From 034dd340b08be1f2f0477ad16131d609f9dbd53c Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 30 Aug 2026 09:22:00 -0700 Subject: Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing fixes from Steven Rostedt: - Fix error output of boot instance creation failure Currently if a boot instance creation fails, instead of printing out the name of the instance that failed, it prints "(null)". That is because it prints "cur_str" that had already been processed by strsep(). Print the saved name instead. While at it, print the error code of the failure. - Fix use-after-free for same named historgrams Histograms can be named so that they can be used in multiple events. But if the named histogram has a variable attached, the second event that uses the named histogram which duplicates it and needs to free the original after duplication leaves the old variable in place and still visible. If another histogram uses than variable, it will use the stale one which will try to reference the freed duplicate histogram and crash the kernel. Free the duplicate variables along with the duplicated histogram data. - Check return value of kthread_run() in event self test The events self tests uses a kthread for testing but does not check if it succeeded in creating a kthread. If the kthread creation were to fail, the code will still try to call kthread_stop() on the error returned. - Fix race between reading trace_pipe and updating subbuffer size If a user is reading the trace_pipe file at the same time they update the ring buffer sub-buffer size, can cause the trace_pipe read to read stale data. Add trace_access_lock() around updating the ring buffer sub-buffer size. - Fix eventfs_inode on failure path in creation of the events directory In the creation of the "events" directory, if after allocating the eventfs_inode a failure is detected, it calls cleanup_ei() which calls free_ei(). The free_ei() will test if eventfs_inode being freed has no children. It is a bug if it does. But on the failure case of the creation of the "events" directory, the children lists have not yet been initialized and the free will trigger a warning because list_empty() on an uninitialized list returns false. Move the initialization into init_ei() where it makes more sense and makes sure that a created eventfs_inode has its lists initialized upon creation. - Check return value of kthread_run() in ftrace direct sample code The sample code that shows how to use the ftrace direct calls does not test the return of kthread_run() to see if it succeeds. Return a failure if the kthread_run() doesn't succeed. - Clear user events state on fork in case of alloc failure On fork, the child gets a pointer to the parent's user events state. It makes a copy of it then updates the child's pointer to it. But if the allocation fails, the duplication function leaves the child with a pointer to its parent's descriptor. When the child cleans up its data, it will free the parent's descriptor while the parent is still using it. In the duplication function, set the child's user_event_mm to NULL before testing if the allocation succeeded, and when it exits it will not free the parent's descriptor. - Fix retry exhaustion in simple ring buffer reader swap simple_ring_buffer_swap_reader_page() starts with retry set to 8 and post-decrements it only after a failed link replacement. On the final attempt, a successful replacement leaves retry at zero, while a failed replacement leaves it at -1. But the check for success expects the retry value to be non-zero and exits with an error on zero. This is the opposite result. Fix it. - Fail nicely when the remote swap_reader_page() returns an error Currently, if the swap_reader_page() of a remote buffer fails, it triggers a WARN_ON_ONCE() and continues normally. Instead, have it exit with an error and a pr_warn() print instead of a full WARNING. * tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: ring-buffer: Stop remote reader update when page swap fails tracing: Fix retry exhaustion in simple ring buffer reader swap tracing/user_events: Clear copied tracing state before fork duplication samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify eventfs: Initialize ei->children and ei->list in init_ei() tracing: Fix use-after-free