Auto merge of #11135 - smoelius:unwrap_or_else_default-fp, r=Centri3

Fix `unwrap_or_else_default` false positive

This PR fixes a false positive in the handling of `unwrap_or_else` with a default value when the value is needed for type inference.

An easy example to exhibit the false positive is the following:
```rust
    let option = None;
    option.unwrap_or_else(Vec::new).push(1);
```
The following code would not compile, because the fact that the value is a `Vec` has been lost:
```rust
    let option = None;
    option.unwrap_or_default().push(1);
```
The fix is to:
- implement a heuristic to tell whether an expression's type can be determined purely from its subexpressions, and the arguments and locals they use;
- apply the heuristic to `unwrap_or_else`'s receiver.

The heuristic returns false when applied to `option` in the above example, but it returns true when applied to `option` in either of the following examples:
```rust
    let option: Option<Vec<u64>> = None;
    option.unwrap_or_else(Vec::new).push(1);
```
```rust
    let option = None::<Vec<u64>>;
    option.unwrap_or_else(Vec::new).push(1);
```

(Aside: https://github.com/rust-lang/rust-clippy/pull/10120 unfairly contained multiple changes in one PR. I am trying to break that PR up into smaller pieces.)

---

changelog: FP: [`unwrap_or_else_default`]: No longer lints if the default value is needed for type inference

clippy_lints/src/methods/unwrap_or_else_default.rs

@@ -4,7 +4,7 @@ use super::UNWRAP_OR_ELSE_DEFAULT;
 use clippy_utils::diagnostics::span_lint_and_sugg;
 use clippy_utils::is_default_equivalent_call;
 use clippy_utils::source::snippet_with_applicability;
-use clippy_utils::ty::is_type_diagnostic_item;
+use clippy_utils::ty::{expr_type_is_certain, is_type_diagnostic_item};
 use rustc_ast::ast::LitKind;
 use rustc_errors::Applicability;
 use rustc_hir as hir;
@@ -17,6 +17,10 @@ pub(super) fn check<'tcx>(
     recv: &'tcx hir::Expr<'_>,
     u_arg: &'tcx hir::Expr<'_>,
 ) {
+    if !expr_type_is_certain(cx, recv) {
+        return;
+    }
+
     // something.unwrap_or_else(Default::default)
     // ^^^^^^^^^- recv          ^^^^^^^^^^^^^^^^- u_arg
     // ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^- expr

clippy_utils/src/ty.rs

@@ -28,6 +28,9 @@ use std::iter;
 
 use crate::{match_def_path, path_res, paths};
 
+mod type_certainty;
+pub use type_certainty::expr_type_is_certain;
+
 /// Checks if the given type implements copy.
 pub fn is_copy<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
     ty.is_copy_modulo_regions(cx.tcx, cx.param_env)

