// Also, we avoid stealing syntax from `parse_item_`.
|
||
//
|
||
// `UsePreAttrPos::Yes` here means the attribute belongs unconditionally to the
|
||
// expression, not the statement. (But the statement attributes/tokens are obtained
|
||
// from the expression anyway, because `Stmt` delegates `HasAttrs`/`HasTokens` to
|
||
// the things within `StmtKind`.)
|
||
let stmt = self.collect_tokens(
|
||
Some(pre_attr_pos),
|
||
AttrWrapper::empty(),
|
||
force_collect,
|
||
|this, _empty_attrs| {
|
||
Ok((this.parse_stmt_path_start(lo, attrs)?, Trailing::No, UsePreAttrPos::Yes))
|
||
},
|
||
);
|
||
match stmt {
|
||
Ok(stmt) => stmt,
|
||
Err(mut err) => {
|
||
self.suggest_add_missing_let_for_stmt(&mut err);
|
||
return Err(err);
|
||
}
|
||
}
|
||
} else if let Some(item) = self.parse_item_common(
|
||
attrs.clone(), // FIXME: unwanted clone of attrs
|
||
false,
|
||
true,
|
||
FnParseMode { req_name: |_| true, req_body: true },
|
||
force_collect,
|
||
)? {
|
||
self.mk_stmt(lo.to(item.span), StmtKind::Item(P(item)))
|
||
} else if self.eat(exp!(Semi)) {
|
||
// Do not attempt to parse an expression if we're done here.
|
||
self.error_outer_attrs(attrs);
|
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self.mk_stmt(lo, StmtKind::Empty)
|
||
} else if self.token != token::CloseBrace {
|
||
// Remainder are line-expr stmts. This is similar to the `parse_stmt_path_start` case
|
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// above.
|
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let restrictions =
|
||
if force_full_expr { Restrictions::empty() } else { Restrictions::STMT_EXPR };
|
||
let e = self.collect_tokens(
|
||
Some(pre_attr_pos),
|
||
AttrWrapper::empty(),
|
||
force_collect,
|
||
|this, _empty_attrs| {
|
||
let (expr, _) = this.parse_expr_res(restrictions, attrs)?;
|
||
Ok((expr, Trailing::No, UsePreAttrPos::Yes))
|
||
},
|
||
)?;
|
||
if matches!(e.kind, ExprKind::Assign(..)) && self.eat_keyword(exp!(Else)) {
|
||
let bl = self.parse_block()?;
|
||
// Destructuring assignment ... else.
|
||
// This is not allowed, but point it out in a nice way.
|
||
self.dcx().emit_err(errors::AssignmentElseNotAllowed { span: e.span.to(bl.span) });
|
||
}
|
||
self.mk_stmt(lo.to(e.span), StmtKind::Expr(e))
|
||
} else {
|
||
self.error_outer_attrs(attrs);
|
||
return Ok(None);
|
||
};
|
||
|
||
self.maybe_augment_stashed_expr_in_pats_with_suggestions(&stmt);
|
||
Ok(Some(stmt))
|
||
}
|
||
|
||
fn parse_stmt_path_start(&mut self, lo: Span, attrs: AttrWrapper) -> PResult<'a, Stmt> {
|
||
let stmt = self.collect_tokens(None, attrs, ForceCollect::No, |this, attrs| {
|
||
let path = this.parse_path(PathStyle::Expr)?;
|
||
|
||
if this.eat(exp!(Bang)) {
|
||
let stmt_mac = this.parse_stmt_mac(lo, attrs, path)?;
|
||
return Ok((
|
||
stmt_mac,
|
||
Trailing::from(this.token == token::Semi),
|
||
UsePreAttrPos::No,
|
||
));
|
||
}
|
||
|
||
let expr = if this.eat(exp!(OpenBrace)) {
|
||
this.parse_expr_struct(None, path, true)?
|
||
} else {
|
||
let hi = this.prev_token.span;
|
||
this.mk_expr(lo.to(hi), ExprKind::Path(None, path))
|
||
};
|
||
|
||
let expr = this.with_res(Restrictions::STMT_EXPR, |this| {
|
||
this.parse_expr_dot_or_call_with(attrs, expr, lo)
|
||
})?;
|
||
// `DUMMY_SP` will get overwritten later in this function
|
||
Ok((
|
||
this.mk_stmt(rustc_span::DUMMY_SP, StmtKind::Expr(expr)),
|
||
Trailing::No,
|
||
UsePreAttrPos::No,
|
||
))
|
||
})?;
|
||
|
||
if let StmtKind::Expr(expr) = stmt.kind {
|
||
// Perform this outside of the `collect_tokens` closure, since our
|
||
// outer attributes do not apply to this part of the expression.
|
||
let (expr, _) = self.with_res(Restrictions::STMT_EXPR, |this| {
|
||
this.parse_expr_assoc_rest_with(Bound::Unbounded, true, expr)
|
||
})?;
|
||
Ok(self.mk_stmt(lo.to(self.prev_token.span), StmtKind::Expr(expr)))
|
||
} else {
|
||
Ok(stmt)
|
||
}
|
||
}
|
||
|
||
/// Parses a statement macro `mac!(args)` provided a `path` representing `mac`.
