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Support flattening/inlining format_args through & and ().

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E.g. format_args!("{}", &(format_args!("abc"))).
This commit is contained in:
Mara Bos 2023-01-13 18:00:56 +01:00
parent 85ef2f0cfe
commit caa6ba9e86
2 changed files with 21 additions and 6 deletions
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9
compiler/rustc_ast/src/ast.rs
View File

@ -1184,6 +1184,15 @@ impl Expr {
expr
}
pub fn peel_parens_and_refs(&self) -> &Expr {
let mut expr = self;
while let ExprKind::Paren(inner) | ExprKind::AddrOf(BorrowKind::Ref, _, inner) = &expr.kind
{
expr = inner;
}
expr
}
/// Attempts to reparse as `Ty` (for diagnostic purposes).
pub fn to_ty(&self) -> Option<P<Ty>> {
let kind = match &self.kind {

18
compiler/rustc_ast_lowering/src/format.rs
View File

@ -34,7 +34,7 @@ fn flatten_format_args(mut fmt: Cow<'_, FormatArgs>) -> Cow<'_, FormatArgs> {
if let FormatArgsPiece::Placeholder(placeholder) = &fmt.template[i]
&& let FormatTrait::Display | FormatTrait::Debug = &placeholder.format_trait
&& let Ok(arg_index) = placeholder.argument.index
&& let arg = &fmt.arguments.all_args()[arg_index].expr
&& let arg = fmt.arguments.all_args()[arg_index].expr.peel_parens_and_refs()
&& let ExprKind::FormatArgs(_) = &arg.kind
// Check that this argument is not used by any other placeholders.
&& fmt.template.iter().enumerate().all(|(j, p)|
@ -54,9 +54,14 @@ fn flatten_format_args(mut fmt: Cow<'_, FormatArgs>) -> Cow<'_, FormatArgs> {
let args = fmt.arguments.all_args_mut();
let remaining_args = args.split_off(arg_index + 1);
let old_arg_offset = args.len();
let fmt2 = args.pop().unwrap().expr.into_inner(); // The inner FormatArgs.
let ExprKind::FormatArgs(fmt2) = fmt2.kind else { unreachable!() };
let mut fmt2 = fmt2.into_inner();
let mut fmt2 = &mut args.pop().unwrap().expr; // The inner FormatArgs.
let fmt2 = loop { // Unwrap the Expr to get to the FormatArgs.
match &mut fmt2.kind {
ExprKind::Paren(inner) | ExprKind::AddrOf(BorrowKind::Ref, _, inner) => fmt2 = inner,
ExprKind::FormatArgs(fmt2) => break fmt2,
_ => unreachable!(),
}
};
args.append(fmt2.arguments.all_args_mut());
let new_arg_offset = args.len();
@ -78,7 +83,7 @@ fn flatten_format_args(mut fmt: Cow<'_, FormatArgs>) -> Cow<'_, FormatArgs> {
let rest = fmt.template.split_off(i + 1);
fmt.template.pop(); // remove the placeholder for the nested fmt args.
for piece in fmt2.template {
for piece in fmt2.template.drain(..) {
match piece {
FormatArgsPiece::Literal(s) => fmt.template.push(FormatArgsPiece::Literal(s)),
FormatArgsPiece::Placeholder(mut p) => {
@ -119,7 +124,8 @@ fn inline_literals(mut fmt: Cow<'_, FormatArgs>) -> Cow<'_, FormatArgs> {
let FormatArgsPiece::Placeholder(placeholder) = &fmt.template[i] else { continue };
let Ok(arg_index) = placeholder.argument.index else { continue };
if let FormatTrait::Display = placeholder.format_trait
&& let ExprKind::Lit(lit) = fmt.arguments.all_args()[arg_index].expr.kind
&& let arg = fmt.arguments.all_args()[arg_index].expr.peel_parens_and_refs()
&& let ExprKind::Lit(lit) = arg.kind
&& let token::LitKind::Str | token::LitKind::StrRaw(_) = lit.kind
&& let Ok(LitKind::Str(s, _)) = LitKind::from_token_lit(lit)
{