clippy_utils/src/ty/type_certainty/certainty.rs

@@ -0,0 +1,122 @@
+use rustc_hir::def_id::DefId;
+use std::fmt::Debug;
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum Certainty {
+    /// Determining the type requires contextual information.
+    Uncertain,
+
+    /// The type can be determined purely from subexpressions. If the argument is `Some(..)`, the
+    /// specific `DefId` is known. Such arguments are needed to handle path segments whose `res` is
+    /// `Res::Err`.
+    Certain(Option<DefId>),
+
+    /// The heuristic believes that more than one `DefId` applies to a type---this is a bug.
+    Contradiction,
+}
+
+pub trait Meet {
+    fn meet(self, other: Self) -> Self;
+}
+
+pub trait TryJoin: Sized {
+    fn try_join(self, other: Self) -> Option<Self>;
+}
+
+impl Meet for Option<DefId> {
+    fn meet(self, other: Self) -> Self {
+        match (self, other) {
+            (None, _) | (_, None) => None,
+            (Some(lhs), Some(rhs)) => (lhs == rhs).then_some(lhs),
+        }
+    }
+}
+
+impl TryJoin for Option<DefId> {
+    fn try_join(self, other: Self) -> Option<Self> {
+        match (self, other) {
+            (Some(lhs), Some(rhs)) => (lhs == rhs).then_some(Some(lhs)),
+            (Some(def_id), _) | (_, Some(def_id)) => Some(Some(def_id)),
+            (None, None) => Some(None),
+        }
+    }
+}
+
+impl Meet for Certainty {
+    fn meet(self, other: Self) -> Self {
+        match (self, other) {
+            (Certainty::Uncertain, _) | (_, Certainty::Uncertain) => Certainty::Uncertain,
+            (Certainty::Certain(lhs), Certainty::Certain(rhs)) => Certainty::Certain(lhs.meet(rhs)),
+            (Certainty::Certain(inner), _) | (_, Certainty::Certain(inner)) => Certainty::Certain(inner),
+            (Certainty::Contradiction, Certainty::Contradiction) => Certainty::Contradiction,
+        }
+    }
+}
+
+impl Certainty {
+    /// Join two `Certainty`s preserving their `DefId`s (if any). Generally speaking, this method
+    /// should be used only when `self` and `other` refer directly to types. Otherwise,
+    /// `join_clearing_def_ids` should be used.
+    pub fn join(self, other: Self) -> Self {
+        match (self, other) {
+            (Certainty::Contradiction, _) | (_, Certainty::Contradiction) => Certainty::Contradiction,
+
+            (Certainty::Certain(lhs), Certainty::Certain(rhs)) => {
+                if let Some(inner) = lhs.try_join(rhs) {
+                    Certainty::Certain(inner)
+                } else {
+                    debug_assert!(false, "Contradiction with {lhs:?} and {rhs:?}");
+                    Certainty::Contradiction
+                }
+            },
+
+            (Certainty::Certain(inner), _) | (_, Certainty::Certain(inner)) => Certainty::Certain(inner),
+
+            (Certainty::Uncertain, Certainty::Uncertain) => Certainty::Uncertain,
+        }
+    }
+
+    /// Join two `Certainty`s after clearing their `DefId`s. This method should be used when `self`
+    /// or `other` do not necessarily refer to types, e.g., when they are aggregations of other
+    /// `Certainty`s.
+    pub fn join_clearing_def_ids(self, other: Self) -> Self {
+        self.clear_def_id().join(other.clear_def_id())
+    }
+
+    pub fn clear_def_id(self) -> Certainty {
+        if matches!(self, Certainty::Certain(_)) {
+            Certainty::Certain(None)
+        } else {
+            self
+        }
+    }
+
+    pub fn with_def_id(self, def_id: DefId) -> Certainty {
+        if matches!(self, Certainty::Certain(_)) {
+            Certainty::Certain(Some(def_id))
+        } else {
+            self
+        }
+    }
+
+    pub fn to_def_id(self) -> Option<DefId> {
+        match self {
+            Certainty::Certain(inner) => inner,
+            _ => None,
+        }
+    }
+
+    pub fn is_certain(self) -> bool {
+        matches!(self, Self::Certain(_))
+    }
+}
+
+/// Think: `iter.all(/* is certain */)`
+pub fn meet(iter: impl Iterator<Item = Certainty>) -> Certainty {
+    iter.fold(Certainty::Certain(None), Certainty::meet)
+}
+
+/// Think: `iter.any(/* is certain */)`
+pub fn join(iter: impl Iterator<Item = Certainty>) -> Certainty {
+    iter.fold(Certainty::Uncertain, Certainty::join)
+}