|
||
/// At this point, the `!` token after the path has already been eaten.
|
||
fn parse_stmt_mac(&mut self, lo: Span, attrs: AttrVec, path: ast::Path) -> PResult<'a, Stmt> {
|
||
let args = self.parse_delim_args()?;
|
||
let hi = self.prev_token.span;
|
||
|
||
let style = match args.delim {
|
||
Delimiter::Brace => MacStmtStyle::Braces,
|
||
_ => MacStmtStyle::NoBraces,
|
||
};
|
||
|
||
let mac = P(MacCall { path, args });
|
||
|
||
let kind = if (style == MacStmtStyle::Braces
|
||
&& !matches!(self.token.kind, token::Dot | token::Question))
|
||
|| matches!(
|
||
self.token.kind,
|
||
token::Semi
|
||
| token::Eof
|
||
| token::CloseInvisible(InvisibleOrigin::MetaVar(MetaVarKind::Stmt))
|
||
) {
|
||
StmtKind::MacCall(P(MacCallStmt { mac, style, attrs, tokens: None }))
|
||
} else {
|
||
// Since none of the above applied, this is an expression statement macro.
|
||
let e = self.mk_expr(lo.to(hi), ExprKind::MacCall(mac));
|
||
let e = self.maybe_recover_from_bad_qpath(e)?;
|
||
let e = self.parse_expr_dot_or_call_with(attrs, e, lo)?;
|
||
let (e, _) = self.parse_expr_assoc_rest_with(Bound::Unbounded, false, e)?;
|
||
StmtKind::Expr(e)
|
||
};
|
||
Ok(self.mk_stmt(lo.to(hi), kind))
|
||
}
|
||
|
||
/// Error on outer attributes in this context.
|
||
/// Also error if the previous token was a doc comment.
|
||
fn error_outer_attrs(&self, attrs: AttrWrapper) {
|
||
if !attrs.is_empty()
|
||
&& let attrs @ [.., last] = &*attrs.take_for_recovery(self.psess)
|
||
{
|
||
if last.is_doc_comment() {
|
||
self.dcx().emit_err(errors::DocCommentDoesNotDocumentAnything {
|
||
span: last.span,
|
||
missing_comma: None,
|
||
});
|
||
} else if attrs.iter().any(|a| a.style == AttrStyle::Outer) {
|
||
self.dcx().emit_err(errors::ExpectedStatementAfterOuterAttr { span: last.span });
|
||
}
|
||
}
|
||
}
|
||
|
||
fn recover_stmt_local_after_let(
|
||
&mut self,
|
||
lo: Span,
|
||
attrs: AttrWrapper,
|
||
subdiagnostic: fn(Span) -> errors::InvalidVariableDeclarationSub,
|
||
force_collect: ForceCollect,
|
||
) -> PResult<'a, Stmt> {
|
||
let stmt = self.collect_tokens(None, attrs, force_collect, |this, attrs| {
|
||
let local = this.parse_local(None, attrs)?;
|
||
// FIXME - maybe capture semicolon in recovery?
|
||
Ok((
|
||
this.mk_stmt(lo.to(this.prev_token.span), StmtKind::Let(local)),
|
||
Trailing::No,
|
||
UsePreAttrPos::No,
|
||
))
|
||
})?;
|
||
self.dcx()
|
||
.emit_err(errors::InvalidVariableDeclaration { span: lo, sub: subdiagnostic(lo) });
|
||
Ok(stmt)
|
||
}
|
||
|
||
/// Parses a local variable declaration.
|
||
fn parse_local(&mut self, super_: Option<Span>, attrs: AttrVec) -> PResult<'a, P<Local>> {
|
||
let lo = super_.unwrap_or(self.prev_token.span);
|
||
|
||
if self.token.is_keyword(kw::Const) && self.look_ahead(1, |t| t.is_ident()) {
|
||
self.dcx().emit_err(errors::ConstLetMutuallyExclusive { span: lo.to(self.token.span) });
|
||
self.bump();
|
||
}
|
||
|
||
let (pat, colon) =
|
||
self.parse_pat_before_ty(None, RecoverComma::Yes, PatternLocation::LetBinding)?;
|
||
|
||
let (err, ty, colon_sp) = if colon {
|
||
// Save the state of the parser before parsing type normally, in case there is a `:`
|
||
// instead of an `=` typo.
|
||
let parser_snapshot_before_type = self.clone();
|
||
let colon_sp = self.prev_token.span;
|
||
match self.parse_ty() {
|
||
Ok(ty) => (None, Some(ty), Some(colon_sp)),
|
||
Err(mut err) => {
|
||
err.span_label(
|
||
colon_sp,
|
||
format!(
|
||
"while parsing the type for {}",
|
||
pat.descr()
|
||
.map_or_else(|| "the binding".to_string(), |n| format!("`{n}`"))
|
||
),
|
||
);
|
||
// we use noexpect here because we don't actually expect Eq to be here
|
||
// but we are still checking for it in order to be able to handle it if
|
||
// it is there
|
||
let err = if self.check_noexpect(&token::Eq) {
|
||
err.emit();
|
||
None
|
||
} else {
|
||
// Rewind to before attempting to parse the type and continue parsing.