in trace_pipe read on sub-buffer order change tracing: Fix crash passing ERR_PTR to kthread_stop() tracing: Fix use-after-free with same-name named triggers tracing: Fix logged instance name on creation failure --- rust/syn/fixup.rs | 775 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 775 insertions(+) create mode 100644 rust/syn/fixup.rs (limited to 'rust/syn/fixup.rs') diff --git a/rust/syn/fixup.rs b/rust/syn/fixup.rs new file mode 100644 index 000000000..79b6d7618 --- /dev/null +++ b/rust/syn/fixup.rs @@ -0,0 +1,775 @@ +// SPDX-License-Identifier: Apache-2.0 OR MIT + +use crate::classify; +use crate::expr::Expr; +#[cfg(feature = "full")] +use crate::expr::{ + ExprBreak, ExprRange, ExprRawAddr, ExprReference, ExprReturn, ExprUnary, ExprYield, +}; +use crate::precedence::Precedence; +#[cfg(feature = "full")] +use crate::ty::ReturnType; + +pub(crate) struct FixupContext { + #[cfg(feature = "full")] + previous_operator: Precedence, + #[cfg(feature = "full")] + next_operator: Precedence, + + // Print expression such that it can be parsed back as a statement + // consisting of the original expression. + // + // The effect of this is for binary operators in statement position to set + // `leftmost_subexpression_in_stmt` when printing their left-hand operand. + // + // (match x {}) - 1; // match needs parens when LHS of binary operator + // + // match x {}; // not when its own statement + // + #[cfg(feature = "full")] + stmt: bool, + + // This is the difference between: + // + // (match x {}) - 1; // subexpression needs parens + // + // let _ = match x {} - 1; // no parens + // + // There are 3 distinguishable contexts in which `print_expr` might be + // called with the expression `$match` as its argument, where `$match` + // represents an expression of kind `ExprKind::Match`: + // + // - stmt=false leftmost_subexpression_in_stmt=false + // + // Example: `let _ = $match - 1;` + // + // No parentheses required. + // + // - stmt=false leftmost_subexpression_in_stmt=true + // + // Example: `$match - 1;` + // + // Must parenthesize `($match)`, otherwise parsing back the output as a + // statement would terminate the statement after the closing brace of + // the match, parsing `-1;` as a separate statement. + // + // - stmt=true leftmost_subexpression_in_stmt=false + // + // Example: `$match;` + // + // No parentheses required. + #[cfg(feature = "full")] + leftmost_subexpression_in_stmt: bool, + + // Print expression such that it can be parsed as a match arm. + // + // This is almost equivalent to `stmt`, but the grammar diverges a tiny bit + // between statements and match arms when it comes to braced macro calls. + // Macro calls with brace delimiter terminate a statement without a + // semicolon, but do not terminate a match-arm without comma. + // + // m! {} - 1; // two statements: a macro call followed by -1 literal + // + // match () { + // _ => m! {} - 1, // binary subtraction operator + // } + // + #[cfg(feature = "full")] + match_arm: bool, + + // This is almost equivalent to `leftmost_subexpression_in_stmt`, other than + // for braced macro calls. + // + // If we have `m! {} - 1` as an expression, the leftmost subexpression + // `m! {}` will need to be parenthesized in the statement case but not the + // match-arm case. + // + // (m! {}) - 1; // subexpression needs parens + // + // match () { + // _ => m! {} - 1, // no parens + // } + // + #[cfg(feature = "full")] + leftmost_subexpression_in_match_arm: bool, + + // This is the difference between: + // + // if let _ = (Struct {}) {} // needs parens + // + // match () { + // () if let _ = Struct {} => {} // no parens + // } + // + #[cfg(feature = "full")] + condition: bool, + + // This is the difference between: + // + // if break Struct {} == (break) {} // needs parens + // + // if break break == Struct {} {} // no parens + // + #[cfg(feature = "full")] + rightmost_subexpression_in_condition: bool, + + // This is the difference between: + // + // if break ({ x }).field + 1 {} needs parens + // + // if break 1 + { x }.field {} // no parens + // + #[cfg(feature = "full")] + leftmost_subexpression_in_optional_operand: bool, + + // This is the difference between: + // + // let _ = (return) - 1; // without paren, this would return -1 + // + // let _ = return + 1; // no paren because '+' cannot begin expr + // + #[cfg(feature = "full")] + next_operator_can_begin_expr: bool, + + // This is the difference between: + // + // let _ = 1 + return 1; // no parens if rightmost subexpression + // + // let _ = 1 + (return 1) + 1; // needs parens + // + #[cfg(feature = "full")] + next_operator_can_continue_expr: bool, + + // This is the difference between: + // + // let _ = x as u8 + T; + // + // let _ = (x as u8) < T; + // + // Without parens, the latter would want to parse `u8 Self { + FixupContext { + stmt: true, + ..FixupContext::NONE + } + } + + /// Create the initial fixup for printing an expression as the right-hand + /// side of a match arm. + #[cfg(feature = "full")] + pub fn new_match_arm() -> Self { + FixupContext { + match_arm: true, + ..FixupContext::NONE + } + } + + /// Create the initial fixup for printing an expression as the "condition" + /// of an `if` or `while`. There are a few other positions which are + /// grammatically equivalent and also use this, such as the iterator + /// expression in `for` and the scrutinee in `match`. + #[cfg(feature = "full")] + pub fn new_condition() -> Self { + FixupContext { + condition: true, + rightmost_subexpression_in_condition: true, + ..FixupContext::NONE + } + } + + /// Transform this fixup into the one that should apply when printing the + /// leftmost subexpression of the current expression. + /// + /// The leftmost subexpression is any subexpression that has the same first + /// token as the current expression, but has a different last token. + /// + /// For example in `$a + $b` and `$a.method()`, the subexpression `$a` is a + /// leftmost subexpression. + /// + /// Not every expression has a leftmost subexpression. For example neither + /// `-$a` nor `[$a]` have one. + pub fn leftmost_subexpression_with_operator( + self, + expr: &Expr, + #[cfg(feature = "full")] next_operator_can_begin_expr: bool, + next_operator_can_begin_generics: bool, + #[cfg(feature = "full")] precedence: Precedence, + ) -> (Precedence, Self) { + let fixup = FixupContext { + #[cfg(feature = "full")] + next_operator: precedence, + #[cfg(feature = "full")] + stmt: false, + #[cfg(feature = "full")] + leftmost_subexpression_in_stmt: self.stmt || self.leftmost_subexpression_in_stmt, + #[cfg(feature = "full")] + match_arm: false, + #[cfg(feature = "full")] + leftmost_subexpression_in_match_arm: self.match_arm + || self.leftmost_subexpression_in_match_arm, + #[cfg(feature = "full")] + rightmost_subexpression_in_condition: false, + #[cfg(feature = "full")] + next_operator_can_begin_expr, + #[cfg(feature = "full")] + next_operator_can_continue_expr: true, + next_operator_can_begin_generics, + ..self + }; + + (fixup.leftmost_subexpression_precedence(expr), fixup) + } + + /// Transform this fixup into the one that should apply when printing a + /// leftmost subexpression followed by a `.` or `?` token, which confer + /// different statement boundary rules compared to other leftmost + /// subexpressions. + pub fn leftmost_subexpression_with_dot(self, expr: &Expr) -> (Precedence, Self) { + let fixup = FixupContext { + #[cfg(feature = "full")] + next_operator: Precedence::Unambiguous, + #[cfg(feature = "full")] + stmt: self.stmt || self.leftmost_subexpression_in_stmt, + #[cfg(feature = "full")] + leftmost_subexpression_in_stmt: false, + #[cfg(feature = "full")] + match_arm: self.match_arm || self.leftmost_subexpression_in_match_arm, + #[cfg(feature = "full")] + leftmost_subexpression_in_match_arm: false, + #[cfg(feature = "full")] + rightmost_subexpression_in_condition: false, + #[cfg(feature = "full")] + next_operator_can_begin_expr: false, + #[cfg(feature = "full")] + next_operator_can_continue_expr: true, + next_operator_can_begin_generics: false, + ..self + }; + + (fixup.leftmost_subexpression_precedence(expr), fixup) + } + + fn leftmost_subexpression_precedence(self, expr: &Expr) -> Precedence { + #[cfg(feature = "full")] + if !self.next_operator_can_begin_expr || self.next_operator == Precedence::Range { + if let Scan::Bailout = scan_right(expr, self, Precedence::MIN, 0, 0) { + if scan_left(expr, self) { + return Precedence::Unambiguous; + } + } + } + + self.precedence(expr) + } + + /// Transform this fixup into the one that should apply when