From 4873ebee4ca98805ba4a404c7bbeae98639dc91c Mon Sep 17 00:00:00 2001
From: Cameron Steffen <cam.steffen94@gmail.com>
Date: Tue, 21 Sep 2021 00:56:45 -0500
Subject: [PATCH] Use ZST for fmt unsafety
This allows the format_args! macro to keep the pre-expansion code out of
the unsafe block without doing gymnastics with nested `match`
expressions. This reduces codegen.
---
clippy_utils/src/higher.rs | 35 +++++++++++++++--------------------
1 file changed, 15 insertions(+), 20 deletions(-)
diff --git a/clippy_utils/src/higher.rs b/clippy_utils/src/higher.rs
index 05a4a014319..ff55ff35a13 100644
--- a/clippy_utils/src/higher.rs
+++ b/clippy_utils/src/higher.rs
@@ -524,28 +524,12 @@ impl FormatArgsExpn<'tcx> {
if let ExpnKind::Macro(_, name) = expr.span.ctxt().outer_expn_data().kind;
let name = name.as_str();
if name.ends_with("format_args") || name.ends_with("format_args_nl");
-
- if let ExprKind::Match(inner_match, [arm], _) = expr.kind;
-
- // `match match`, if you will
- if let ExprKind::Match(args, [inner_arm], _) = inner_match.kind;
- if let ExprKind::Tup(value_args) = args.kind;
- if let Some(value_args) = value_args
- .iter()
- .map(|e| match e.kind {
- ExprKind::AddrOf(_, _, e) => Some(e),
- _ => None,
- })
- .collect();
- if let ExprKind::Array(args) = inner_arm.body.kind;
-
- if let ExprKind::Block(Block { stmts: [], expr: Some(expr), .. }, _) = arm.body.kind;
- if let ExprKind::Call(_, call_args) = expr.kind;
- if let Some((strs_ref, fmt_expr)) = match call_args {
+ if let ExprKind::Call(_, args) = expr.kind;
+ if let Some((strs_ref, args, fmt_expr)) = match args {
// Arguments::new_v1
- [strs_ref, _] => Some((strs_ref, None)),
+ [strs_ref, args] => Some((strs_ref, args, None)),
// Arguments::new_v1_formatted
- [strs_ref, _, fmt_expr] => Some((strs_ref, Some(fmt_expr))),
+ [strs_ref, args, fmt_expr, _unsafe_arg] => Some((strs_ref, args, Some(fmt_expr))),
_ => None,
};
if let ExprKind::AddrOf(BorrowKind::Ref, _, strs_arr) = strs_ref.kind;
@@ -561,6 +545,17 @@ impl FormatArgsExpn<'tcx> {
None
})
.collect();
+ if let ExprKind::AddrOf(BorrowKind::Ref, _, args) = args.kind;
+ if let ExprKind::Match(args, [arm], _) = args.kind;
+ if let ExprKind::Tup(value_args) = args.kind;
+ if let Some(value_args) = value_args
+ .iter()
+ .map(|e| match e.kind {
+ ExprKind::AddrOf(_, _, e) => Some(e),
+ _ => None,
+ })
+ .collect();
+ if let ExprKind::Array(args) = arm.body.kind;
then {
Some(FormatArgsExpn {
format_string_span: strs_ref.span,