diff --git a/src/libcore/bool.rs b/src/libcore/bool.rs
index aa1ba7affc1..1b3c254a05f 100644
--- a/src/libcore/bool.rs
+++ b/src/libcore/bool.rs
@@ -9,12 +9,12 @@ impl bool {
     /// ```
     /// #![feature(bool_to_option)]
     ///
-    /// assert_eq!(false.to_option(0), None);
-    /// assert_eq!(true.to_option(0), Some(0));
+    /// assert_eq!(false.then_some(0), None);
+    /// assert_eq!(true.then_some(0), Some(0));
     /// ```
     #[unstable(feature = "bool_to_option", issue = "64260")]
     #[inline]
-    pub fn to_option<T>(self, t: T) -> Option<T> {
+    pub fn then_some<T>(self, t: T) -> Option<T> {
         if self {
             Some(t)
         } else {
@@ -29,12 +29,12 @@ impl bool {
     /// ```
     /// #![feature(bool_to_option)]
     ///
-    /// assert_eq!(false.to_option_with(|| 0), None);
-    /// assert_eq!(true.to_option_with(|| 0), Some(0));
+    /// assert_eq!(false.then(|| 0), None);
+    /// assert_eq!(true.then(|| 0), Some(0));
     /// ```
     #[unstable(feature = "bool_to_option", issue = "64260")]
     #[inline]
-    pub fn to_option_with<T, F: FnOnce() -> T>(self, f: F) -> Option<T> {
+    pub fn then<T, F: FnOnce() -> T>(self, f: F) -> Option<T> {
         if self {
             Some(f())
         } else {
diff --git a/src/libcore/tests/bool.rs b/src/libcore/tests/bool.rs
index 8ec151b63ff..e89eb2c7f94 100644
--- a/src/libcore/tests/bool.rs
+++ b/src/libcore/tests/bool.rs
@@ -1,7 +1,7 @@
 #[test]
 fn test_bool_to_option() {
-    assert_eq!(false.to_option(0), None);
-    assert_eq!(true.to_option(0), Some(0));
-    assert_eq!(false.to_option_with(|| 0), None);
-    assert_eq!(true.to_option_with(|| 0), Some(0));
+    assert_eq!(false.then_some(0), None);
+    assert_eq!(true.then_some(0), Some(0));
+    assert_eq!(false.then(|| 0), None);
+    assert_eq!(true.then(|| 0), Some(0));
 }
diff --git a/src/libfmt_macros/lib.rs b/src/libfmt_macros/lib.rs
index 2e8837bb63f..2ecbe770729 100644
--- a/src/libfmt_macros/lib.rs
+++ b/src/libfmt_macros/lib.rs
@@ -645,7 +645,7 @@ impl<'a> Parser<'a> {
                 break;
             }
         }
-        found.to_option(cur)
+        found.then_some(cur)
     }
 }
 
diff --git a/src/librustc/hir/map/blocks.rs b/src/librustc/hir/map/blocks.rs
index 5c5ce8c668d..8f9f3983262 100644
--- a/src/librustc/hir/map/blocks.rs
+++ b/src/librustc/hir/map/blocks.rs
@@ -147,7 +147,7 @@ impl<'a> FnLikeNode<'a> {
             map::Node::Expr(e) => e.is_fn_like(),
             _ => false
         };
-        fn_like.to_option(FnLikeNode { node })
+        fn_like.then_some(FnLikeNode { node })
     }
 
     pub fn body(self) -> ast::BodyId {
diff --git a/src/librustc/infer/outlives/verify.rs b/src/librustc/infer/outlives/verify.rs
index aebf93d85c5..3e28145c0fa 100644
--- a/src/librustc/infer/outlives/verify.rs
+++ b/src/librustc/infer/outlives/verify.rs
@@ -211,7 +211,7 @@ impl<'cx, 'tcx> VerifyBoundCx<'cx, 'tcx> {
                 (r, p)
             );
             let p_ty = p.to_ty(tcx);
-            compare_ty(p_ty).to_option(ty::OutlivesPredicate(p_ty, r))
+            compare_ty(p_ty).then_some(ty::OutlivesPredicate(p_ty, r))
         });
 
         param_bounds
diff --git a/src/librustc/traits/error_reporting.rs b/src/librustc/traits/error_reporting.rs
index 6f27adf194a..412300f0b10 100644
--- a/src/librustc/traits/error_reporting.rs
+++ b/src/librustc/traits/error_reporting.rs
@@ -363,7 +363,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
             return None
         };
 