clippy_utils/src/ty/type_certainty/mod.rs

@@ -0,0 +1,315 @@
+//! A heuristic to tell whether an expression's type can be determined purely from its
+//! subexpressions, and the arguments and locals they use. Put another way, `expr_type_is_certain`
+//! tries to tell whether an expression's type can be determined without appeal to the surrounding
+//! context.
+//!
+//! This is, in some sense, a counterpart to `let_unit_value`'s `expr_needs_inferred_result`.
+//! Intuitively, that function determines whether an expression's type is needed for type inference,
+//! whereas `expr_type_is_certain` determines whether type inference is needed for an expression's
+//! type.
+//!
+//! As a heuristic, `expr_type_is_certain` may produce false negatives, but a false positive should
+//! be considered a bug.
+
+use crate::def_path_res;
+use rustc_hir::def::Res;
+use rustc_hir::def_id::DefId;
+use rustc_hir::intravisit::{walk_qpath, walk_ty, Visitor};
+use rustc_hir::{self as hir, Expr, ExprKind, GenericArgs, HirId, Node, PathSegment, QPath, TyKind};
+use rustc_lint::LateContext;
+use rustc_middle::ty::{self, AdtDef, GenericArgKind, Ty};
+use rustc_span::{Span, Symbol};
+
+mod certainty;
+use certainty::{join, meet, Certainty, Meet};
+
+pub fn expr_type_is_certain(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
+    expr_type_certainty(cx, expr).is_certain()
+}
+
+fn expr_type_certainty(cx: &LateContext<'_>, expr: &Expr<'_>) -> Certainty {
+    let certainty = match &expr.kind {
+        ExprKind::Unary(_, expr)
+        | ExprKind::Field(expr, _)
+        | ExprKind::Index(expr, _)
+        | ExprKind::AddrOf(_, _, expr) => expr_type_certainty(cx, expr),
+
+        ExprKind::Array(exprs) => join(exprs.iter().map(|expr| expr_type_certainty(cx, expr))),
+
+        ExprKind::Call(callee, args) => {
+            let lhs = expr_type_certainty(cx, callee);
+            let rhs = if type_is_inferrable_from_arguments(cx, expr) {
+                meet(args.iter().map(|arg| expr_type_certainty(cx, arg)))
+            } else {
+                Certainty::Uncertain
+            };
+            lhs.join_clearing_def_ids(rhs)
+        },
+
+        ExprKind::MethodCall(method, receiver, args, _) => {
+            let mut receiver_type_certainty = expr_type_certainty(cx, receiver);
+            // Even if `receiver_type_certainty` is `Certain(Some(..))`, the `Self` type in the method
+            // identified by `type_dependent_def_id(..)` can differ. This can happen as a result of a `deref`,
+            // for example. So update the `DefId` in `receiver_type_certainty` (if any).
+            if let Some(method_def_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id)
+                && let Some(self_ty_def_id) = adt_def_id(self_ty(cx, method_def_id))
+            {
+                receiver_type_certainty = receiver_type_certainty.with_def_id(self_ty_def_id);
+            };
+            let lhs = path_segment_certainty(cx, receiver_type_certainty, method, false);
+            let rhs = if type_is_inferrable_from_arguments(cx, expr) {
+                meet(
+                    std::iter::once(receiver_type_certainty).chain(args.iter().map(|arg| expr_type_certainty(cx, arg))),
+                )
+            } else {
+                Certainty::Uncertain
+            };
+            lhs.join(rhs)
+        },
+
+        ExprKind::Tup(exprs) => meet(exprs.iter().map(|expr| expr_type_certainty(cx, expr))),
+
+        ExprKind::Binary(_, lhs, rhs) => expr_type_certainty(cx, lhs).meet(expr_type_certainty(cx, rhs)),
+
+        ExprKind::Lit(_) => Certainty::Certain(None),
+
+        ExprKind::Cast(_, ty) => type_certainty(cx, ty),
+
+        ExprKind::If(_, if_expr, Some(else_expr)) => {
+            expr_type_certainty(cx, if_expr).join(expr_type_certainty(cx, else_expr))
+        },
+
+        ExprKind::Path(qpath) => qpath_certainty(cx, qpath, false),
+
+        ExprKind::Struct(qpath, _, _) => qpath_certainty(cx, qpath, true),
+
+        _ => Certainty::Uncertain,
+    };
+
+    let expr_ty = cx.typeck_results().expr_ty(expr);
+    if let Some(def_id) = adt_def_id(expr_ty) {
+        certainty.with_def_id(def_id)
+    } else {
+        certainty
+    }
+}
+
+struct CertaintyVisitor<'cx, 'tcx> {
+    cx: &'cx LateContext<'tcx>,
+    certainty: Certainty,
+}
+
+impl<'cx, 'tcx> CertaintyVisitor<'cx, 'tcx> {
+    fn new(cx: &'cx LateContext<'tcx>) -> Self {
+        Self {
+            cx,
+            certainty: Certainty::Certain(None),