|
||
let parser_snapshot_after_type =
|
||
mem::replace(self, parser_snapshot_before_type);
|
||
Some((parser_snapshot_after_type, colon_sp, err))
|
||
};
|
||
(err, None, Some(colon_sp))
|
||
}
|
||
}
|
||
} else {
|
||
(None, None, None)
|
||
};
|
||
let init = match (self.parse_initializer(err.is_some()), err) {
|
||
(Ok(init), None) => {
|
||
// init parsed, ty parsed
|
||
init
|
||
}
|
||
(Ok(init), Some((_, colon_sp, mut err))) => {
|
||
// init parsed, ty error
|
||
// Could parse the type as if it were the initializer, it is likely there was a
|
||
// typo in the code: `:` instead of `=`. Add suggestion and emit the error.
|
||
err.span_suggestion_short(
|
||
colon_sp,
|
||
"use `=` if you meant to assign",
|
||
" =",
|
||
Applicability::MachineApplicable,
|
||
);
|
||
err.emit();
|
||
// As this was parsed successfully, continue as if the code has been fixed for the
|
||
// rest of the file. It will still fail due to the emitted error, but we avoid
|
||
// extra noise.
|
||
init
|
||
}
|
||
(Err(init_err), Some((snapshot, _, ty_err))) => {
|
||
// init error, ty error
|
||
init_err.cancel();
|
||
// Couldn't parse the type nor the initializer, only raise the type error and
|
||
// return to the parser state before parsing the type as the initializer.
|
||
// let x: <parse_error>;
|
||
*self = snapshot;
|
||
return Err(ty_err);
|
||
}
|
||
(Err(err), None) => {
|
||
// init error, ty parsed
|
||
// Couldn't parse the initializer and we're not attempting to recover a failed
|
||
// parse of the type, return the error.
|
||
return Err(err);
|
||
}
|
||
};
|
||
let kind = match init {
|
||
None => LocalKind::Decl,
|
||
Some(init) => {
|
||
if self.eat_keyword(exp!(Else)) {
|
||
if self.token.is_keyword(kw::If) {
|
||
// `let...else if`. Emit the same error that `parse_block()` would,
|
||
// but explicitly point out that this pattern is not allowed.
|
||
let msg = "conditional `else if` is not supported for `let...else`";
|
||
return Err(self.error_block_no_opening_brace_msg(Cow::from(msg)));
|
||
}
|
||
let els = self.parse_block()?;
|
||
self.check_let_else_init_bool_expr(&init);
|
||
self.check_let_else_init_trailing_brace(&init);
|
||
LocalKind::InitElse(init, els)
|
||
} else {
|
||
LocalKind::Init(init)
|
||
}
|
||
}
|
||
};
|
||
let hi = if self.token == token::Semi { self.token.span } else { self.prev_token.span };
|
||
Ok(P(ast::Local {
|
||
super_,
|
||
ty,
|
||
pat,
|
||
kind,
|
||
id: DUMMY_NODE_ID,
|
||
span: lo.to(hi),
|
||
colon_sp,
|
||
attrs,
|
||
tokens: None,
|
||
}))
|
||
}
|
||
|
||
fn check_let_else_init_bool_expr(&self, init: &ast::Expr) {
|
||
if let ast::ExprKind::Binary(op, ..) = init.kind {
|
||
if op.node.is_lazy() {
|
||
self.dcx().emit_err(errors::InvalidExpressionInLetElse {
|
||
span: init.span,
|
||
operator: op.node.as_str(),
|
||
sugg: errors::WrapInParentheses::Expression {
|
||
left: init.span.shrink_to_lo(),
|
||
right: init.span.shrink_to_hi(),
|
||
},
|
||
});
|
||
}
|
||
}
|
||
}
|
||
|
||
fn check_let_else_init_trailing_brace(&self, init: &ast::Expr) {
|
||
if let Some(trailing) = classify::expr_trailing_brace(init) {
|
||
let (span, sugg) = match trailing {
|
||
TrailingBrace::MacCall(mac) => (
|
||
mac.span(),
|
||
errors::WrapInParentheses::MacroArgs {
|
||
left: mac.args.dspan.open,
|
||
right: mac.args.dspan.close,
|
||
},
|
||
),
|
||
TrailingBrace::Expr(expr) => (
|
||
expr.span,
|
||
errors::WrapInParentheses::Expression {
|
||
left: expr.span.shrink_to_lo(),
|
||
right: expr.span.shrink_to_hi(),
|
||
},
|
||
),
|
||
};
|
||
self.dcx().emit_err(errors::InvalidCurlyInLetElse {
|
||
span: span.with_lo(span.hi() - BytePos(1)),
|
||
sugg,
|
||
});
|
||
}
|
||
}
|
||
|
||
/// Parses the RHS of a local variable declaration (e.g., `= 14;`).
