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|
use super::{contains_return, BIND_INSTEAD_OF_MAP};
use clippy_utils::diagnostics::{multispan_sugg_with_applicability, span_lint_and_sugg, span_lint_and_then};
use clippy_utils::source::{snippet, snippet_with_macro_callsite};
use clippy_utils::ty::match_type;
use clippy_utils::{in_macro, match_qpath, method_calls, paths, remove_blocks, visitors::find_all_ret_expressions};
use if_chain::if_chain;
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_lint::LateContext;
use rustc_span::Span;
pub(crate) struct OptionAndThenSome;
impl BindInsteadOfMap for OptionAndThenSome {
const TYPE_NAME: &'static str = "Option";
const TYPE_QPATH: &'static [&'static str] = &paths::OPTION;
const BAD_METHOD_NAME: &'static str = "and_then";
const BAD_VARIANT_NAME: &'static str = "Some";
const BAD_VARIANT_QPATH: &'static [&'static str] = &paths::OPTION_SOME;
const GOOD_METHOD_NAME: &'static str = "map";
}
pub(crate) struct ResultAndThenOk;
impl BindInsteadOfMap for ResultAndThenOk {
const TYPE_NAME: &'static str = "Result";
const TYPE_QPATH: &'static [&'static str] = &paths::RESULT;
const BAD_METHOD_NAME: &'static str = "and_then";
const BAD_VARIANT_NAME: &'static str = "Ok";
const BAD_VARIANT_QPATH: &'static [&'static str] = &paths::RESULT_OK;
const GOOD_METHOD_NAME: &'static str = "map";
}
pub(crate) struct ResultOrElseErrInfo;
impl BindInsteadOfMap for ResultOrElseErrInfo {
const TYPE_NAME: &'static str = "Result";
const TYPE_QPATH: &'static [&'static str] = &paths::RESULT;
const BAD_METHOD_NAME: &'static str = "or_else";
const BAD_VARIANT_NAME: &'static str = "Err";
const BAD_VARIANT_QPATH: &'static [&'static str] = &paths::RESULT_ERR;
const GOOD_METHOD_NAME: &'static str = "map_err";
}
pub(crate) trait BindInsteadOfMap {
const TYPE_NAME: &'static str;
const TYPE_QPATH: &'static [&'static str];
const BAD_METHOD_NAME: &'static str;
const BAD_VARIANT_NAME: &'static str;
const BAD_VARIANT_QPATH: &'static [&'static str];
const GOOD_METHOD_NAME: &'static str;
fn no_op_msg() -> String {
format!(
"using `{}.{}({})`, which is a no-op",
Self::TYPE_NAME,
Self::BAD_METHOD_NAME,
Self::BAD_VARIANT_NAME
)
}
fn lint_msg() -> String {
format!(
"using `{}.{}(|x| {}(y))`, which is more succinctly expressed as `{}(|x| y)`",
Self::TYPE_NAME,
Self::BAD_METHOD_NAME,
Self::BAD_VARIANT_NAME,
Self::GOOD_METHOD_NAME
)
}
fn lint_closure_autofixable(
cx: &LateContext<'_>,
expr: &hir::Expr<'_>,
args: &[hir::Expr<'_>],
closure_expr: &hir::Expr<'_>,
closure_args_span: Span,
) -> bool {
if_chain! {
if let hir::ExprKind::Call(ref some_expr, ref some_args) = closure_expr.kind;
if let hir::ExprKind::Path(ref qpath) = some_expr.kind;
if match_qpath(qpath, Self::BAD_VARIANT_QPATH);
if some_args.len() == 1;
then {
let inner_expr = &some_args[0];
if contains_return(inner_expr) {
return false;
}
let some_inner_snip = if inner_expr.span.from_expansion() {
snippet_with_macro_callsite(cx, inner_expr.span, "_")
} else {
snippet(cx, inner_expr.span, "_")
};
let closure_args_snip = snippet(cx, closure_args_span, "..");
let option_snip = snippet(cx, args[0].span, "..");
let note = format!("{}.{}({} {})", option_snip, Self::GOOD_METHOD_NAME, closure_args_snip, some_inner_snip);
span_lint_and_sugg(
cx,
BIND_INSTEAD_OF_MAP,
expr.span,
Self::lint_msg().as_ref(),
"try this",
note,
Applicability::MachineApplicable,
);
true
} else {
false
}
}
}
fn lint_closure(cx: &LateContext<'_>, expr: &hir::Expr<'_>, closure_expr: &hir::Expr<'_>) -> bool {
let mut suggs = Vec::new();
let can_sugg: bool = find_all_ret_expressions(cx, closure_expr, |ret_expr| {
if_chain! {
if !in_macro(ret_expr.span);
if let hir::ExprKind::Call(ref func_path, ref args) = ret_expr.kind;
if let hir::ExprKind::Path(ref qpath) = func_path.kind;
if match_qpath(qpath, Self::BAD_VARIANT_QPATH);
if args.len() == 1;
if !contains_return(&args[0]);
then {
suggs.push((ret_expr.span, args[0].span.source_callsite()));
true
} else {
false
}
}
});
if can_sugg {
span_lint_and_then(cx, BIND_INSTEAD_OF_MAP, expr.span, Self::lint_msg().as_ref(), |diag| {
multispan_sugg_with_applicability(
diag,
"try this",
Applicability::MachineApplicable,
std::iter::once((*method_calls(expr, 1).2.get(0).unwrap(), Self::GOOD_METHOD_NAME.into())).chain(
suggs
.into_iter()
.map(|(span1, span2)| (span1, snippet(cx, span2, "_").into())),
),
)
});
}
can_sugg
}
/// Lint use of `_.and_then(|x| Some(y))` for `Option`s
fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, args: &[hir::Expr<'_>]) -> bool {
if !match_type(cx, cx.typeck_results().expr_ty(&args[0]), Self::TYPE_QPATH) {
return false;
}
match args[1].kind {
hir::ExprKind::Closure(_, _, body_id, closure_args_span, _) => {
let closure_body = cx.tcx.hir().body(body_id);
let closure_expr = remove_blocks(&closure_body.value);
if Self::lint_closure_autofixable(cx, expr, args, closure_expr, closure_args_span) {
true
} else {
Self::lint_closure(cx, expr, closure_expr)
}
},
// `_.and_then(Some)` case, which is no-op.
hir::ExprKind::Path(ref qpath) if match_qpath(qpath, Self::BAD_VARIANT_QPATH) => {
span_lint_and_sugg(
cx,
BIND_INSTEAD_OF_MAP,
expr.span,
Self::no_op_msg().as_ref(),
"use the expression directly",
snippet(cx, args[0].span, "..").into(),
Applicability::MachineApplicable,
);
true
},
_ => false,
}
}
}
|