+        }
+    }
+}
+
+impl<'cx, 'tcx> Visitor<'cx> for CertaintyVisitor<'cx, 'tcx> {
+    fn visit_qpath(&mut self, qpath: &'cx QPath<'_>, hir_id: HirId, _: Span) {
+        self.certainty = self.certainty.meet(qpath_certainty(self.cx, qpath, true));
+        if self.certainty != Certainty::Uncertain {
+            walk_qpath(self, qpath, hir_id);
+        }
+    }
+
+    fn visit_ty(&mut self, ty: &'cx hir::Ty<'_>) {
+        if matches!(ty.kind, TyKind::Infer) {
+            self.certainty = Certainty::Uncertain;
+        }
+        if self.certainty != Certainty::Uncertain {
+            walk_ty(self, ty);
+        }
+    }
+}
+
+fn type_certainty(cx: &LateContext<'_>, ty: &hir::Ty<'_>) -> Certainty {
+    // Handle `TyKind::Path` specially so that its `DefId` can be preserved.
+    //
+    // Note that `CertaintyVisitor::new` initializes the visitor's internal certainty to
+    // `Certainty::Certain(None)`. Furthermore, if a `TyKind::Path` is encountered while traversing
+    // `ty`, the result of the call to `qpath_certainty` is combined with the visitor's internal
+    // certainty using `Certainty::meet`. Thus, if the `TyKind::Path` were not treated specially here,
+    // the resulting certainty would be `Certainty::Certain(None)`.
+    if let TyKind::Path(qpath) = &ty.kind {
+        return qpath_certainty(cx, qpath, true);
+    }
+
+    let mut visitor = CertaintyVisitor::new(cx);
+    visitor.visit_ty(ty);
+    visitor.certainty
+}
+
+fn generic_args_certainty(cx: &LateContext<'_>, args: &GenericArgs<'_>) -> Certainty {
+    let mut visitor = CertaintyVisitor::new(cx);
+    visitor.visit_generic_args(args);
+    visitor.certainty
+}
+
+/// Tries to tell whether a `QPath` resolves to something certain, e.g., whether all of its path
+/// segments generic arguments are are instantiated.
+///
+/// `qpath` could refer to either a type or a value. The heuristic never needs the `DefId` of a
+/// value. So `DefId`s are retained only when `resolves_to_type` is true.
+fn qpath_certainty(cx: &LateContext<'_>, qpath: &QPath<'_>, resolves_to_type: bool) -> Certainty {
+    let certainty = match qpath {
+        QPath::Resolved(ty, path) => {
+            let len = path.segments.len();
+            path.segments.iter().enumerate().fold(
+                ty.map_or(Certainty::Uncertain, |ty| type_certainty(cx, ty)),
+                |parent_certainty, (i, path_segment)| {
+                    path_segment_certainty(cx, parent_certainty, path_segment, i != len - 1 || resolves_to_type)
+                },
+            )
+        },
+
+        QPath::TypeRelative(ty, path_segment) => {
+            path_segment_certainty(cx, type_certainty(cx, ty), path_segment, resolves_to_type)
+        },
+
+        QPath::LangItem(lang_item, _, _) => {
+            cx.tcx
+                .lang_items()
+                .get(*lang_item)
+                .map_or(Certainty::Uncertain, |def_id| {
+                    let generics = cx.tcx.generics_of(def_id);
+                    if generics.parent_count == 0 && generics.params.is_empty() {
+                        Certainty::Certain(if resolves_to_type { Some(def_id) } else { None })
+                    } else {
+                        Certainty::Uncertain
+                    }
+                })
+        },
+    };
+    debug_assert!(resolves_to_type || certainty.to_def_id().is_none());
+    certainty
+}
+
+fn path_segment_certainty(
+    cx: &LateContext<'_>,
+    parent_certainty: Certainty,
+    path_segment: &PathSegment<'_>,
+    resolves_to_type: bool,
+) -> Certainty {
+    let certainty = match update_res(cx, parent_certainty, path_segment).unwrap_or(path_segment.res) {
+        // A definition's type is certain if it refers to something without generics (e.g., a crate or module, or
+        // an unparameterized type), or the generics are instantiated with arguments that are certain.
+        //
+        // If the parent is uncertain, then the current path segment must account for the parent's generic arguments.
+        // Consider the following examples, where the current path segment is `None`:
+        // - `Option::None`             // uncertain; parent (i.e., `Option`) is uncertain
+        // - `Option::<Vec<u64>>::None` // certain; parent (i.e., `Option::<..>`) is certain
+        // - `Option::None::<Vec<u64>>` // certain; parent (i.e., `Option`) is uncertain
+        Res::Def(_, def_id) => {
+            // Checking `res_generics_def_id(..)` before calling `generics_of` avoids an ICE.