|
||
fn parse_initializer(&mut self, eq_optional: bool) -> PResult<'a, Option<P<Expr>>> {
|
||
let eq_consumed = match self.token.kind {
|
||
token::PlusEq
|
||
| token::MinusEq
|
||
| token::StarEq
|
||
| token::SlashEq
|
||
| token::PercentEq
|
||
| token::CaretEq
|
||
| token::AndEq
|
||
| token::OrEq
|
||
| token::ShlEq
|
||
| token::ShrEq => {
|
||
// Recover `let x <op>= 1` as `let x = 1` We must not use `+ BytePos(1)` here
|
||
// because `<op>` can be a multi-byte lookalike that was recovered, e.g. `➖=` (the
|
||
// `➖` is a U+2796 Heavy Minus Sign Unicode Character) that was recovered as a
|
||
// `-=`.
|
||
let extra_op_span = self.psess.source_map().start_point(self.token.span);
|
||
self.dcx().emit_err(errors::CompoundAssignmentExpressionInLet {
|
||
span: self.token.span,
|
||
suggestion: extra_op_span,
|
||
});
|
||
self.bump();
|
||
true
|
||
}
|
||
_ => self.eat(exp!(Eq)),
|
||
};
|
||
|
||
Ok(if eq_consumed || eq_optional { Some(self.parse_expr()?) } else { None })
|
||
}
|
||
|
||
/// Parses a block. No inner attributes are allowed.
|
||
pub fn parse_block(&mut self) -> PResult<'a, P<Block>> {
|
||
let (attrs, block) = self.parse_inner_attrs_and_block(None)?;
|
||
if let [.., last] = &*attrs {
|
||
let suggest_to_outer = match &last.kind {
|
||
ast::AttrKind::Normal(attr) => attr.item.is_valid_for_outer_style(),
|
||
_ => false,
|
||
};
|
||
self.error_on_forbidden_inner_attr(
|
||
last.span,
|
||
super::attr::InnerAttrPolicy::Forbidden(Some(
|
||
InnerAttrForbiddenReason::InCodeBlock,
|
||
)),
|
||
suggest_to_outer,
|
||
);
|
||
}
|
||
Ok(block)
|
||
}
|
||
|
||
fn error_block_no_opening_brace_msg(&mut self, msg: Cow<'static, str>) -> Diag<'a> {
|
||
let prev = self.prev_token.span;
|
||
let sp = self.token.span;
|
||
let mut e = self.dcx().struct_span_err(sp, msg);
|
||
self.label_expected_raw_ref(&mut e);
|
||
|
||
let do_not_suggest_help = self.token.is_keyword(kw::In)
|
||
|| self.token == token::Colon
|
||
|| self.prev_token.is_keyword(kw::Raw);
|
||
|
||
// Check to see if the user has written something like
|
||
//
|
||
// if (cond)
|
||
// bar;
|
||
//
|
||
// which is valid in other languages, but not Rust.
|
||
match self.parse_stmt_without_recovery(false, ForceCollect::No, false) {
|
||
// If the next token is an open brace, e.g., we have:
|
||
//
|
||
// if expr other_expr {
|
||
// ^ ^ ^- lookahead(1) is a brace
|
||
// | |- current token is not "else"
|
||
// |- (statement we just parsed)
|
||
//
|
||
// the place-inside-a-block suggestion would be more likely wrong than right.
|
||
//
|
||
// FIXME(compiler-errors): this should probably parse an arbitrary expr and not
|
||
// just lookahead one token, so we can see if there's a brace after _that_,
|
||
// since we want to protect against:
|
||
// `if 1 1 + 1 {` being suggested as `if { 1 } 1 + 1 {`
|
||
// + +
|
||
Ok(Some(_))
|
||
if (!self.token.is_keyword(kw::Else)
|
||
&& self.look_ahead(1, |t| t == &token::OpenBrace))
|
||
|| do_not_suggest_help => {}
|
||
// Do not suggest `if foo println!("") {;}` (as would be seen in test for #46836).
|
||
Ok(Some(Stmt { kind: StmtKind::Empty, .. })) => {}
|
||
Ok(Some(stmt)) => {
|
||
let stmt_own_line = self.psess.source_map().is_line_before_span_empty(sp);
|
||
let stmt_span = if stmt_own_line && self.eat(exp!(Semi)) {
|
||
// Expand the span to include the semicolon.
