Files
rust/clippy_lints/src/methods/manual_is_variant_and.rs

118 lines
4.3 KiB
Rust

use clippy_utils::diagnostics::span_lint_and_sugg;
use clippy_utils::get_parent_expr;
use clippy_utils::msrvs::{self, Msrv};
use clippy_utils::source::{snippet, snippet_opt};
use clippy_utils::ty::is_type_diagnostic_item;
use rustc_errors::Applicability;
use rustc_hir::def::{CtorKind, CtorOf, DefKind, Res};
use rustc_hir::{BinOpKind, Expr, ExprKind, QPath};
use rustc_lint::LateContext;
use rustc_middle::ty;
use rustc_span::{BytePos, Span, sym};
use super::MANUAL_IS_VARIANT_AND;
pub(super) fn check(
cx: &LateContext<'_>,
expr: &Expr<'_>,
map_recv: &Expr<'_>,
map_arg: &Expr<'_>,
map_span: Span,
msrv: Msrv,
) {
// Don't lint if:
// 1. the `expr` is generated by a macro
if expr.span.from_expansion() {
return;
}
// 2. the caller of `map()` is neither `Option` nor `Result`
let is_option = is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(map_recv), sym::Option);
let is_result = is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(map_recv), sym::Result);
if !is_option && !is_result {
return;
}
// 3. the caller of `unwrap_or_default` is neither `Option<bool>` nor `Result<bool, _>`
if !cx.typeck_results().expr_ty(expr).is_bool() {
return;
}
// 4. msrv doesn't meet `OPTION_RESULT_IS_VARIANT_AND`
if !msrv.meets(cx, msrvs::OPTION_RESULT_IS_VARIANT_AND) {
return;
}
let lint_msg = if is_option {
"called `map(<f>).unwrap_or_default()` on an `Option` value"
} else {
"called `map(<f>).unwrap_or_default()` on a `Result` value"
};
let suggestion = if is_option { "is_some_and" } else { "is_ok_and" };
span_lint_and_sugg(
cx,
MANUAL_IS_VARIANT_AND,
expr.span.with_lo(map_span.lo()),
lint_msg,
"use",
format!("{}({})", suggestion, snippet(cx, map_arg.span, "..")),
Applicability::MachineApplicable,
);
}
fn emit_lint(cx: &LateContext<'_>, op: BinOpKind, parent: &Expr<'_>, method_span: Span, is_option: bool) {
if let Some(before_map_snippet) = snippet_opt(cx, parent.span.with_hi(method_span.lo()))
&& let Some(after_map_snippet) = snippet_opt(cx, method_span.with_lo(method_span.lo() + BytePos(3)))
{
span_lint_and_sugg(
cx,
MANUAL_IS_VARIANT_AND,
parent.span,
format!(
"called `.map() {}= {}()`",
if op == BinOpKind::Eq { '=' } else { '!' },
if is_option { "Some" } else { "Ok" },
),
"use",
if is_option && op == BinOpKind::Ne {
format!("{before_map_snippet}is_none_or{after_map_snippet}",)
} else {
format!(
"{}{before_map_snippet}{}{after_map_snippet}",
if op == BinOpKind::Eq { "" } else { "!" },
if is_option { "is_some_and" } else { "is_ok_and" },
)
},
Applicability::MachineApplicable,
);
}
}
pub(super) fn check_map(cx: &LateContext<'_>, expr: &Expr<'_>) {
if let Some(parent_expr) = get_parent_expr(cx, expr)
&& let ExprKind::Binary(op, left, right) = parent_expr.kind
&& matches!(op.node, BinOpKind::Eq | BinOpKind::Ne)
&& op.span.eq_ctxt(expr.span)
{
// Check `left` and `right` expression in any order, and for `Option` and `Result`
for (expr1, expr2) in [(left, right), (right, left)] {
for item in [sym::Option, sym::Result] {
if let ExprKind::Call(call, ..) = expr1.kind
&& let ExprKind::Path(QPath::Resolved(_, path)) = call.kind
&& let Res::Def(DefKind::Ctor(CtorOf::Variant, CtorKind::Fn), _) = path.res
&& let ty = cx.typeck_results().expr_ty(expr1)
&& let ty::Adt(adt, args) = ty.kind()
&& cx.tcx.is_diagnostic_item(item, adt.did())
&& args.type_at(0).is_bool()
&& let ExprKind::MethodCall(_, recv, _, span) = expr2.kind
&& is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(recv), item)
{
return emit_lint(cx, op.node, parent_expr, span, item == sym::Option);
}
}
}
}
}