+            if cx.tcx.res_generics_def_id(path_segment.res).is_some() {
+                let generics = cx.tcx.generics_of(def_id);
+                let lhs = if (parent_certainty.is_certain() || generics.parent_count == 0) && generics.params.is_empty()
+                {
+                    Certainty::Certain(None)
+                } else {
+                    Certainty::Uncertain
+                };
+                let rhs = path_segment
+                    .args
+                    .map_or(Certainty::Uncertain, |args| generic_args_certainty(cx, args));
+                // See the comment preceding `qpath_certainty`. `def_id` could refer to a type or a value.
+                let certainty = lhs.join_clearing_def_ids(rhs);
+                if resolves_to_type {
+                    certainty.with_def_id(def_id)
+                } else {
+                    certainty
+                }
+            } else {
+                Certainty::Certain(None)
+            }
+        },
+
+        Res::PrimTy(_) | Res::SelfTyParam { .. } | Res::SelfTyAlias { .. } | Res::SelfCtor(_) => {
+            Certainty::Certain(None)
+        },
+
+        // `get_parent` because `hir_id` refers to a `Pat`, and we're interested in the node containing the `Pat`.
+        Res::Local(hir_id) => match cx.tcx.hir().get_parent(hir_id) {
+            // An argument's type is always certain.
+            Node::Param(..) => Certainty::Certain(None),
+            // A local's type is certain if its type annotation is certain or it has an initializer whose
+            // type is certain.
+            Node::Local(local) => {
+                let lhs = local.ty.map_or(Certainty::Uncertain, |ty| type_certainty(cx, ty));
+                let rhs = local
+                    .init
+                    .map_or(Certainty::Uncertain, |init| expr_type_certainty(cx, init));
+                let certainty = lhs.join(rhs);
+                if resolves_to_type {
+                    certainty
+                } else {
+                    certainty.clear_def_id()
+                }
+            },
+            _ => Certainty::Uncertain,
+        },
+
+        _ => Certainty::Uncertain,
+    };
+    debug_assert!(resolves_to_type || certainty.to_def_id().is_none());
+    certainty
+}
+
+/// For at least some `QPath::TypeRelative`, the path segment's `res` can be `Res::Err`.
+/// `update_res` tries to fix the resolution when `parent_certainty` is `Certain(Some(..))`.
+fn update_res(cx: &LateContext<'_>, parent_certainty: Certainty, path_segment: &PathSegment<'_>) -> Option<Res> {
+    if path_segment.res == Res::Err && let Some(def_id) = parent_certainty.to_def_id() {
+        let mut def_path = cx.get_def_path(def_id);
+        def_path.push(path_segment.ident.name);
+        let reses = def_path_res(cx, &def_path.iter().map(Symbol::as_str).collect::<Vec<_>>());
+        if let [res] = reses.as_slice() { Some(*res) } else { None }
+    } else {
+        None
+    }
+}
+
+#[allow(clippy::cast_possible_truncation)]
+fn type_is_inferrable_from_arguments(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
+    let Some(callee_def_id) = (match expr.kind {
+        ExprKind::Call(callee, _) => {
+            let callee_ty = cx.typeck_results().expr_ty(callee);
+            if let ty::FnDef(callee_def_id, _) = callee_ty.kind() {
+                Some(*callee_def_id)
+            } else {
+                None
+            }
+        },
+        ExprKind::MethodCall(_, _, _, _) => cx.typeck_results().type_dependent_def_id(expr.hir_id),
+        _ => None,
+    }) else {
+        return false;
+    };
+
+    let generics = cx.tcx.generics_of(callee_def_id);
+    let fn_sig = cx.tcx.fn_sig(callee_def_id).skip_binder();
+
+    // Check that all type parameters appear in the functions input types.
+    (0..(generics.parent_count + generics.params.len()) as u32).all(|index| {
+        fn_sig
+            .inputs()
+            .iter()
+            .any(|input_ty| contains_param(*input_ty.skip_binder(), index))
+    })
+}
+
+fn self_ty<'tcx>(cx: &LateContext<'tcx>, method_def_id: DefId) -> Ty<'tcx> {
+    cx.tcx.fn_sig(method_def_id).skip_binder().inputs().skip_binder()[0]
+}
+
+fn adt_def_id(ty: Ty<'_>) -> Option<DefId> {
+    ty.peel_refs().ty_adt_def().map(AdtDef::did)
+}
+
+fn contains_param(ty: Ty<'_>, index: u32) -> bool {
+    ty.walk()
+        .any(|arg| matches!(arg.unpack(), GenericArgKind::Type(ty) if ty.is_param(index)))
+}