|
||
stmt.span.with_hi(self.prev_token.span.hi())
|
||
} else {
|
||
stmt.span
|
||
};
|
||
self.suggest_fixes_misparsed_for_loop_head(
|
||
&mut e,
|
||
prev.between(sp),
|
||
stmt_span,
|
||
&stmt.kind,
|
||
);
|
||
}
|
||
Err(e) => {
|
||
self.recover_stmt_(SemiColonMode::Break, BlockMode::Ignore);
|
||
e.cancel();
|
||
}
|
||
_ => {}
|
||
}
|
||
e.span_label(sp, "expected `{`");
|
||
e
|
||
}
|
||
|
||
fn suggest_fixes_misparsed_for_loop_head(
|
||
&self,
|
||
e: &mut Diag<'_>,
|
||
between: Span,
|
||
stmt_span: Span,
|
||
stmt_kind: &StmtKind,
|
||
) {
|
||
match (&self.token.kind, &stmt_kind) {
|
||
(token::OpenBrace, StmtKind::Expr(expr)) if let ExprKind::Call(..) = expr.kind => {
|
||
// for _ in x y() {}
|
||
e.span_suggestion_verbose(
|
||
between,
|
||
"you might have meant to write a method call",
|
||
".".to_string(),
|
||
Applicability::MaybeIncorrect,
|
||
);
|
||
}
|
||
(token::OpenBrace, StmtKind::Expr(expr)) if let ExprKind::Field(..) = expr.kind => {
|
||
// for _ in x y.z {}
|
||
e.span_suggestion_verbose(
|
||
between,
|
||
"you might have meant to write a field access",
|
||
".".to_string(),
|
||
Applicability::MaybeIncorrect,
|
||
);
|
||
}
|
||
(token::CloseBrace, StmtKind::Expr(expr))
|
||
if let ExprKind::Struct(expr) = &expr.kind
|
||
&& let None = expr.qself
|
||
&& expr.path.segments.len() == 1 =>
|
||
{
|
||
// This is specific to "mistyped `if` condition followed by empty body"
|
||
//
|
||
// for _ in x y {}
|
||
e.span_suggestion_verbose(
|
||
between,
|
||
"you might have meant to write a field access",
|
||
".".to_string(),
|
||
Applicability::MaybeIncorrect,
|
||
);
|
||
}
|
||
(token::OpenBrace, StmtKind::Expr(expr))
|
||
if let ExprKind::Lit(lit) = expr.kind
|
||
&& let None = lit.suffix
|
||
&& let token::LitKind::Integer | token::LitKind::Float = lit.kind =>
|
||
{
|
||
// for _ in x 0 {}
|
||
// for _ in x 0.0 {}
|
||
e.span_suggestion_verbose(
|
||
between,
|
||
format!("you might have meant to write a field access"),
|
||
".".to_string(),
|
||
Applicability::MaybeIncorrect,
|
||
);
|
||
}
|
||
(token::OpenBrace, StmtKind::Expr(expr))
|
||
if let ExprKind::Loop(..)
|
||
| ExprKind::If(..)
|
||
| ExprKind::While(..)
|
||
| ExprKind::Match(..)
|
||
| ExprKind::ForLoop { .. }
|
||
| ExprKind::TryBlock(..)
|
||
| ExprKind::Ret(..)
|
||
| ExprKind::Closure(..)
|
||
| ExprKind::Struct(..)
|
||
| ExprKind::Try(..) = expr.kind =>
|
||
{
|
||
// These are more likely to have been meant as a block body.
|
||
e.multipart_suggestion(
|
||
"you might have meant to write this as part of a block",
|
||
vec![
|
||
(stmt_span.shrink_to_lo(), "{ ".to_string()),
|
||
(stmt_span.shrink_to_hi(), " }".to_string()),
|
||
],
|
||
// Speculative; has been misleading in the past (#46836).
|
||
Applicability::MaybeIncorrect,
|
||
);
|
||
}
|
||
(token::OpenBrace, _) => {}
|
||
(_, _) => {
|
||
e.multipart_suggestion(
|
||
"you might have meant to write this as part of a block",
|
||
vec![
|
||
(stmt_span.shrink_to_lo(), "{ ".to_string()),
|
||
(stmt_span.shrink_to_hi(), " }".to_string()),
|
||
],
|
||
// Speculative; has been misleading in the past (#46836).
|
||
Applicability::MaybeIncorrect,
|
||
);
|
||
}
|
||
}
|
||
}
|
||
|
||
fn error_block_no_opening_brace<T>(&mut self) -> PResult<'a, T> {
|
||
let tok = super::token_descr(&self.token);
|
||
let msg = format!("expected `{{`, found {tok}");
|
||
Err(self.error_block_no_opening_brace_msg(Cow::from(msg)))
|
||
}
|
||
|
||
/// Parses a block. Inner attributes are allowed, block labels are not.
|
||
///
|
||
/// If `loop_header` is `Some` and an unexpected block label is encountered,
|
||
/// it is suggested to be moved just before `loop_header`, else it is suggested to be removed.
|
||
pub(super) fn parse_inner_attrs_and_block(
|
||
&mut self,
|
||
loop_header: Option<Span>,
|
||
) -> PResult<'a, (AttrVec, P<Block>)> {
|
||
self.parse_block_common(self.token.span, BlockCheckMode::Default, loop_header)
|
||
}
|
||
|
||
/// Parses a block. Inner attributes are allowed, block labels are not.
|
||
///
|
||
/// If `loop_header` is `Some` and an unexpected block label is encountered,
|
||
/// it is suggested to be moved just before `loop_header`, else it is suggested to be removed.
