Auto merge of rust-lang#9099 - joshtriplett:unnecessary-lazy-eval-then-some, r=flip1995

Extend unnecessary_lazy_eval to cover `bool::then` -> `bool::then_some`

fixes rust-lang#9097

changelog: Extend `unnecessary_lazy_eval` to convert `bool::then` to `bool::then_some`

Author: bors

clippy_dev/src/update_lints.rs

@@ -553,7 +553,7 @@ fn replace_ident_like(contents: &str, replacements: &[(&str, &str)]) -> Option<S
         pos = m.end();
     }
     result.push_str(&contents[pos..]);
-    edited.then(|| result)
+    edited.then_some(result)
 }
 
 fn round_to_fifty(count: usize) -> usize {

clippy_lints/src/dereference.rs

@@ -744,7 +744,9 @@ fn walk_parents<'tcx>(cx: &LateContext<'tcx>, e: &'tcx Expr<'_>) -> (Position, &
                         },
                     )
                 },
-                ExprKind::Call(func, _) if func.hir_id == child_id => (child_id == e.hir_id).then(|| Position::Callee),
+                ExprKind::Call(func, _) if func.hir_id == child_id => {
+                    (child_id == e.hir_id).then_some(Position::Callee)
+                },
                 ExprKind::Call(func, args) => args
                     .iter()
                     .position(|arg| arg.hir_id == child_id)

clippy_lints/src/entry.rs

@@ -650,7 +650,7 @@ fn find_insert_calls<'tcx>(
     let allow_insert_closure = s.allow_insert_closure;
     let is_single_insert = s.is_single_insert;
     let edits = s.edits;
-    s.can_use_entry.then(|| InsertSearchResults {
+    s.can_use_entry.then_some(InsertSearchResults {
         edits,
         allow_insert_closure,
         is_single_insert,

clippy_lints/src/inherent_impl.rs

@@ -127,7 +127,7 @@ fn get_impl_span(cx: &LateContext<'_>, id: LocalDefId) -> Option<Span> {
         (!span.from_expansion()
             && impl_item.generics.params.is_empty()
             && !is_lint_allowed(cx, MULTIPLE_INHERENT_IMPL, id))
-        .then(|| span)
+        .then_some(span)
     } else {
         None
     }

clippy_lints/src/manual_non_exhaustive.rs

@@ -161,7 +161,7 @@ impl<'tcx> LateLintPass<'tcx> for ManualNonExhaustiveEnum {
                 (matches!(v.data, hir::VariantData::Unit(_))
                     && v.ident.as_str().starts_with('_')
                     && is_doc_hidden(cx.tcx.hir().attrs(v.id)))
-                .then(|| (id, v.span))
+                .then_some((id, v.span))
             });
             if let Some((id, span)) = iter.next()
                 && iter.next().is_none()

clippy_lints/src/matches/manual_map.rs

@@ -105,7 +105,7 @@ fn check<'tcx>(
 
     // Determine which binding mode to use.
     let explicit_ref = some_pat.contains_explicit_ref_binding();
-    let binding_ref = explicit_ref.or_else(|| (ty_ref_count != pat_ref_count).then(|| ty_mutability));
+    let binding_ref = explicit_ref.or_else(|| (ty_ref_count != pat_ref_count).then_some(ty_mutability));
 
     let as_ref_str = match binding_ref {
         Some(Mutability::Mut) => ".as_mut()",

clippy_lints/src/matches/match_same_arms.rs

@@ -38,7 +38,7 @@ pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, arms: &'tcx [Arm<'_>]) {
             normalized_pats[i + 1..]
                 .iter()
                 .enumerate()
-                .find_map(|(j, other)| pat.has_overlapping_values(other).then(|| i + 1 + j))
+                .find_map(|(j, other)| pat.has_overlapping_values(other).then_some(i + 1 + j))
                 .unwrap_or(normalized_pats.len())
         })
         .collect();
@@ -55,7 +55,7 @@ pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, arms: &'tcx [Arm<'_>]) {
                 .zip(forwards_blocking_idxs[..i].iter().copied().rev())
                 .skip_while(|&(_, forward_block)| forward_block > i)
                 .find_map(|((j, other), forward_block)| {
-                    (forward_block == i || pat.has_overlapping_values(other)).then(|| j)
+                    (forward_block == i || pat.has_overlapping_values(other)).then_some(j)
                 })
                 .unwrap_or(0)
         })

clippy_lints/src/matches/mod.rs

@@ -1061,7 +1061,7 @@ fn contains_cfg_arm(cx: &LateContext<'_>, e: &Expr<'_>, scrutinee: &Expr<'_>, ar
     let start = scrutinee_span.hi();
     let mut arm_spans = arms.iter().map(|arm| {
         let data = arm.span.data();
-        (data.ctxt == SyntaxContext::root()).then(|| (data.lo, data.hi))
+        (data.ctxt == SyntaxContext::root()).then_some((data.lo, data.hi))
     });
     let end = e.span.hi();
 