tests/ui/unwrap_or_else_default.fixed

@@ -74,4 +74,41 @@ fn unwrap_or_else_default() {
     empty_string.unwrap_or_default();
 }
 
+fn type_certainty(option: Option<Vec<u64>>) {
+    option.unwrap_or_default().push(1);
+
+    let option: std::option::Option<std::vec::Vec<u64>> = None;
+    option.unwrap_or_default().push(1);
+
+    let option: Option<Vec<u64>> = None;
+    option.unwrap_or_default().push(1);
+
+    let option = std::option::Option::<std::vec::Vec<u64>>::None;
+    option.unwrap_or_default().push(1);
+
+    let option = Option::<Vec<u64>>::None;
+    option.unwrap_or_default().push(1);
+
+    let option = std::option::Option::None::<std::vec::Vec<u64>>;
+    option.unwrap_or_default().push(1);
+
+    let option = Option::None::<Vec<u64>>;
+    option.unwrap_or_default().push(1);
+
+    let option = None::<Vec<u64>>;
+    option.unwrap_or_default().push(1);
+
+    // should not be changed: type annotation with infer, unconcretized initializer
+    let option: Option<Vec<_>> = None;
+    option.unwrap_or_else(Vec::new).push(1);
+
+    // should not be changed: no type annotation, unconcretized initializer
+    let option = Option::None;
+    option.unwrap_or_else(Vec::new).push(1);
+
+    // should not be changed: no type annotation, unconcretized initializer
+    let option = None;
+    option.unwrap_or_else(Vec::new).push(1);
+}
+
 fn main() {}

tests/ui/unwrap_or_else_default.rs

@@ -74,4 +74,41 @@ fn unwrap_or_else_default() {
     empty_string.unwrap_or_else(|| "".to_string());
 }
 