|
||
pub(super) fn parse_block_common(
|
||
&mut self,
|
||
lo: Span,
|
||
blk_mode: BlockCheckMode,
|
||
loop_header: Option<Span>,
|
||
) -> PResult<'a, (AttrVec, P<Block>)> {
|
||
if let Some(block) = self.eat_metavar_seq(MetaVarKind::Block, |this| this.parse_block()) {
|
||
return Ok((AttrVec::new(), block));
|
||
}
|
||
|
||
let maybe_ident = self.prev_token;
|
||
self.maybe_recover_unexpected_block_label(loop_header);
|
||
if !self.eat(exp!(OpenBrace)) {
|
||
return self.error_block_no_opening_brace();
|
||
}
|
||
|
||
let attrs = self.parse_inner_attributes()?;
|
||
let tail = match self.maybe_suggest_struct_literal(lo, blk_mode, maybe_ident) {
|
||
Some(tail) => tail?,
|
||
None => self.parse_block_tail(lo, blk_mode, AttemptLocalParseRecovery::Yes)?,
|
||
};
|
||
Ok((attrs, tail))
|
||
}
|
||
|
||
/// Parses the rest of a block expression or function body.
|
||
/// Precondition: already parsed the '{'.
|
||
pub(crate) fn parse_block_tail(
|
||
&mut self,
|
||
lo: Span,
|
||
s: BlockCheckMode,
|
||
recover: AttemptLocalParseRecovery,
|
||
) -> PResult<'a, P<Block>> {
|
||
let mut stmts = ThinVec::new();
|
||
let mut snapshot = None;
|
||
while !self.eat(exp!(CloseBrace)) {
|
||
if self.token == token::Eof {
|
||
break;
|
||
}
|
||
if self.is_vcs_conflict_marker(&TokenKind::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() => {
|
||
if let Some(ref mut snapshot) = snapshot {
|
||
snapshot.recover_vcs_conflict_marker();
|
||
}
|
||
if self.token == token::Colon {
|
||
// if a previous and next token of the current one is
|
||
// integer literal (e.g. `1:42`), it's likely a range
|
||
// expression for Pythonistas and we can suggest so.
|
||
if self.prev_token.is_integer_lit()
|
||
&& self.may_recover()
|
||
&& self.look_ahead(1, |token| token.is_integer_lit())
|
||
{
|
||
// FIXME(hkmatsumoto): Might be better to trigger
|
||
// this only when parsing an index expression.
|
||
err.span_suggestion_verbose(
|
||
self.token.span,
|
||
"you might have meant a range expression",
|
||
"..",
|
||
Applicability::MaybeIncorrect,
|
||
);
|
||
} else {
|
||
// if next token is following a colon, it's likely a path
|
||
// and we can suggest a path separator
|
||
self.bump();
|
||
if self.token.span.lo() == self.prev_token.span.hi() {
|
||
err.span_suggestion_verbose(
|
||
self.prev_token.span,
|
||
"maybe write a path separator here",
|
||
"::",
|
||
Applicability::MaybeIncorrect,
|
||
);
|
||
}
|
||
}
|
||
}
|
||
|
||
let guar = err.emit();
|
||
self.recover_stmt_(SemiColonMode::Ignore, BlockMode::Ignore);
|
||
Some(self.mk_stmt_err(self.token.span, guar))
|
||
}
|
||
Ok(stmt) => stmt,
|
||
Err(err) => return Err(err),
|
||
};
|
||
if let Some(stmt) = stmt {
|
||
stmts.push(stmt);
|
||
} else {
|
||
// Found only `;` or `}`.
|
||
continue;
|
||
};
|
||
}
|
||
Ok(self.mk_block(stmts, s, lo.to(self.prev_token.span)))
|
||
}
|
||
|
||
fn recover_missing_dot(&mut self, err: &mut Diag<'_>) {
|
||
let Some((ident, _)) = self.token.ident() else {
|
||
return;
|
||
};
|
||
if let Some(c) = ident.name.as_str().chars().next()
|
||
&& c.is_uppercase()
|
||
{
|
||
return;
|
||
}
|
||
if self.token.is_reserved_ident() && !self.token.is_ident_named(kw::Await) {
|
||
return;
|
||
}
|
||
if self.prev_token.is_reserved_ident() && self.prev_token.is_ident_named(kw::Await) {
|
||
// Likely `foo.await bar`
|
||
} else if !self.prev_token.is_reserved_ident() && self.prev_token.is_ident() {
|
||
// Likely `foo bar`
|
||
} else if self.prev_token.kind == token::Question {
|
||
// `foo? bar`
|
||
} else if self.prev_token.kind == token::CloseParen {
|
||
// `foo() bar`
|
||
} else {
|
||
return;
|
||
}
|
||
if self.token.span == self.prev_token.span {
|
||
// Account for syntax errors in proc-macros.