printing the + /// rightmost subexpression of the current expression. + /// + /// The rightmost subexpression is any subexpression that has a different + /// first token than the current expression, but has the same last token. + /// + /// For example in `$a + $b` and `-$b`, the subexpression `$b` is a + /// rightmost subexpression. + /// + /// Not every expression has a rightmost subexpression. For example neither + /// `[$b]` nor `$a.f($b)` have one. + pub fn rightmost_subexpression( + self, + expr: &Expr, + #[cfg(feature = "full")] precedence: Precedence, + ) -> (Precedence, Self) { + let fixup = self.rightmost_subexpression_fixup( + #[cfg(feature = "full")] + false, + #[cfg(feature = "full")] + false, + #[cfg(feature = "full")] + precedence, + ); + (fixup.rightmost_subexpression_precedence(expr), fixup) + } + + pub fn rightmost_subexpression_fixup( + self, + #[cfg(feature = "full")] reset_allow_struct: bool, + #[cfg(feature = "full")] optional_operand: bool, + #[cfg(feature = "full")] precedence: Precedence, + ) -> Self { + FixupContext { + #[cfg(feature = "full")] + previous_operator: precedence, + #[cfg(feature = "full")] + stmt: false, + #[cfg(feature = "full")] + leftmost_subexpression_in_stmt: false, + #[cfg(feature = "full")] + match_arm: false, + #[cfg(feature = "full")] + leftmost_subexpression_in_match_arm: false, + #[cfg(feature = "full")] + condition: self.condition && !reset_allow_struct, + #[cfg(feature = "full")] + leftmost_subexpression_in_optional_operand: self.condition && optional_operand, + ..self + } + } + + pub fn rightmost_subexpression_precedence(self, expr: &Expr) -> Precedence { + let default_prec = self.precedence(expr); + + #[cfg(feature = "full")] + if match self.previous_operator { + Precedence::Assign | Precedence::Let | Precedence::Prefix => { + default_prec < self.previous_operator + } + _ => default_prec <= self.previous_operator, + } && match self.next_operator { + Precedence::Range | Precedence::Or | Precedence::And => true, + _ => !self.next_operator_can_begin_expr, + } { + if let Scan::Bailout | Scan::Fail = scan_right(expr, self, self.previous_operator, 1, 0) + { + if scan_left(expr, self) { + return Precedence::Prefix; + } + } + } + + default_prec + } + + /// Determine whether parentheses are needed around the given expression to + /// head off the early termination of a statement or condition. + #[cfg(feature = "full")] + pub fn parenthesize(self, expr: &Expr) -> bool { + (self.leftmost_subexpression_in_stmt && !classify::requires_semi_to_be_stmt(expr)) + || ((self.stmt || self.leftmost_subexpression_in_stmt) && matches!(expr, Expr::Let(_))) + || (self.leftmost_subexpression_in_match_arm + && !classify::requires_comma_to_be_match_arm(expr)) + || (self.condition && matches!(expr, Expr::Struct(_))) + || (self.rightmost_subexpression_in_condition + && matches!( + expr, + Expr::Return(ExprReturn { expr: None, .. }) + | Expr::Yield(ExprYield { expr: None, .. }) + )) + || (self.rightmost_subexpression_in_condition + && !self.condition + && matches!( + expr, + Expr::Break(ExprBreak { expr: None, .. }) + | Expr::Path(_) + | Expr::Range(ExprRange { end: None, .. }) + )) + || (self.leftmost_subexpression_in_optional_operand + && matches!(expr, Expr::Block(expr) if expr.attrs.is_empty() && expr.label.is_none())) + } + + /// Determines the effective precedence of a subexpression. Some expressions + /// have higher or lower precedence when adjacent to particular operators. + fn precedence(self, expr: &Expr) -> Precedence { + #[cfg(feature = "full")] + if self.next_operator_can_begin_expr { + // Decrease precedence of value-less jumps when followed by an + // operator that would otherwise get interpreted as beginning a + // value for the jump. + if let Expr::Break(ExprBreak { expr: None, .. }) + | Expr::Return(ExprReturn { expr: None, .. }) + | Expr::Yield(ExprYield { expr: None, .. }) = expr + { + return Precedence::Jump; + } + } + + #[cfg(feature = "full")] + if !self.next_operator_can_continue_expr { + match expr { + // Increase precedence of expressions that extend to the end of + // current statement or group. + Expr::Break(_) + | Expr::Closure(_) + | Expr::Let(_) + | Expr::Return(_) + | Expr::Yield(_) => { + return Precedence::Prefix; + } + Expr::Range(e) if e.start.is_none() => return