-        tcx.has_attr(impl_def_id, sym::rustc_on_unimplemented).to_option(impl_def_id)
+        tcx.has_attr(impl_def_id, sym::rustc_on_unimplemented).then_some(impl_def_id)
     }
 
     fn describe_generator(&self, body_id: hir::BodyId) -> Option<&'static str> {
diff --git a/src/librustc/ty/mod.rs b/src/librustc/ty/mod.rs
index ca1758ee78a..05a2704cc5d 100644
--- a/src/librustc/ty/mod.rs
+++ b/src/librustc/ty/mod.rs
@@ -2784,7 +2784,7 @@ impl<'tcx> TyCtxt<'tcx> {
             }
         };
 
-        is_associated_item.to_option_with(|| self.associated_item(def_id))
+        is_associated_item.then(|| self.associated_item(def_id))
     }
 
     fn associated_item_from_trait_item_ref(self,
@@ -3249,7 +3249,7 @@ fn param_env(tcx: TyCtxt<'_>, def_id: DefId) -> ParamEnv<'_> {
     let unnormalized_env = ty::ParamEnv::new(
         tcx.intern_predicates(&predicates),
         traits::Reveal::UserFacing,
-        tcx.sess.opts.debugging_opts.chalk.to_option(def_id),
+        tcx.sess.opts.debugging_opts.chalk.then_some(def_id),
     );
 
     let body_id = tcx.hir().as_local_hir_id(def_id).map_or(hir::DUMMY_HIR_ID, |id| {
diff --git a/src/librustc/ty/query/job.rs b/src/librustc/ty/query/job.rs
index 843222cfcac..2f30b797fb1 100644
--- a/src/librustc/ty/query/job.rs
+++ b/src/librustc/ty/query/job.rs
@@ -303,7 +303,7 @@ fn connected_to_root<'tcx>(
         return true;
     }
 
-    visit_waiters(query, |_, successor| connected_to_root(successor, visited).to_option(None))
+    visit_waiters(query, |_, successor| connected_to_root(successor, visited).then_some(None))
         .is_some()
 }
 
diff --git a/src/librustc_codegen_llvm/common.rs b/src/librustc_codegen_llvm/common.rs
index 369a098a5c6..419e99d55d7 100644
--- a/src/librustc_codegen_llvm/common.rs
+++ b/src/librustc_codegen_llvm/common.rs
@@ -245,7 +245,7 @@ impl ConstMethods<'tcx> for CodegenCx<'ll, 'tcx> {
             let (mut lo, mut hi) = (0u64, 0u64);
             let success = llvm::LLVMRustConstInt128Get(v, sign_ext,
                                                         &mut hi, &mut lo);
-            success.to_option(hi_lo_to_u128(lo, hi))
+            success.then_some(hi_lo_to_u128(lo, hi))
         })
     }
 
diff --git a/src/librustc_codegen_ssa/back/rpath.rs b/src/librustc_codegen_ssa/back/rpath.rs
index c61f16da264..cd3d99951e2 100644
--- a/src/librustc_codegen_ssa/back/rpath.rs
+++ b/src/librustc_codegen_ssa/back/rpath.rs
@@ -119,7 +119,7 @@ fn path_relative_from(path: &Path, base: &Path) -> Option<PathBuf> {
     use std::path::Component;
 
     if path.is_absolute() != base.is_absolute() {
-        path.is_absolute().to_option_with(|| PathBuf::from(path))
+        path.is_absolute().then(|| PathBuf::from(path))
     } else {
         let mut ita = path.components();
         let mut itb = base.components();
diff --git a/src/librustc_codegen_ssa/back/symbol_export.rs b/src/librustc_codegen_ssa/back/symbol_export.rs
index 00519814071..cea5dc18c13 100644
--- a/src/librustc_codegen_ssa/back/symbol_export.rs
+++ b/src/librustc_codegen_ssa/back/symbol_export.rs
@@ -85,7 +85,7 @@ fn reachable_non_generics_provider(
             match tcx.hir().get(hir_id) {
                 Node::ForeignItem(..) => {
                     let def_id = tcx.hir().local_def_id(hir_id);
-                    tcx.is_statically_included_foreign_item(def_id).to_option(def_id)
+                    tcx.is_statically_included_foreign_item(def_id).then_some(def_id)
                 }
 