|
||
return;
|
||
}
|
||
if self.look_ahead(1, |t| [token::Semi, token::Question, token::Dot].contains(&t.kind)) {
|
||
err.span_suggestion_verbose(
|
||
self.prev_token.span.between(self.token.span),
|
||
"you might have meant to write a field access",
|
||
".".to_string(),
|
||
Applicability::MaybeIncorrect,
|
||
);
|
||
}
|
||
if self.look_ahead(1, |t| t.kind == token::OpenParen) {
|
||
err.span_suggestion_verbose(
|
||
self.prev_token.span.between(self.token.span),
|
||
"you might have meant to write a method call",
|
||
".".to_string(),
|
||
Applicability::MaybeIncorrect,
|
||
);
|
||
}
|
||
}
|
||
|
||
/// Parses a statement, including the trailing semicolon.
|
||
pub fn parse_full_stmt(
|
||
&mut self,
|
||
recover: AttemptLocalParseRecovery,
|
||
) -> PResult<'a, Option<Stmt>> {
|
||
// Skip looking for a trailing semicolon when we have a metavar seq.
|
||
if let Some(stmt) = self.eat_metavar_seq(MetaVarKind::Stmt, |this| {
|
||
// Why pass `true` for `force_full_expr`? Statement expressions are less expressive
|
||
// than "full" expressions, due to the `STMT_EXPR` restriction, and sometimes need
|
||
// parentheses. E.g. the "full" expression `match paren_around_match {} | true` when
|
||
// used in statement context must be written `(match paren_around_match {} | true)`.
|
||
// However, if the expression we are parsing in this statement context was pasted by a
|
||
// declarative macro, it may have come from a "full" expression context, and lack
|
||
// these parentheses. So we lift the `STMT_EXPR` restriction to ensure the statement
|
||
// will reparse successfully.
|
||
this.parse_stmt_without_recovery(false, ForceCollect::No, true)
|
||
}) {
|
||
let stmt = stmt.expect("an actual statement");
|
||
return Ok(Some(stmt));
|
||
}
|
||
|
||
let Some(mut stmt) = self.parse_stmt_without_recovery(true, ForceCollect::No, false)?
|
||
else {
|
||
return Ok(None);
|
||
};
|
||
|
||
let mut eat_semi = true;
|
||
let mut add_semi_to_stmt = false;
|
||
|
||
match &mut stmt.kind {
|
||
// Expression without semicolon.
|
||
StmtKind::Expr(expr)
|
||
if classify::expr_requires_semi_to_be_stmt(expr)
|
||
&& !expr.attrs.is_empty()
|
||
&& !matches!(self.token.kind, token::Eof | token::Semi | token::CloseBrace) =>
|
||
{
|
||
// The user has written `#[attr] expr` which is unsupported. (#106020)
|
||
let guar = self.attr_on_non_tail_expr(&expr);
|
||
// We already emitted an error, so don't emit another type error
|
||
let sp = expr.span.to(self.prev_token.span);
|
||
*expr = self.mk_expr_err(sp, guar);
|
||
}
|
||
|
||
// Expression without semicolon.
|
||
StmtKind::Expr(expr)
|
||
if self.token != token::Eof && classify::expr_requires_semi_to_be_stmt(expr) =>
|
||
{
|
||
// Just check for errors and recover; do not eat semicolon yet.
|
||
|
||
let expect_result = self.expect_one_of(&[], &[exp!(Semi), exp!(CloseBrace)]);
|
||
|
||
// Try to both emit a better diagnostic, and avoid further errors by replacing
|
||
// the `expr` with `ExprKind::Err`.
|
||
let replace_with_err = 'break_recover: {
|
||
match expect_result {
|
||
Ok(Recovered::No) => None,
|
||
Ok(Recovered::Yes(guar)) => {
|
||
// Skip type error to avoid extra errors.
|
||
Some(guar)
|
||
}
|
||
Err(e) => {
|
||
if self.recover_colon_as_semi() {
|
||
// recover_colon_as_semi has already emitted a nicer error.
|
||
e.delay_as_bug();
|
||
add_semi_to_stmt = true;
|
||
eat_semi = false;
|
||
|
||
break 'break_recover None;
|
||
}
|
||
|
||
match &expr.kind {
|
||
ExprKind::Path(None, ast::Path { segments, .. })
|
||
if let [segment] = segments.as_slice() =>
|
||
{
|
||
if self.token == token::Colon
|
||
&& self.look_ahead(1, |token| {
|
||
token.is_metavar_block()
|
||
|| matches!(
|
||
token.kind,
|
||
token::Ident(
|
||
kw::For | kw::Loop | kw::While,
|
||
token::IdentIsRaw::No
|
||
) | token::OpenBrace
|
||
)
|
||
})
|
||
{
|
||
let snapshot = self.create_snapshot_for_diagnostic();
|
||
let label = Label {
|
||
ident: Ident::from_str_and_span(
|
||
&format!("'{}", segment.ident),
|
||
segment.ident.span,
|
||
),
|
||
};
|
||
match self.parse_expr_labeled(label, false) {
|
||
Ok(labeled_expr) => {
|
||
e.cancel();
|
||
self.dcx().emit_err(MalformedLoopLabel {
|
||
span: label.ident.span,
|
||
suggestion: label.ident.span.shrink_to_lo(),
|
||
});
|
||
*expr = labeled_expr;
|
||
break 'break_recover None;
|
||
}
|
||
Err(err) => {
|
||
err.cancel();
|
||
self.restore_snapshot(snapshot);
|
||
}
|
||
}
|
||
}
|
||
}
|
||
_ => {}
|
||
}
|
||
|
||
let res =
|
||
self.check_mistyped_turbofish_with_multiple_type_params(e, expr);
|
||
|
||
Some(if recover.no() {
|
||
res?
