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Introduce hir::ExprKind::Let - Take 2

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This commit is contained in:
Caio 2021-08-08 11:49:13 -03:00
parent 80bff87c6f
commit b97d4c062b
56 changed files with 1065 additions and 691 deletions
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98
clippy_lints/src/loops/while_let_loop.rs
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@ -1,8 +1,9 @@
use super::WHILE_LET_LOOP;
use clippy_utils::diagnostics::span_lint_and_sugg;
use clippy_utils::higher;
use clippy_utils::source::snippet_with_applicability;
use rustc_errors::Applicability;
use rustc_hir::{Block, Expr, ExprKind, MatchSource, StmtKind};
use rustc_hir::{Block, Expr, ExprKind, MatchSource, Pat, StmtKind};
use rustc_lint::{LateContext, LintContext};
use rustc_middle::lint::in_external_macro;
@ -11,41 +12,25 @@ pub(super) fn check(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, loop_block: &'
let inner_stmt_expr = extract_expr_from_first_stmt(loop_block);
// or extract the first expression (if any) from the block
if let Some(inner) = inner_stmt_expr.or_else(|| extract_first_expr(loop_block)) {
if let ExprKind::Match(matchexpr, arms, ref source) = inner.kind {
// ensure "if let" compatible match structure
match *source {
MatchSource::Normal | MatchSource::IfLetDesugar { .. } => {
if arms.len() == 2
&& arms[0].guard.is_none()
&& arms[1].guard.is_none()
&& is_simple_break_expr(arms[1].body)
{
if in_external_macro(cx.sess(), expr.span) {
return;
}
if let Some(higher::IfLet {
let_pat,
let_expr,
if_else: Some(if_else),
..
}) = higher::IfLet::hir(inner)
{
if is_simple_break_expr(if_else) {
could_be_while_let(cx, expr, let_pat, let_expr);
}
}
// NOTE: we used to build a body here instead of using
// ellipsis, this was removed because:
// 1) it was ugly with big bodies;
// 2) it was not indented properly;
// 3) it wasn’t very smart (see #675).
let mut applicability = Applicability::HasPlaceholders;
span_lint_and_sugg(
cx,
WHILE_LET_LOOP,
expr.span,
"this loop could be written as a `while let` loop",
"try",
format!(
"while let {} = {} {{ .. }}",
snippet_with_applicability(cx, arms[0].pat.span, "..", &mut applicability),
snippet_with_applicability(cx, matchexpr.span, "..", &mut applicability),
),
applicability,
);
}
},
_ => (),
if let ExprKind::Match(ref matchexpr, ref arms, MatchSource::Normal) = inner.kind {
if arms.len() == 2
&& arms[0].guard.is_none()
&& arms[1].guard.is_none()
&& is_simple_break_expr(&arms[1].body)
{
could_be_while_let(cx, expr, &arms[0].pat, matchexpr);
}
}
}
@ -54,14 +39,12 @@ pub(super) fn check(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, loop_block: &'
/// If a block begins with a statement (possibly a `let` binding) and has an
/// expression, return it.
fn extract_expr_from_first_stmt<'tcx>(block: &Block<'tcx>) -> Option<&'tcx Expr<'tcx>> {
if block.stmts.is_empty() {
return None;
}
if let StmtKind::Local(local) = block.stmts[0].kind {
local.init //.map(|expr| expr)
} else {
None
if let Some(first_stmt) = block.stmts.get(0) {
if let StmtKind::Local(local) = first_stmt.kind {
return local.init;
}
}
None
}
/// If a block begins with an expression (with or without semicolon), return it.
@ -86,3 +69,34 @@ fn is_simple_break_expr(expr: &Expr<'_>) -> bool {
_ => false,
}
}
fn could_be_while_let<'tcx>(
cx: &LateContext<'tcx>,
expr: &'tcx Expr<'_>,
let_pat: &'tcx Pat<'_>,
let_expr: &'tcx Expr<'_>,
) {
if in_external_macro(cx.sess(), expr.span) {
return;
}
// NOTE: we used to build a body here instead of using
// ellipsis, this was removed because:
// 1) it was ugly with big bodies;
// 2) it was not indented properly;
// 3) it wasn’t very smart (see #675).
let mut applicability = Applicability::HasPlaceholders;
span_lint_and_sugg(
cx,
WHILE_LET_LOOP,
expr.span,
"this loop could be written as a `while let` loop",
"try",
format!(
"while let {} = {} {{ .. }}",
snippet_with_applicability(cx, let_pat.span, "..", &mut applicability),
snippet_with_applicability(cx, let_expr.span, "..", &mut applicability),
),
applicability,
);
}