                 // Only consider nodes that actually have exported symbols.
diff --git a/src/librustc_codegen_ssa/lib.rs b/src/librustc_codegen_ssa/lib.rs
index 2c2150e01a3..9919666027a 100644
--- a/src/librustc_codegen_ssa/lib.rs
+++ b/src/librustc_codegen_ssa/lib.rs
@@ -70,10 +70,10 @@ impl<M> ModuleCodegen<M> {
                             emit_bc_compressed: bool,
                             outputs: &OutputFilenames) -> CompiledModule {
         let object = emit_obj
-            .to_option_with(|| outputs.temp_path(OutputType::Object, Some(&self.name)));
+            .then(|| outputs.temp_path(OutputType::Object, Some(&self.name)));
         let bytecode = emit_bc
-            .to_option_with(|| outputs.temp_path(OutputType::Bitcode, Some(&self.name)));
-        let bytecode_compressed = emit_bc_compressed.to_option_with(|| {
+            .then(|| outputs.temp_path(OutputType::Bitcode, Some(&self.name)));
+        let bytecode_compressed = emit_bc_compressed.then(|| {
             outputs.temp_path(OutputType::Bitcode, Some(&self.name))
                 .with_extension(RLIB_BYTECODE_EXTENSION)
         });
diff --git a/src/librustc_interface/passes.rs b/src/librustc_interface/passes.rs
index 753d7b02cca..2a4bc41f850 100644
--- a/src/librustc_interface/passes.rs
+++ b/src/librustc_interface/passes.rs
@@ -547,7 +547,7 @@ fn output_contains_path(output_paths: &[PathBuf], input_path: &PathBuf) -> bool
 }
 
 fn output_conflicts_with_dir(output_paths: &[PathBuf]) -> Option<PathBuf> {
-    let check = |output_path: &PathBuf| output_path.is_dir().to_option_with(|| output_path.clone());
+    let check = |output_path: &PathBuf| output_path.is_dir().then(|| output_path.clone());
     check_output(output_paths, check)
 }
 
diff --git a/src/librustc_interface/queries.rs b/src/librustc_interface/queries.rs
index 7413899fac6..061d3854a9a 100644
--- a/src/librustc_interface/queries.rs
+++ b/src/librustc_interface/queries.rs
@@ -117,7 +117,7 @@ impl<'tcx> Queries<'tcx> {
 
     pub fn dep_graph_future(&self) -> Result<&Query<Option<DepGraphFuture>>> {
         self.dep_graph_future.compute(|| {
-            Ok(self.session().opts.build_dep_graph().to_option_with(|| {
+            Ok(self.session().opts.build_dep_graph().then(|| {
                 rustc_incremental::load_dep_graph(self.session())
             }))
         })
diff --git a/src/librustc_interface/util.rs b/src/librustc_interface/util.rs
index 3d227f91ed6..8c225b83f40 100644
--- a/src/librustc_interface/util.rs
+++ b/src/librustc_interface/util.rs
@@ -107,7 +107,7 @@ const STACK_SIZE: usize = 16 * 1024 * 1024;
 fn get_stack_size() -> Option<usize> {
     // FIXME: Hacks on hacks. If the env is trying to override the stack size
     // then *don't* set it explicitly.
-    env::var_os("RUST_MIN_STACK").is_none().to_option(STACK_SIZE)
+    env::var_os("RUST_MIN_STACK").is_none().then_some(STACK_SIZE)
 }
 
