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needless_collect: Lint cases with type annotations

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Mateusz Gacek
2021-05-03 13:36:08 -07:00
parent 5e3160ca0b
commit b1faaaeb0c
3 changed files with 89 additions and 7 deletions
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23
clippy_lints/src/loops/needless_collect.rs
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@@ -7,9 +7,10 @@ use clippy_utils::{is_trait_method, path_to_local_id, paths};
use if_chain::if_chain;
use rustc_errors::Applicability;
use rustc_hir::intravisit::{walk_block, walk_expr, NestedVisitorMap, Visitor};
use rustc_hir::{Block, Expr, ExprKind, GenericArg, HirId, Local, Pat, PatKind, QPath, StmtKind};
use rustc_hir::{Block, Expr, ExprKind, GenericArg, GenericArgs, HirId, Local, Pat, PatKind, QPath, StmtKind, Ty};
use rustc_lint::LateContext;
use rustc_middle::hir::map::Map;
use rustc_span::symbol::{sym, Ident};
use rustc_span::{MultiSpan, Span};
@@ -58,18 +59,30 @@ fn check_needless_collect_direct_usage<'tcx>(expr: &'tcx Expr<'_>, cx: &LateCont
}
fn check_needless_collect_indirect_usage<'tcx>(expr: &'tcx Expr<'_>, cx: &LateContext<'tcx>) {
fn get_hir_id<'tcx>(ty: Option<&Ty<'tcx>>, method_args: Option<&GenericArgs<'tcx>>) -> Option<HirId> {
if let Some(ty) = ty {
return Some(ty.hir_id);
}
if let Some(generic_args) = method_args {
if let Some(GenericArg::Type(ref ty)) = generic_args.args.get(0) {
return Some(ty.hir_id);
}
}
None
}
if let ExprKind::Block(block, _) = expr.kind {
for stmt in block.stmts {
if_chain! {
if let StmtKind::Local(
Local { pat: Pat { hir_id: pat_id, kind: PatKind::Binding(_, _, ident, .. ), .. },
init: Some(init_expr), .. }
init: Some(init_expr), ty, .. }
) = stmt.kind;
if let ExprKind::MethodCall(method_name, collect_span, &[ref iter_source], ..) = init_expr.kind;
if method_name.ident.name == sym!(collect) && is_trait_method(cx, init_expr, sym::Iterator);
if let Some(generic_args) = method_name.args;
if let Some(GenericArg::Type(ref ty)) = generic_args.args.get(0);
if let ty = cx.typeck_results().node_type(ty.hir_id);
if let Some(hir_id) = get_hir_id(*ty, method_name.args);
if let ty = cx.typeck_results().node_type(hir_id);
if is_type_diagnostic_item(cx, ty, sym::vec_type) ||
is_type_diagnostic_item(cx, ty, sym::vecdeque_type) ||
match_type(cx, ty, &paths::LINKED_LIST);