83 lines
2.6 KiB
Rust
83 lines
2.6 KiB
Rust
use super::utils::derefs_to_slice;
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use clippy_utils::diagnostics::span_lint_and_sugg;
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use clippy_utils::get_parent_expr;
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use clippy_utils::source::snippet_with_applicability;
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use clippy_utils::ty::is_type_diagnostic_item;
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use if_chain::if_chain;
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use rustc_errors::Applicability;
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use rustc_hir as hir;
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use rustc_lint::LateContext;
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use rustc_span::sym;
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use super::GET_UNWRAP;
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pub(super) fn check<'tcx>(
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cx: &LateContext<'tcx>,
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expr: &hir::Expr<'_>,
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recv: &'tcx hir::Expr<'tcx>,
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get_arg: &'tcx hir::Expr<'_>,
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is_mut: bool,
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) {
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// Note: we don't want to lint `get_mut().unwrap` for `HashMap` or `BTreeMap`,
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// because they do not implement `IndexMut`
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let mut applicability = Applicability::MachineApplicable;
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let expr_ty = cx.typeck_results().expr_ty(recv);
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let get_args_str = snippet_with_applicability(cx, get_arg.span, "..", &mut applicability);
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let mut needs_ref;
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let caller_type = if derefs_to_slice(cx, recv, expr_ty).is_some() {
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needs_ref = get_args_str.parse::<usize>().is_ok();
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"slice"
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} else if is_type_diagnostic_item(cx, expr_ty, sym::Vec) {
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needs_ref = get_args_str.parse::<usize>().is_ok();
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"Vec"
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} else if is_type_diagnostic_item(cx, expr_ty, sym::VecDeque) {
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needs_ref = get_args_str.parse::<usize>().is_ok();
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"VecDeque"
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} else if !is_mut && is_type_diagnostic_item(cx, expr_ty, sym::HashMap) {
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needs_ref = true;
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"HashMap"
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} else if !is_mut && is_type_diagnostic_item(cx, expr_ty, sym::BTreeMap) {
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needs_ref = true;
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"BTreeMap"
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} else {
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return; // caller is not a type that we want to lint
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};
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let mut span = expr.span;
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// Handle the case where the result is immediately dereferenced
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// by not requiring ref and pulling the dereference into the
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// suggestion.
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if_chain! {
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if needs_ref;
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if let Some(parent) = get_parent_expr(cx, expr);
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if let hir::ExprKind::Unary(hir::UnOp::Deref, _) = parent.kind;
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then {
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needs_ref = false;
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span = parent.span;
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}
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}
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let mut_str = if is_mut { "_mut" } else { "" };
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let borrow_str = if !needs_ref {
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""
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} else if is_mut {
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"&mut "
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} else {
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"&"
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};
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span_lint_and_sugg(
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cx,
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GET_UNWRAP,
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span,
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&format!("called `.get{mut_str}().unwrap()` on a {caller_type}. Using `[]` is more clear and more concise"),
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"try this",
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format!(
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"{borrow_str}{}[{get_args_str}]",
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snippet_with_applicability(cx, recv.span, "..", &mut applicability)
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),
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applicability,
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);
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}
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