 struct Sink(Arc<Mutex<Vec<u8>>>);
@@ -281,7 +281,7 @@ fn get_rustc_path_inner(bin_path: &str) -> Option<PathBuf> {
             } else {
                 "rustc"
             });
-            candidate.exists().to_option(candidate)
+            candidate.exists().then_some(candidate)
         })
         .next()
 }
diff --git a/src/librustc_lint/builtin.rs b/src/librustc_lint/builtin.rs
index 080448911af..10b00d35d9b 100644
--- a/src/librustc_lint/builtin.rs
+++ b/src/librustc_lint/builtin.rs
@@ -1491,7 +1491,7 @@ impl ExplicitOutlivesRequirements {
             match pred {
                 ty::Predicate::TypeOutlives(outlives) => {
                     let outlives = outlives.skip_binder();
-                    outlives.0.is_param(index).to_option(outlives.1)
+                    outlives.0.is_param(index).then_some(outlives.1)
                 }
                 _ => None
             }
@@ -1550,7 +1550,7 @@ impl ExplicitOutlivesRequirements {
                             }),
                         _ => false,
                     };
-                    is_inferred.to_option((i, bound.span()))
+                    is_inferred.then_some((i, bound.span()))
                 } else {
                     None
                 }
diff --git a/src/librustc_metadata/creader.rs b/src/librustc_metadata/creader.rs
index 20fd9445f0e..25bd2c45da5 100644
--- a/src/librustc_metadata/creader.rs
+++ b/src/librustc_metadata/creader.rs
@@ -803,7 +803,7 @@ impl<'a> CrateLoader<'a> {
         // and see what's a global allocator, including if we ourselves are a
         // global allocator.
         let mut global_allocator = self.cstore.has_global_allocator
-            .to_option_with(|| Symbol::intern("this crate"));
+            .then(|| Symbol::intern("this crate"));
         self.cstore.iter_crate_data(|_, data| {
             if !data.has_global_allocator() {
                 return
diff --git a/src/librustc_mir/borrow_check/nll/mod.rs b/src/librustc_mir/borrow_check/nll/mod.rs
index 66ec84e8316..7a5bbb4d892 100644
--- a/src/librustc_mir/borrow_check/nll/mod.rs
+++ b/src/librustc_mir/borrow_check/nll/mod.rs
@@ -173,7 +173,7 @@ pub(in crate::borrow_check) fn compute_regions<'cx, 'tcx>(
     Option<Rc<Output<RegionVid, BorrowIndex, LocationIndex, Local, MovePathIndex>>>,
     Option<ClosureRegionRequirements<'tcx>>,
 ) {
-    let mut all_facts = AllFacts::enabled(infcx.tcx).to_option(AllFacts::default());
+    let mut all_facts = AllFacts::enabled(infcx.tcx).then_some(AllFacts::default());
 
     let universal_regions = Rc::new(universal_regions);
 
diff --git a/src/librustc_mir/borrow_check/nll/region_infer/mod.rs b/src/librustc_mir/borrow_check/nll/region_infer/mod.rs
index 2f99494308a..0b3cb29e39e 100644
--- a/src/librustc_mir/borrow_check/nll/region_infer/mod.rs
+++ b/src/librustc_mir/borrow_check/nll/region_infer/mod.rs
@@ -493,7 +493,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         // functions below, which will trigger them to report errors
         // eagerly.
         let mut outlives_requirements =
-            infcx.tcx.is_closure(mir_def_id).to_option_with(|| vec![]);
+            infcx.tcx.is_closure(mir_def_id).then(|| vec![]);
 
         self.check_type_tests(
             infcx,
diff --git a/src/librustc_mir/hair/pattern/mod.rs b/src/librustc_mir/hair/pattern/mod.rs
index 68cd16490d6..0086c3b0e10 100644
--- a/src/librustc_mir/hair/pattern/mod.rs
+++ b/src/librustc_mir/hair/pattern/mod.rs
@@ -1154,7 +1154,7 @@ pub fn compare_const_vals<'tcx>(
 ) -> Option<Ordering> {
     trace!("compare_const_vals: {:?}, {:?}", a, b);
 
