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Split out match_wild_err_arm

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This commit is contained in:
Jason Newcomb 2022-02-06 16:08:05 -05:00
parent 2a70439ef0
commit dc75695e97
2 changed files with 55 additions and 49 deletions
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51
clippy_lints/src/matches/match_wild_err_arm.rs Normal file
View File

@ -0,0 +1,51 @@
use clippy_utils::diagnostics::span_lint_and_note;
use clippy_utils::macros::{is_panic, root_macro_call};
use clippy_utils::ty::is_type_diagnostic_item;
use clippy_utils::visitors::is_local_used;
use clippy_utils::{is_wild, peel_blocks_with_stmt};
use rustc_hir::{Arm, Expr, PatKind};
use rustc_lint::LateContext;
use rustc_span::symbol::{kw, sym};
use super::MATCH_WILD_ERR_ARM;
pub(crate) fn check<'tcx>(cx: &LateContext<'tcx>, ex: &Expr<'tcx>, arms: &[Arm<'tcx>]) {
let ex_ty = cx.typeck_results().expr_ty(ex).peel_refs();
if is_type_diagnostic_item(cx, ex_ty, sym::Result) {
for arm in arms {
if let PatKind::TupleStruct(ref path, inner, _) = arm.pat.kind {
let path_str = rustc_hir_pretty::to_string(rustc_hir_pretty::NO_ANN, |s| s.print_qpath(path, false));
if path_str == "Err" {
let mut matching_wild = inner.iter().any(is_wild);
let mut ident_bind_name = kw::Underscore;
if !matching_wild {
// Looking for unused bindings (i.e.: `_e`)
for pat in inner.iter() {
if let PatKind::Binding(_, id, ident, None) = pat.kind {
if ident.as_str().starts_with('_') && !is_local_used(cx, arm.body, id) {
ident_bind_name = ident.name;
matching_wild = true;
}
}
}
}
if_chain! {
if matching_wild;
if let Some(macro_call) = root_macro_call(peel_blocks_with_stmt(arm.body).span);
if is_panic(cx, macro_call.def_id);
then {
// `Err(_)` or `Err(_e)` arm with `panic!` found
span_lint_and_note(cx,
MATCH_WILD_ERR_ARM,
arm.pat.span,
&format!("`Err({})` matches all errors", ident_bind_name),
None,
"match each error separately or use the error output, or use `.except(msg)` if the error case is unreachable",
);
}
}
}
}
}
}
}

53
clippy_lints/src/matches/mod.rs
View File

@ -1,12 +1,7 @@
use clippy_utils::diagnostics::{
multispan_sugg, span_lint_and_help, span_lint_and_note, span_lint_and_sugg, span_lint_and_then,
};
use clippy_utils::macros::{is_panic, root_macro_call};
use clippy_utils::peel_blocks_with_stmt;
use clippy_utils::diagnostics::{multispan_sugg, span_lint_and_help, span_lint_and_sugg, span_lint_and_then};
use clippy_utils::source::{indent_of, snippet, snippet_block, snippet_opt, snippet_with_applicability};
use clippy_utils::sugg::Sugg;
use clippy_utils::ty::is_type_diagnostic_item;
use clippy_utils::visitors::is_local_used;
use clippy_utils::{
get_parent_expr, is_lang_ctor, is_refutable, is_wild, meets_msrv, msrvs, path_to_local_id, peel_blocks,
peel_hir_pat_refs, recurse_or_patterns, strip_pat_refs,
@ -24,11 +19,12 @@
use rustc_middle::ty::{self, VariantDef};
use rustc_semver::RustcVersion;
use rustc_session::{declare_tool_lint, impl_lint_pass};
use rustc_span::{sym, symbol::kw};
use rustc_span::sym;
mod match_bool;
mod match_like_matches;
mod match_same_arms;
mod match_wild_err_arm;
mod overlapping_arms;
mod redundant_pattern_match;
mod single_match;
@ -632,7 +628,7 @@ fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
single_match::check(cx, ex, arms, expr);
match_bool::check(cx, ex, arms, expr);
overlapping_arms::check(cx, ex, arms);
check_wild_err_arm(cx, ex, arms);
match_wild_err_arm::check(cx, ex, arms);
check_wild_enum_match(cx, ex, arms);
check_match_as_ref(cx, ex, arms, expr);
check_wild_in_or_pats(cx, arms);
@ -709,47 +705,6 @@ fn check_pat(&mut self, cx: &LateContext<'tcx>, pat: &'tcx Pat<'_>) {
extract_msrv_attr!(LateContext);
}
fn check_wild_err_arm<'tcx>(cx: &LateContext<'tcx>, ex: &Expr<'tcx>, arms: &[Arm<'tcx>]) {
let ex_ty = cx.typeck_results().expr_ty(ex).peel_refs();
if is_type_diagnostic_item(cx, ex_ty, sym::Result) {
for arm in arms {
if let PatKind::TupleStruct(ref path, inner, _) = arm.pat.kind {
let path_str = rustc_hir_pretty::to_string(rustc_hir_pretty::NO_ANN, |s| s.print_qpath(path, false));
if path_str == "Err" {
let mut matching_wild = inner.iter().any(is_wild);
let mut ident_bind_name = kw::Underscore;
if !matching_wild {
// Looking for unused bindings (i.e.: `_e`)
for pat in inner.iter() {
if let PatKind::Binding(_, id, ident, None) = pat.kind {
if ident.as_str().starts_with('_') && !is_local_used(cx, arm.body, id) {
ident_bind_name = ident.name;
matching_wild = true;
}
}
}
}
if_chain! {
if matching_wild;
if let Some(macro_call) = root_macro_call(peel_blocks_with_stmt(arm.body).span);
if is_panic(cx, macro_call.def_id);
then {
// `Err(_)` or `Err(_e)` arm with `panic!` found
span_lint_and_note(cx,
MATCH_WILD_ERR_ARM,
arm.pat.span,
&format!("`Err({})` matches all errors", ident_bind_name),
None,
"match each error separately or use the error output, or use `.except(msg)` if the error case is unreachable",
);
}
}
}
}
}
}
}
enum CommonPrefixSearcher<'a> {
None,
Path(&'a [PathSegment<'a>]),