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use clippy_utils::diagnostics::span_lint_and_help;
use clippy_utils::is_in_test_function;
use clippy_utils::ty::is_type_diagnostic_item;
use rustc_hir as hir;
use rustc_lint::LateContext;
use rustc_span::sym;
use super::EXPECT_USED;
/// lint use of `expect()` or `expect_err` for `Result` and `expect()` for `Option`.
pub(super) fn check(
cx: &LateContext<'_>,
expr: &hir::Expr<'_>,
recv: &hir::Expr<'_>,
is_err: bool,
allow_expect_in_tests: bool,
) {
let obj_ty = cx.typeck_results().expr_ty(recv).peel_refs();
let mess = if is_type_diagnostic_item(cx, obj_ty, sym::Option) && !is_err {
Some((EXPECT_USED, "an Option", "None", ""))
} else if is_type_diagnostic_item(cx, obj_ty, sym::Result) {
Some((EXPECT_USED, "a Result", if is_err { "Ok" } else { "Err" }, "an "))
} else {
None
};
let method = if is_err { "expect_err" } else { "expect" };
if allow_expect_in_tests && is_in_test_function(cx.tcx, expr.hir_id) {
return;
}
if let Some((lint, kind, none_value, none_prefix)) = mess {
span_lint_and_help(
cx,
lint,
expr.span,
&format!("used `{method}()` on `{kind}` value"),
None,
&format!("if this value is {none_prefix}`{none_value}`, it will panic"),
);
}
}
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