-    let from_bool = |v: bool| v.to_option(Ordering::Equal);
+    let from_bool = |v: bool| v.then_some(Ordering::Equal);
 
     let fallback = || from_bool(a == b);
 
diff --git a/src/librustc_mir/interpret/memory.rs b/src/librustc_mir/interpret/memory.rs
index 9cb5a8295e0..8f177ad1225 100644
--- a/src/librustc_mir/interpret/memory.rs
+++ b/src/librustc_mir/interpret/memory.rs
@@ -324,7 +324,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> {
         size: Size,
         align: Align,
     ) -> InterpResult<'tcx, Option<Pointer<M::PointerTag>>> {
-        let align = M::CHECK_ALIGN.to_option(align);
+        let align = M::CHECK_ALIGN.then_some(align);
         self.check_ptr_access_align(sptr, size, align, CheckInAllocMsg::MemoryAccessTest)
     }
 
diff --git a/src/librustc_mir/interpret/step.rs b/src/librustc_mir/interpret/step.rs
index d285808a975..55b9427a75b 100644
--- a/src/librustc_mir/interpret/step.rs
+++ b/src/librustc_mir/interpret/step.rs
@@ -157,9 +157,9 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
             }
 
             BinaryOp(bin_op, ref left, ref right) => {
-                let layout = binop_left_homogeneous(bin_op).to_option(dest.layout);
+                let layout = binop_left_homogeneous(bin_op).then_some(dest.layout);
                 let left = self.read_immediate(self.eval_operand(left, layout)?)?;
-                let layout = binop_right_homogeneous(bin_op).to_option(left.layout);
+                let layout = binop_right_homogeneous(bin_op).then_some(left.layout);
                 let right = self.read_immediate(self.eval_operand(right, layout)?)?;
                 self.binop_ignore_overflow(
                     bin_op,
@@ -172,7 +172,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
             CheckedBinaryOp(bin_op, ref left, ref right) => {
                 // Due to the extra boolean in the result, we can never reuse the `dest.layout`.
                 let left = self.read_immediate(self.eval_operand(left, None)?)?;
-                let layout = binop_right_homogeneous(bin_op).to_option(left.layout);
+                let layout = binop_right_homogeneous(bin_op).then_some(left.layout);
                 let right = self.read_immediate(self.eval_operand(right, layout)?)?;
                 self.binop_with_overflow(
                     bin_op,
diff --git a/src/librustc_mir/monomorphize/partitioning.rs b/src/librustc_mir/monomorphize/partitioning.rs
index 6f2e501fc0e..591f220549d 100644
--- a/src/librustc_mir/monomorphize/partitioning.rs
+++ b/src/librustc_mir/monomorphize/partitioning.rs
@@ -761,7 +761,7 @@ fn compute_codegen_unit_name(
             .iter()
             .map(|part| part.data.as_symbol());
 
-        let volatile_suffix = volatile.to_option("volatile");
+        let volatile_suffix = volatile.then_some("volatile");
 
         name_builder.build_cgu_name(def_path.krate, components, volatile_suffix)
     }).clone()
diff --git a/src/librustc_mir/transform/check_unsafety.rs b/src/librustc_mir/transform/check_unsafety.rs
index c4d6ada05dc..284285c327c 100644
--- a/src/librustc_mir/transform/check_unsafety.rs
+++ b/src/librustc_mir/transform/check_unsafety.rs
@@ -658,7 +658,7 @@ pub fn check_unsafety(tcx: TyCtxt<'_>, def_id: DefId) {
     let mut unsafe_blocks: Vec<_> = unsafe_blocks.into_iter().collect();
     unsafe_blocks.sort_by_cached_key(|(hir_id, _)| tcx.hir().hir_to_node_id(*hir_id));
     let used_unsafe: FxHashSet<_> = unsafe_blocks.iter()
-        .flat_map(|&&(id, used)| used.to_option(id))
+        .flat_map(|&&(id, used)| used.then_some(id))
         .collect();
     for &(block_id, is_used) in unsafe_blocks {
         if !is_used {
diff --git a/src/librustc_parse/config.rs b/src/librustc_parse/config.rs
index bba901a18ef..7dbfd98de75 100644
--- a/src/librustc_parse/config.rs
+++ b/src/librustc_parse/config.rs
@@ -75,7 +75,7 @@ macro_rules! configure {
 impl<'a> StripUnconfigured<'a> {
     pub fn configure<T: HasAttrs>(&mut self, mut node: T) -> Option<T> {
         self.process_cfg_attrs(&mut node);
-        self.in_cfg(node.attrs()).to_option(node)
+        self.in_cfg(node.attrs()).then_some(node)
     }
 