Precedence::Prefix, + _ => {} + } + } + + if self.next_operator_can_begin_generics { + if let Expr::Cast(cast) = expr { + if classify::trailing_unparameterized_path(&cast.ty) { + return Precedence::MIN; + } + } + } + + Precedence::of(expr) + } +} + +impl Copy for FixupContext {} + +impl Clone for FixupContext { + fn clone(&self) -> Self { + *self + } +} + +#[cfg(feature = "full")] +enum Scan { + Fail, + Bailout, + Consume, +} + +#[cfg(feature = "full")] +impl Copy for Scan {} + +#[cfg(feature = "full")] +impl Clone for Scan { + fn clone(&self) -> Self { + *self + } +} + +#[cfg(feature = "full")] +impl PartialEq for Scan { + fn eq(&self, other: &Self) -> bool { + *self as u8 == *other as u8 + } +} + +#[cfg(feature = "full")] +fn scan_left(expr: &Expr, fixup: FixupContext) -> bool { + match expr { + Expr::Assign(_) => fixup.previous_operator <= Precedence::Assign, + Expr::Binary(e) => match Precedence::of_binop(&e.op) { + Precedence::Assign => fixup.previous_operator <= Precedence::Assign, + binop_prec => fixup.previous_operator < binop_prec, + }, + Expr::Cast(_) => fixup.previous_operator < Precedence::Cast, + Expr::Range(e) => e.start.is_none() || fixup.previous_operator < Precedence::Assign, + _ => true, + } +} + +#[cfg(feature = "full")] +fn scan_right( + expr: &Expr, + fixup: FixupContext, + precedence: Precedence, + fail_offset: u8, + bailout_offset: u8, +) -> Scan { + let consume_by_precedence = if match precedence { + Precedence::Assign | Precedence::Compare => precedence <= fixup.next_operator, + _ => precedence < fixup.next_operator, + } || fixup.next_operator == Precedence::MIN + { + Scan::Consume + } else { + Scan::Bailout + }; + if fixup.parenthesize(expr) { + return consume_by_precedence; + } + match expr { + Expr::Assign(e) if e.attrs.is_empty() => { + if match fixup.next_operator { + Precedence::Unambiguous => fail_offset >= 2, + _ => bailout_offset >= 1, + } { + return Scan::Consume; + } + let right_fixup = fixup.rightmost_subexpression_fixup(false, false, Precedence::Assign); + let scan = scan_right( + &e.right, + right_fixup, + Precedence::Assign, + match fixup.next_operator { + Precedence::Unambiguous => fail_offset, + _ => 1, + }, + 1, + ); + if let Scan::Bailout | Scan::Consume = scan { + Scan::Consume + } else if let Precedence::Unambiguous = fixup.next_operator { + Scan::Fail + } else { + Scan::Bailout + } + } + Expr::Binary(e) if e.attrs.is_empty() => { + if match fixup.next_operator { + Precedence::Unambiguous => { + fail_offset >= 2 + && (consume_by_precedence == Scan::Consume || bailout_offset >= 1) + } + _ => bailout_offset >= 1, + } { + return Scan::Consume; + } + let binop_prec = Precedence::of_binop(&e.op); + if binop_prec == Precedence::Compare && fixup.next_operator == Precedence::Compare { + return Scan::Consume; + } + let right_fixup = fixup.rightmost_subexpression_fixup(false, false, binop_prec); + let scan = scan_right( + &e.right, + right_fixup, + binop_prec, + match fixup.next_operator { + Precedence::Unambiguous => fail_offset, + _ => 1, + }, + consume_by_precedence as u8 - Scan::Bailout as u8, + ); + match scan { + Scan::Fail => {} + Scan::Bailout => return consume_by_precedence, + Scan::Consume => return Scan::Consume, + } + let right_needs_group = binop_prec != Precedence::Assign + && right_fixup.rightmost_subexpression_precedence(&e.right) <= binop_prec; + if right_needs_group { + consume_by_precedence + } else if let (Scan::Fail, Precedence::Unambiguous) = (scan, fixup.next_operator) { + Scan::Fail + } else { + Scan::Bailout + } + } + Expr::RawAddr(ExprRawAddr { expr, .. }) + | Expr::Reference(ExprReference { expr, .. }) + | Expr::Unary(ExprUnary { expr, .. }) => { + if match fixup.next_operator { + Precedence::Unambiguous => { + fail_offset >= 2 + && (consume_by_precedence == Scan::Consume || bailout_offset >= 1) + } + _ => bailout_offset >= 1, + } { + return Scan::Consume; + } + let right_fixup = fixup.rightmost_subexpression_fixup(false, false, Precedence::Prefix); + let scan = scan_right( + expr, + right_fixup, + precedence, + match fixup.next_operator { + Precedence::Unambiguous => fail_offset, + _ => 1, + }, + consume_by_precedence as u8 - Scan::Bailout as u8, + ); + match scan { + Scan::Fail => {} + Scan::Bailout => return consume_by_precedence, + Scan::Consume => return Scan::Consume, + } + if right_fixup.rightmost_subexpression_precedence(expr) < Precedence::Prefix { + consume_by_precedence + } else if let (Scan::Fail, Precedence::Unambiguous) = (scan, fixup.next_operator) { + Scan::Fail + } else { + Scan::Bailout + } + } + Expr::Range(e) if e.attrs.is_empty() => match &e.end { + Some(end) => { + if fail_offset >= 2 { + return Scan::Consume; + } + let right_fixup = + fixup.rightmost_subexpression_fixup(false, true, Precedence::Range); + let scan = scan_right( + end, + right_fixup, + Precedence::Range, + fail_offset, + match fixup.next_operator { + Precedence::Assign | Precedence::Range => 0, + _ => 1, + }, + ); + if match (scan, fixup.next_operator) { + (Scan::Fail, _) => false, + (Scan::Bailout, Precedence::Assign | Precedence::Range) => false, + (Scan::Bailout | Scan::Consume, _) => true, + } { + return Scan::Consume; + } + if right_fixup.rightmost_subexpression_precedence(end) <= Precedence::Range { + Scan::Consume + } else { + Scan::Fail + } + } + None => { + if fixup.next_operator_can_begin_expr { + Scan::Consume + } else { + Scan::Fail + } + } + }, + Expr::Break(e) => match &e.expr { + Some(value) => { + if bailout_offset >= 1 || e.label.is_none() && classify::expr_leading_label(value) { + return Scan::Consume; + } + let right_fixup = fixup.rightmost_subexpression_fixup(true, true, Precedence::Jump); + match scan_right(value, right_fixup, Precedence::Jump, 1, 1) { + Scan::Fail => Scan::Bailout, + Scan::Bailout | Scan::Consume => Scan::Consume, + } + } + None => match fixup.next_operator { + Precedence::Assign if precedence > Precedence::Assign => Scan::Fail, + _ => Scan::Consume, + }, + }, + Expr::Return(ExprReturn { expr, .. }) | Expr::Yield(ExprYield { expr, .. }) => match expr { + Some(e) => { + if bailout_offset >= 1 { + return Scan::Consume; + } + let right_fixup = + fixup.rightmost_subexpression_fixup(true, false, Precedence::Jump); + match scan_right(e, right_fixup, Precedence::Jump, 1, 1) { + Scan::Fail => Scan::Bailout, + Scan::Bailout | Scan::Consume => Scan::Consume, + } + } + None => match fixup.next_operator { + Precedence::Assign if precedence > Precedence::Assign => Scan::Fail, + _ => Scan::Consume, + }, + }, + Expr::Closure(e) => { + if matches!(e.output, ReturnType::Default) + || matches!(&*e.body, Expr::Block(body) if body.attrs.is_empty() && body.label.is_none()) + { + if bailout_offset >= 1 { + return Scan::Consume; + } + let right_fixup = + fixup.rightmost_subexpression_fixup(false, false, Precedence::Jump); + match scan_right(&e.body, right_fixup, Precedence::Jump, 1, 1) { + Scan::Fail => Scan::Bailout, + Scan::Bailout | Scan::Consume => Scan::Consume, + } + } else { + Scan::Consume + } + } + Expr::Let(e) => { + if bailout_offset >= 1 { + return Scan::Consume; + } + let right_fixup = fixup.rightmost_subexpression_fixup(false, false, Precedence::Let); + let scan = scan_right( + &e.expr, + right_fixup, + Precedence::Let, + 1, + if fixup.next_operator < Precedence::Let { + 0 + } else { + 1 + }, + ); + match scan { + Scan::Fail | Scan::Bailout if fixup.next_operator < Precedence::Let => { + return Scan::Bailout; + } + Scan::Consume => return Scan::Consume, + _ => {} + } + if right_fixup.rightmost_subexpression_precedence(&e.expr) < Precedence::Let { + Scan::Consume + } else if let Scan::Fail = scan { + Scan::Bailout + } else { + Scan::Consume + } + } + Expr::Array(_) + | Expr::Assign(_) + | Expr::Async(_) + | Expr::Await(_) + | Expr::Binary(_) + | Expr::Block(_) + | Expr::Call(_) + | Expr::Cast(_) + | Expr::Const(_) + | Expr::Continue(_) + | Expr::Field(_) + | Expr::ForLoop(_) + | Expr::Group(_) + | Expr::If(_) + | Expr::Index(_) + | Expr::Infer(_) + | Expr::Lit(_) + | Expr::Loop(_) + | Expr::Macro(_) + | Expr::Match(_) + | Expr::MethodCall(_) + | Expr::Paren(_) + | Expr::Path(_) + | Expr::Range(_) + | Expr::Repeat(_) + | Expr::Struct(_) + | Expr::Try(_) + | Expr::TryBlock(_) + | Expr::Tuple(_) + | Expr::Unsafe(_) + | Expr::Verbatim(_) + | Expr::While(_) => match fixup.next_operator { + Precedence::Assign | Precedence::Range if precedence == Precedence::Range => Scan::Fail, + _ if precedence == Precedence::Let && fixup.next_operator < Precedence::Let => { + Scan::Fail + } + _ => consume_by_precedence, + }, + } +} -- cgit v1.3.1