rust/clippy_lints/src/items_after_test_module.rs

110 lines
3.8 KiB
Rust

use clippy_utils::diagnostics::span_lint_hir_and_then;
use clippy_utils::source::snippet_opt;
use clippy_utils::{fulfill_or_allowed, is_cfg_test, is_from_proc_macro};
use rustc_errors::{Applicability, SuggestionStyle};
use rustc_hir::{HirId, Item, ItemKind, Mod};
use rustc_lint::{LateContext, LateLintPass};
use rustc_session::declare_lint_pass;
use rustc_span::hygiene::AstPass;
use rustc_span::{sym, ExpnKind};
declare_clippy_lint! {
/// ### What it does
/// Triggers if an item is declared after the testing module marked with `#[cfg(test)]`.
/// ### Why is this bad?
/// Having items declared after the testing module is confusing and may lead to bad test coverage.
/// ### Example
/// ```no_run
/// #[cfg(test)]
/// mod tests {
/// // [...]
/// }
///
/// fn my_function() {
/// // [...]
/// }
/// ```
/// Use instead:
/// ```no_run
/// fn my_function() {
/// // [...]
/// }
///
/// #[cfg(test)]
/// mod tests {
/// // [...]
/// }
/// ```
#[clippy::version = "1.71.0"]
pub ITEMS_AFTER_TEST_MODULE,
style,
"An item was found after the testing module `tests`"
}
declare_lint_pass!(ItemsAfterTestModule => [ITEMS_AFTER_TEST_MODULE]);
fn cfg_test_module<'tcx>(cx: &LateContext<'tcx>, item: &Item<'tcx>) -> bool {
if let ItemKind::Mod(test_mod) = item.kind
&& item.span.hi() == test_mod.spans.inner_span.hi()
&& is_cfg_test(cx.tcx, item.hir_id())
&& !item.span.from_expansion()
&& !is_from_proc_macro(cx, item)
{
true
} else {
false
}
}
impl LateLintPass<'_> for ItemsAfterTestModule {
fn check_mod(&mut self, cx: &LateContext<'_>, module: &Mod<'_>, _: HirId) {
let mut items = module.item_ids.iter().map(|&id| cx.tcx.hir().item(id));
let Some((mod_pos, test_mod)) = items.by_ref().enumerate().find(|(_, item)| cfg_test_module(cx, item)) else {
return;
};
let after: Vec<_> = items
.filter(|item| {
// Ignore the generated test main function
!(item.ident.name == sym::main
&& item.span.ctxt().outer_expn_data().kind == ExpnKind::AstPass(AstPass::TestHarness))
})
.collect();
if let Some(last) = after.last()
&& after.iter().all(|&item| {
!matches!(item.kind, ItemKind::Mod(_)) && !item.span.from_expansion() && !is_from_proc_macro(cx, item)
})
&& !fulfill_or_allowed(cx, ITEMS_AFTER_TEST_MODULE, after.iter().map(|item| item.hir_id()))
{
let def_spans: Vec<_> = std::iter::once(test_mod.owner_id)
.chain(after.iter().map(|item| item.owner_id))
.map(|id| cx.tcx.def_span(id))
.collect();
span_lint_hir_and_then(
cx,
ITEMS_AFTER_TEST_MODULE,
test_mod.hir_id(),
def_spans,
"items after a test module",
|diag| {
if let Some(prev) = mod_pos.checked_sub(1)
&& let prev = cx.tcx.hir().item(module.item_ids[prev])
&& let items_span = last.span.with_lo(test_mod.span.hi())
&& let Some(items) = snippet_opt(cx, items_span)
{
diag.multipart_suggestion_with_style(
"move the items to before the test module was defined",
vec![(prev.span.shrink_to_hi(), items), (items_span, String::new())],
Applicability::MachineApplicable,
SuggestionStyle::HideCodeAlways,
);
}
},
);
}
}
}