@@ -1095,7 +1095,7 @@ fn contains_cfg_arm(cx: &LateContext<'_>, e: &Expr<'_>, scrutinee: &Expr<'_>, ar
             parent: None,
         }
         .span();
-        (!span_contains_cfg(cx, span)).then(|| next_start).ok_or(())
+        (!span_contains_cfg(cx, span)).then_some(next_start).ok_or(())
     });
     match found {
         Ok(start) => {

clippy_lints/src/methods/manual_str_repeat.rs

@@ -43,7 +43,7 @@ fn parse_repeat_arg(cx: &LateContext<'_>, e: &Expr<'_>) -> Option<RepeatKind> {
             Some(RepeatKind::String)
         } else {
             let ty = ty.peel_refs();
-            (ty.is_str() || is_type_diagnostic_item(cx, ty, sym::String)).then(|| RepeatKind::String)
+            (ty.is_str() || is_type_diagnostic_item(cx, ty, sym::String)).then_some(RepeatKind::String)
         }
     }
 }

clippy_lints/src/methods/mod.rs

@@ -2737,6 +2737,12 @@ impl Methods {
                     }
                 },
                 ("take", []) => needless_option_take::check(cx, expr, recv),
+                ("then", [arg]) => {
+                    if !meets_msrv(self.msrv, msrvs::BOOL_THEN_SOME) {
+                        return;
+                    }
+                    unnecessary_lazy_eval::check(cx, expr, recv, arg, "then_some");
+                },
                 ("to_os_string" | "to_owned" | "to_path_buf" | "to_vec", []) => {
                     implicit_clone::check(cx, name, expr, recv);
                 },

clippy_lints/src/methods/unnecessary_lazy_eval.rs

@@ -20,8 +20,9 @@ pub(super) fn check<'tcx>(
 ) {
     let is_option = is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(recv), sym::Option);
     let is_result = is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(recv), sym::Result);
+    let is_bool = cx.typeck_results().expr_ty(recv).is_bool();
 
-    if is_option || is_result {
+    if is_option || is_result || is_bool {
         if let hir::ExprKind::Closure { body, .. } = arg.kind {
             let body = cx.tcx.hir().body(body);
             let body_expr = &body.value;
@@ -33,8 +34,10 @@ pub(super) fn check<'tcx>(
             if eager_or_lazy::switch_to_eager_eval(cx, body_expr) {
                 let msg = if is_option {
                     "unnecessary closure used to substitute value for `Option::None`"
-                } else {
+                } else if is_result {
                     "unnecessary closure used to substitute value for `Result::Err`"
+                } else {
+                    "unnecessary closure used with `bool::then`"
                 };
                 let applicability = if body
                     .params

clippy_lints/src/option_if_let_else.rs

@@ -146,7 +146,7 @@ fn detect_option_if_let_else<'tcx>(cx: &LateContext<'tcx>, expr: &Expr<'tcx>) ->
                 });
                 if let ExprKind::Path(QPath::Resolved(None, Path { res: Res::Local(local_id), .. })) = e.kind {
                     match some_captures.get(local_id)
-                        .or_else(|| (method_sugg == "map_or_else").then(|| ()).and_then(|_| none_captures.get(local_id)))
+                        .or_else(|| (method_sugg == "map_or_else").then_some(()).and_then(|_| none_captures.get(local_id)))
                     {
                         Some(CaptureKind::Value | CaptureKind::Ref(Mutability::Mut)) => return None,
                         Some(CaptureKind::Ref(Mutability::Not)) if as_mut => return None,

clippy_lints/src/ptr.rs

@@ -501,7 +501,7 @@ fn check_mut_from_ref<'tcx>(cx: &LateContext<'tcx>, sig: &FnSig<'_>, body: Optio
             .iter()
             .filter_map(get_rptr_lm)
             .filter(|&(lt, _, _)| lt.name == out.name)
-            .map(|(_, mutability, span)| (mutability == Mutability::Not).then(|| span))
+            .map(|(_, mutability, span)| (mutability == Mutability::Not).then_some(span))
             .collect();
         if let Some(args) = args
             && !args.is_empty()