     /// Parse and expand all `cfg_attr` attributes into a list of attributes
diff --git a/src/librustc_resolve/diagnostics.rs b/src/librustc_resolve/diagnostics.rs
index afc43bbb0da..8dd45f5df4c 100644
--- a/src/librustc_resolve/diagnostics.rs
+++ b/src/librustc_resolve/diagnostics.rs
@@ -422,7 +422,7 @@ impl<'a> Resolver<'a> {
                 Scope::MacroUsePrelude => {
                     suggestions.extend(this.macro_use_prelude.iter().filter_map(|(name, binding)| {
                         let res = binding.res();
-                        filter_fn(res).to_option(TypoSuggestion::from_res(*name, res))
+                        filter_fn(res).then_some(TypoSuggestion::from_res(*name, res))
                     }));
                 }
                 Scope::BuiltinAttrs => {
@@ -436,7 +436,7 @@ impl<'a> Resolver<'a> {
                 Scope::ExternPrelude => {
                     suggestions.extend(this.extern_prelude.iter().filter_map(|(ident, _)| {
                         let res = Res::Def(DefKind::Mod, DefId::local(CRATE_DEF_INDEX));
-                        filter_fn(res).to_option(TypoSuggestion::from_res(ident.name, res))
+                        filter_fn(res).then_some(TypoSuggestion::from_res(ident.name, res))
                     }));
                 }
                 Scope::ToolPrelude => {
@@ -459,7 +459,7 @@ impl<'a> Resolver<'a> {
                     suggestions.extend(
                         primitive_types.iter().flat_map(|(name, prim_ty)| {
                             let res = Res::PrimTy(*prim_ty);
-                            filter_fn(res).to_option(TypoSuggestion::from_res(*name, res))
+                            filter_fn(res).then_some(TypoSuggestion::from_res(*name, res))
                         })
                     )
                 }
diff --git a/src/librustc_resolve/late.rs b/src/librustc_resolve/late.rs
index bd68e3b8816..4f95d6fe70f 100644
--- a/src/librustc_resolve/late.rs
+++ b/src/librustc_resolve/late.rs
@@ -496,7 +496,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LateResolutionVisitor<'a, '_> {
                 GenericParamKind::Lifetime { .. } => None,
                 GenericParamKind::Type { ref default, .. } => {
                     found_default |= default.is_some();
-                    found_default.to_option((Ident::with_dummy_span(param.ident.name), Res::Err))
+                    found_default.then_some((Ident::with_dummy_span(param.ident.name), Res::Err))
                 }
             }));
 
diff --git a/src/librustc_target/abi/call/aarch64.rs b/src/librustc_target/abi/call/aarch64.rs
index 524aea05773..06c001e577b 100644
--- a/src/librustc_target/abi/call/aarch64.rs
+++ b/src/librustc_target/abi/call/aarch64.rs
@@ -20,7 +20,7 @@ fn is_homogeneous_aggregate<'a, Ty, C>(cx: &C, arg: &mut ArgAbi<'a, Ty>)
             RegKind::Vector => size.bits() == 64 || size.bits() == 128
         };
 
-        valid_unit.to_option(Uniform { unit, total: size })
+        valid_unit.then_some(Uniform { unit, total: size })
     })
 }
 
diff --git a/src/librustc_target/abi/call/arm.rs b/src/librustc_target/abi/call/arm.rs
index e18fe2973c8..36971c1c501 100644
--- a/src/librustc_target/abi/call/arm.rs
+++ b/src/librustc_target/abi/call/arm.rs
@@ -21,7 +21,7 @@ fn is_homogeneous_aggregate<'a, Ty, C>(cx: &C, arg: &mut ArgAbi<'a, Ty>)
             RegKind::Vector => size.bits() == 64 || size.bits() == 128
         };
 
-        valid_unit.to_option(Uniform { unit, total: size })
+        valid_unit.then_some(Uniform { unit, total: size })
     })
 }
 
diff --git a/src/librustc_target/abi/call/mod.rs b/src/librustc_target/abi/call/mod.rs
index 16c53fb5503..5119464b1cc 100644
--- a/src/librustc_target/abi/call/mod.rs
+++ b/src/librustc_target/abi/call/mod.rs
@@ -416,7 +416,7 @@ impl<'a, Ty> ArgAbi<'a, Ty> {
         // i686-pc-windows-msvc, it results in wrong stack offsets.
         // attrs.pointee_align = Some(self.layout.align.abi);
 
