feat(unnecessary_fold): lint on folds with Add::add/Mul::mul
#16124
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| // - the final expression in the body of a function with a simple return type | ||
| if let hir::Node::Block(block) = parent | ||
| && let mut parents = cx.tcx.hir_parent_iter(block.hir_id).map(|(_, def_id)| def_id) | ||
| && let Some(hir::Node::Expr(_)) = parents.next() | ||
| && let Some(hir::Node::Item(enclosing_item)) = parents.next() | ||
| && let hir::ItemKind::Fn { sig, .. } = enclosing_item.kind | ||
| && let hir::FnRetTy::Return(fn_return_ty) = sig.decl.output | ||
| && matches!(fn_return_ty.kind, hir::TyKind::Path(..)) | ||
| { | ||
| return false; | ||
| } |
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This and the previous checks are a subset of what using expr_use_ctxt would get you. You want something like:
if let Some(use_cx) = expr_use_ctxt(cx, expr)
&& use_cx.is_same_ctxt
&& let Some(ty) = use_cx.use_node(cx).defined_ty(cx)
{
// check ty
}There was a problem hiding this comment.
Ah, thanks for the tip! Changed
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… `fold`s with `Add::add`/`Mul::mul`
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| // - the final expression in the body of a function with a simple return type | ||
| (ExprUseNode::Return(_), DefinedTy::Mir { ty: fn_return_ty, .. }) | ||
| if fn_return_ty.skip_binder().is_simple_text() => |
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What is this supposed to be checking for? The return type of a function must be a fully defined type.
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What is this supposed to be checking for?
Opaque types (like impl Add/Mul, see {add,mul}_turbofish_necessary), and generic types with trait bounds (something like fn sum<T: Add>(ts: &[T]) -> T), it seems
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Can you change it to checking for opaque types then. Ty::walk will get you all the types you need to check.
The type of generic parameters can't be changed by inference so you can ignore those.
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Resurrects #13475
changelog: [
unnecessary_fold]: lint onfolds withAdd::add/Mul::mul