clippy_lints/src/swap_ptr_to_ref.rs

@@ -73,7 +73,7 @@ fn is_ptr_to_ref(cx: &LateContext<'_>, e: &Expr<'_>, ctxt: SyntaxContext) -> (bo
         && let ExprKind::Unary(UnOp::Deref, derefed_expr) = borrowed_expr.kind
         && cx.typeck_results().expr_ty(derefed_expr).is_unsafe_ptr()
     {
-        (true, (borrowed_expr.span.ctxt() == ctxt || derefed_expr.span.ctxt() == ctxt).then(|| derefed_expr.span))
+        (true, (borrowed_expr.span.ctxt() == ctxt || derefed_expr.span.ctxt() == ctxt).then_some(derefed_expr.span))
     } else {
         (false, None)
     }

clippy_lints/src/utils/internal_lints/metadata_collector.rs

@@ -843,7 +843,7 @@ fn get_lint_group(cx: &LateContext<'_>, lint_id: LintId) -> Option<String> {
 fn get_lint_level_from_group(lint_group: &str) -> Option<&'static str> {
     DEFAULT_LINT_LEVELS
         .iter()
-        .find_map(|(group_name, group_level)| (*group_name == lint_group).then(|| *group_level))
+        .find_map(|(group_name, group_level)| (*group_name == lint_group).then_some(*group_level))
 }
 
 pub(super) fn is_deprecated_lint(cx: &LateContext<'_>, ty: &hir::Ty<'_>) -> bool {

clippy_lints/src/write.rs

@@ -515,7 +515,7 @@ impl Write {
             args.push(arg, span);
         }
 
-        parser.errors.is_empty().then(move || args)
+        parser.errors.is_empty().then_some(args)
     }
 
     /// Checks the arguments of `print[ln]!` and `write[ln]!` calls. It will return a tuple of two

clippy_utils/src/lib.rs

@@ -1016,7 +1016,7 @@ pub fn can_move_expr_to_closure<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'
         captures: HirIdMap::default(),
     };
     v.visit_expr(expr);
-    v.allow_closure.then(|| v.captures)
+    v.allow_closure.then_some(v.captures)
 }
 
 /// Returns the method names and argument list of nested method call expressions that make up

clippy_utils/src/msrvs.rs

@@ -12,6 +12,7 @@ macro_rules! msrv_aliases {
 
 // names may refer to stabilized feature flags or library items
 msrv_aliases! {
+    1,62,0 { BOOL_THEN_SOME }
     1,53,0 { OR_PATTERNS, MANUAL_BITS, BTREE_MAP_RETAIN, BTREE_SET_RETAIN }
     1,52,0 { STR_SPLIT_ONCE, REM_EUCLID_CONST }
     1,51,0 { BORROW_AS_PTR, UNSIGNED_ABS }

clippy_utils/src/source.rs

@@ -353,7 +353,7 @@ pub fn snippet_with_context<'a>(
 /// span containing `m!(0)`.
 pub fn walk_span_to_context(span: Span, outer: SyntaxContext) -> Option<Span> {
     let outer_span = hygiene::walk_chain(span, outer);
-    (outer_span.ctxt() == outer).then(|| outer_span)
+    (outer_span.ctxt() == outer).then_some(outer_span)
 }
 
 /// Removes block comments from the given `Vec` of lines.

tests/ui/unnecessary_lazy_eval.fixed

@@ -30,6 +30,7 @@ fn main() {
     let ext_opt = Some(42);
     let nested_opt = Some(Some(42));
     let nested_tuple_opt = Some(Some((42, 43)));
+    let cond = true;
 
     // Should lint - Option
     let _ = opt.unwrap_or(2);
@@ -42,6 +43,7 @@ fn main() {
     let _ = opt.get_or_insert(2);
     let _ = opt.ok_or(2);
     let _ = nested_tuple_opt.unwrap_or(Some((1, 2)));
+    let _ = cond.then_some(astronomers_pi);
 
     // Cases when unwrap is not called on a simple variable
     let _ = Some(10).unwrap_or(2);

tests/ui/unnecessary_lazy_eval.rs

@@ -30,6 +30,7 @@ fn main() {
     let ext_opt = Some(42);
     let nested_opt = Some(Some(42));
     let nested_tuple_opt = Some(Some((42, 43)));
+    let cond = true;
 
     // Should lint - Option
     let _ = opt.unwrap_or_else(|| 2);
@@ -42,6 +43,7 @@ fn main() {
     let _ = opt.get_or_insert_with(|| 2);
     let _ = opt.ok_or_else(|| 2);
     let _ = nested_tuple_opt.unwrap_or_else(|| Some((1, 2)));
+    let _ = cond.then(|| astronomers_pi);
 
     // Cases when unwrap is not called on a simple variable
     let _ = Some(10).unwrap_or_else(|| 2);