Struct rustc_ast_pretty::pprust::state::expr::FixupContext

pub(crate) struct FixupContext {
    pub stmt: bool,
    pub leftmost_subexpression_in_stmt: bool,
    pub parenthesize_exterior_struct_lit: bool,
}

Fields

stmt: bool

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

leftmost_subexpression_in_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.

parenthesize_exterior_struct_lit: bool

This is the difference between:

if let _ = (Struct {}) {}  // needs parens

match () {
    () if let _ = Struct {} => {}  // no parens
}

Trait Implementations

impl Clone for FixupContext

fn clone(&self) -> FixupContext

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for FixupContext

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for FixupContext

The default amount of fixing is minimal fixing. Fixups should be turned on in a targetted fashion where needed.

fn default() -> Self

Returns the “default value” for a type.

impl Copy for FixupContext

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 3 bytes