|
||
} else {
|
||
res.unwrap_or_else(|mut e| {
|
||
self.recover_missing_dot(&mut e);
|
||
let guar = e.emit();
|
||
self.recover_stmt();
|
||
guar
|
||
})
|
||
})
|
||
}
|
||
}
|
||
};
|
||
|
||
if let Some(guar) = replace_with_err {
|
||
// We already emitted an error, so don't emit another type error
|
||
let sp = expr.span.to(self.prev_token.span);
|
||
*expr = self.mk_expr_err(sp, guar);
|
||
}
|
||
}
|
||
StmtKind::Expr(_) | StmtKind::MacCall(_) => {}
|
||
StmtKind::Let(local) if let Err(mut e) = self.expect_semi() => {
|
||
// We might be at the `,` in `let x = foo<bar, baz>;`. Try to recover.
|
||
match &mut local.kind {
|
||
LocalKind::Init(expr) | LocalKind::InitElse(expr, _) => {
|
||
self.check_mistyped_turbofish_with_multiple_type_params(e, expr).map_err(
|
||
|mut e| {
|
||
self.recover_missing_dot(&mut e);
|
||
e
|
||
},
|
||
)?;
|
||
// We found `foo<bar, baz>`, have we fully recovered?
|
||
self.expect_semi()?;
|
||
}
|
||
LocalKind::Decl => {
|
||
if let Some(colon_sp) = local.colon_sp {
|
||
e.span_label(
|
||
colon_sp,
|
||
format!(
|
||
"while parsing the type for {}",
|
||
local.pat.descr().map_or_else(
|
||
|| "the binding".to_string(),
|
||
|n| format!("`{n}`")
|
||
)
|
||
),
|
||
);
|
||
let suggest_eq = if self.token == token::Dot
|
||
&& let _ = self.bump()
|
||
&& let mut snapshot = self.create_snapshot_for_diagnostic()
|
||
&& let Ok(_) = snapshot
|
||
.parse_dot_suffix_expr(
|
||
colon_sp,
|
||
self.mk_expr_err(
|
||
colon_sp,
|
||
self.dcx()
|
||
.delayed_bug("error during `:` -> `=` recovery"),
|
||
),
|
||
)
|
||
.map_err(Diag::cancel)
|
||
{
|
||
true
|
||
} else if let Some(op) = self.check_assoc_op()
|
||
&& op.node.can_continue_expr_unambiguously()
|
||
{
|
||
true
|
||
} else {
|
||
false
|
||
};
|
||
if suggest_eq {
|
||
e.span_suggestion_short(
|
||
colon_sp,
|
||
"use `=` if you meant to assign",
|
||
"=",
|
||
Applicability::MaybeIncorrect,
|
||
);
|
||
}
|
||
}
|
||
return Err(e);
|
||
}
|
||
}
|
||
eat_semi = false;
|
||
}
|
||
StmtKind::Empty | StmtKind::Item(_) | StmtKind::Let(_) | StmtKind::Semi(_) => {
|
||
eat_semi = false
|
||
}
|
||
}
|
||
|
||
if add_semi_to_stmt || (eat_semi && self.eat(exp!(Semi))) {
|
||
stmt = stmt.add_trailing_semicolon();
|
||
}
|
||
|
||
stmt.span = stmt.span.to(self.prev_token.span);
|
||
Ok(Some(stmt))
|
||
}
|
||
|
||
pub(super) fn mk_block(
|
||
&self,
|
||
stmts: ThinVec<Stmt>,
|
||
rules: BlockCheckMode,
|
||
span: Span,
|
||
) -> P<Block> {
|
||
P(Block { stmts, id: DUMMY_NODE_ID, rules, span, tokens: None })
|
||
}
|
||
|
||
pub(super) fn mk_stmt(&self, span: Span, kind: StmtKind) -> Stmt {
|
||
Stmt { id: DUMMY_NODE_ID, kind, span }
|
||
}
|
||
|
||
pub(super) fn mk_stmt_err(&self, span: Span, guar: ErrorGuaranteed) -> Stmt {
|
||
self.mk_stmt(span, StmtKind::Expr(self.mk_expr_err(span, guar)))
|
||
}
|
||
|
||
pub(super) fn mk_block_err(&self, span: Span, guar: ErrorGuaranteed) -> P<Block> {
|
||
self.mk_block(thin_vec![self.mk_stmt_err(span, guar)], BlockCheckMode::Default, span)
|
||
}
|
||
}
|