+fn type_certainty(option: Option<Vec<u64>>) {
+    option.unwrap_or_else(Vec::new).push(1);
+
+    let option: std::option::Option<std::vec::Vec<u64>> = None;
+    option.unwrap_or_else(Vec::new).push(1);
+
+    let option: Option<Vec<u64>> = None;
+    option.unwrap_or_else(Vec::new).push(1);
+
+    let option = std::option::Option::<std::vec::Vec<u64>>::None;
+    option.unwrap_or_else(Vec::new).push(1);
+
+    let option = Option::<Vec<u64>>::None;
+    option.unwrap_or_else(Vec::new).push(1);
+
+    let option = std::option::Option::None::<std::vec::Vec<u64>>;
+    option.unwrap_or_else(Vec::new).push(1);
+
+    let option = Option::None::<Vec<u64>>;
+    option.unwrap_or_else(Vec::new).push(1);
+
+    let option = None::<Vec<u64>>;
+    option.unwrap_or_else(Vec::new).push(1);
+
+    // should not be changed: type annotation with infer, unconcretized initializer
+    let option: Option<Vec<_>> = None;
+    option.unwrap_or_else(Vec::new).push(1);
+
+    // should not be changed: no type annotation, unconcretized initializer
+    let option = Option::None;
+    option.unwrap_or_else(Vec::new).push(1);
+
+    // should not be changed: no type annotation, unconcretized initializer
+    let option = None;
+    option.unwrap_or_else(Vec::new).push(1);
+}
+
 fn main() {}

tests/ui/unwrap_or_else_default.stderr

@@ -36,5 +36,53 @@ error: use of `.unwrap_or_else(..)` to construct default value
 LL |     empty_string.unwrap_or_else(|| "".to_string());
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `empty_string.unwrap_or_default()`
 
-error: aborting due to 6 previous errors
+error: use of `.unwrap_or_else(..)` to construct default value
+  --> $DIR/unwrap_or_else_default.rs:78:5
+   |
+LL |     option.unwrap_or_else(Vec::new).push(1);
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `option.unwrap_or_default()`
+
+error: use of `.unwrap_or_else(..)` to construct default value
+  --> $DIR/unwrap_or_else_default.rs:81:5
+   |
+LL |     option.unwrap_or_else(Vec::new).push(1);
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `option.unwrap_or_default()`
+
+error: use of `.unwrap_or_else(..)` to construct default value
+  --> $DIR/unwrap_or_else_default.rs:84:5
+   |
+LL |     option.unwrap_or_else(Vec::new).push(1);
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `option.unwrap_or_default()`
+
+error: use of `.unwrap_or_else(..)` to construct default value
+  --> $DIR/unwrap_or_else_default.rs:87:5
+   |
+LL |     option.unwrap_or_else(Vec::new).push(1);
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `option.unwrap_or_default()`
+
+error: use of `.unwrap_or_else(..)` to construct default value
+  --> $DIR/unwrap_or_else_default.rs:90:5
+   |
+LL |     option.unwrap_or_else(Vec::new).push(1);
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `option.unwrap_or_default()`
+
+error: use of `.unwrap_or_else(..)` to construct default value
+  --> $DIR/unwrap_or_else_default.rs:93:5
+   |
+LL |     option.unwrap_or_else(Vec::new).push(1);
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `option.unwrap_or_default()`
+
+error: use of `.unwrap_or_else(..)` to construct default value
+  --> $DIR/unwrap_or_else_default.rs:96:5
+   |
+LL |     option.unwrap_or_else(Vec::new).push(1);
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `option.unwrap_or_default()`
+
+error: use of `.unwrap_or_else(..)` to construct default value
+  --> $DIR/unwrap_or_else_default.rs:99:5
+   |
+LL |     option.unwrap_or_else(Vec::new).push(1);
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `option.unwrap_or_default()`
+
+error: aborting due to 14 previous errors