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|
use clippy_utils::diagnostics::span_lint_and_sugg;
use clippy_utils::macros::{root_macro_call_first_node, FormatArgsExpn};
use clippy_utils::source::snippet_with_applicability;
use clippy_utils::ty::is_type_diagnostic_item;
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_lint::LateContext;
use rustc_middle::ty;
use rustc_span::source_map::Span;
use rustc_span::symbol::sym;
use std::borrow::Cow;
use super::EXPECT_FUN_CALL;
/// Checks for the `EXPECT_FUN_CALL` lint.
#[allow(clippy::too_many_lines)]
pub(super) fn check<'tcx>(
cx: &LateContext<'tcx>,
expr: &hir::Expr<'_>,
method_span: Span,
name: &str,
receiver: &'tcx hir::Expr<'tcx>,
args: &'tcx [hir::Expr<'tcx>],
) {
// Strip `&`, `as_ref()` and `as_str()` off `arg` until we're left with either a `String` or
// `&str`
fn get_arg_root<'a>(cx: &LateContext<'_>, arg: &'a hir::Expr<'a>) -> &'a hir::Expr<'a> {
let mut arg_root = arg;
loop {
arg_root = match &arg_root.kind {
hir::ExprKind::AddrOf(hir::BorrowKind::Ref, _, expr) => expr,
hir::ExprKind::MethodCall(method_name, receiver, [], ..) => {
if (method_name.ident.name == sym::as_str || method_name.ident.name == sym::as_ref) && {
let arg_type = cx.typeck_results().expr_ty(receiver);
let base_type = arg_type.peel_refs();
*base_type.kind() == ty::Str || is_type_diagnostic_item(cx, base_type, sym::String)
} {
receiver
} else {
break;
}
},
_ => break,
};
}
arg_root
}
// Only `&'static str` or `String` can be used directly in the `panic!`. Other types should be
// converted to string.
fn requires_to_string(cx: &LateContext<'_>, arg: &hir::Expr<'_>) -> bool {
let arg_ty = cx.typeck_results().expr_ty(arg);
if is_type_diagnostic_item(cx, arg_ty, sym::String) {
return false;
}
if let ty::Ref(_, ty, ..) = arg_ty.kind() {
if *ty.kind() == ty::Str && can_be_static_str(cx, arg) {
return false;
}
};
true
}
// Check if an expression could have type `&'static str`, knowing that it
// has type `&str` for some lifetime.
fn can_be_static_str(cx: &LateContext<'_>, arg: &hir::Expr<'_>) -> bool {
match arg.kind {
hir::ExprKind::Lit(_) => true,
hir::ExprKind::Call(fun, _) => {
if let hir::ExprKind::Path(ref p) = fun.kind {
match cx.qpath_res(p, fun.hir_id) {
hir::def::Res::Def(hir::def::DefKind::Fn | hir::def::DefKind::AssocFn, def_id) => matches!(
cx.tcx.fn_sig(def_id).output().skip_binder().kind(),
ty::Ref(re, ..) if re.is_static(),
),
_ => false,
}
} else {
false
}
},
hir::ExprKind::MethodCall(..) => {
cx.typeck_results()
.type_dependent_def_id(arg.hir_id)
.map_or(false, |method_id| {
matches!(
cx.tcx.fn_sig(method_id).output().skip_binder().kind(),
ty::Ref(re, ..) if re.is_static()
)
})
},
hir::ExprKind::Path(ref p) => matches!(
cx.qpath_res(p, arg.hir_id),
hir::def::Res::Def(hir::def::DefKind::Const | hir::def::DefKind::Static(_), _)
),
_ => false,
}
}
fn is_call(node: &hir::ExprKind<'_>) -> bool {
match node {
hir::ExprKind::AddrOf(hir::BorrowKind::Ref, _, expr) => {
is_call(&expr.kind)
},
hir::ExprKind::Call(..)
| hir::ExprKind::MethodCall(..)
// These variants are debatable or require further examination
| hir::ExprKind::If(..)
| hir::ExprKind::Match(..)
| hir::ExprKind::Block{ .. } => true,
_ => false,
}
}
if args.len() != 1 || name != "expect" || !is_call(&args[0].kind) {
return;
}
let receiver_type = cx.typeck_results().expr_ty_adjusted(receiver);
let closure_args = if is_type_diagnostic_item(cx, receiver_type, sym::Option) {
"||"
} else if is_type_diagnostic_item(cx, receiver_type, sym::Result) {
"|_|"
} else {
return;
};
let arg_root = get_arg_root(cx, &args[0]);
let span_replace_word = method_span.with_hi(expr.span.hi());
let mut applicability = Applicability::MachineApplicable;
//Special handling for `format!` as arg_root
if let Some(macro_call) = root_macro_call_first_node(cx, arg_root) {
if !cx.tcx.is_diagnostic_item(sym::format_macro, macro_call.def_id) {
return;
}
let Some(format_args) = FormatArgsExpn::find_nested(cx, arg_root, macro_call.expn) else { return };
let span = format_args.inputs_span();
let sugg = snippet_with_applicability(cx, span, "..", &mut applicability);
span_lint_and_sugg(
cx,
EXPECT_FUN_CALL,
span_replace_word,
&format!("use of `{}` followed by a function call", name),
"try this",
format!("unwrap_or_else({} panic!({}))", closure_args, sugg),
applicability,
);
return;
}
let mut arg_root_snippet: Cow<'_, _> = snippet_with_applicability(cx, arg_root.span, "..", &mut applicability);
if requires_to_string(cx, arg_root) {
arg_root_snippet.to_mut().push_str(".to_string()");
}
span_lint_and_sugg(
cx,
EXPECT_FUN_CALL,
span_replace_word,
&format!("use of `{}` followed by a function call", name),
"try this",
format!(
"unwrap_or_else({} {{ panic!(\"{{}}\", {}) }})",
closure_args, arg_root_snippet
),
applicability,
);
}
|