-        let extra_attrs = self.layout.is_unsized().to_option(ArgAttributes::new());
+        let extra_attrs = self.layout.is_unsized().then_some(ArgAttributes::new());
 
         self.mode = PassMode::Indirect(attrs, extra_attrs);
     }
diff --git a/src/librustc_target/abi/call/powerpc64.rs b/src/librustc_target/abi/call/powerpc64.rs
index 82c9dc323ce..fe4594802f6 100644
--- a/src/librustc_target/abi/call/powerpc64.rs
+++ b/src/librustc_target/abi/call/powerpc64.rs
@@ -32,7 +32,7 @@ fn is_homogeneous_aggregate<'a, Ty, C>(cx: &C, arg: &mut ArgAbi<'a, Ty>, abi: AB
             RegKind::Vector => arg.layout.size.bits() == 128
         };
 
-        valid_unit.to_option(Uniform { unit, total: arg.layout.size })
+        valid_unit.then_some(Uniform { unit, total: arg.layout.size })
     })
 }
 
diff --git a/src/librustc_target/abi/call/sparc64.rs b/src/librustc_target/abi/call/sparc64.rs
index 97f035be8e5..32be7b89cb0 100644
--- a/src/librustc_target/abi/call/sparc64.rs
+++ b/src/librustc_target/abi/call/sparc64.rs
@@ -20,7 +20,7 @@ fn is_homogeneous_aggregate<'a, Ty, C>(cx: &C, arg: &mut ArgAbi<'a, Ty>)
             RegKind::Vector => arg.layout.size.bits() == 128
         };
 
-        valid_unit.to_option(Uniform { unit, total: arg.layout.size })
+        valid_unit.then_some(Uniform { unit, total: arg.layout.size })
     })
 }
 
diff --git a/src/librustc_typeck/check/method/probe.rs b/src/librustc_typeck/check/method/probe.rs
index cb23a3f1499..992308183b4 100644
--- a/src/librustc_typeck/check/method/probe.rs
+++ b/src/librustc_typeck/check/method/probe.rs
@@ -1105,7 +1105,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
             r.map(|mut pick| {
                 pick.autoderefs = step.autoderefs;
                 pick.autoref = Some(mutbl);
-                pick.unsize = step.unsize.to_option(self_ty);
+                pick.unsize = step.unsize.then_some(self_ty);
                 pick
             })
         })
diff --git a/src/librustc_typeck/check/upvar.rs b/src/librustc_typeck/check/upvar.rs
index fa5546d29c4..c5a6c072979 100644
--- a/src/librustc_typeck/check/upvar.rs
+++ b/src/librustc_typeck/check/upvar.rs
@@ -114,7 +114,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         };
 
         let infer_kind = if let UpvarSubsts::Closure(closure_substs) = substs {
-            self.closure_kind(closure_def_id, closure_substs).is_none().to_option(closure_substs)
+            self.closure_kind(closure_def_id, closure_substs).is_none().then_some(closure_substs)
         } else {
             None
         };
diff --git a/src/libsyntax/print/pprust.rs b/src/libsyntax/print/pprust.rs
index b0e13a508ee..b2e8d8526fd 100644
--- a/src/libsyntax/print/pprust.rs
+++ b/src/libsyntax/print/pprust.rs
@@ -317,7 +317,7 @@ pub fn token_to_string(token: &Token) -> String {
 }
 
 fn token_to_string_ext(token: &Token, convert_dollar_crate: bool) -> String {
-    let convert_dollar_crate = convert_dollar_crate.to_option(token.span);
+    let convert_dollar_crate = convert_dollar_crate.then_some(token.span);
     token_kind_to_string_ext(&token.kind, convert_dollar_crate)
 }
 
diff --git a/src/libsyntax_ext/format_foreign.rs b/src/libsyntax_ext/format_foreign.rs
index f6e8b086532..0d1d2926c85 100644
--- a/src/libsyntax_ext/format_foreign.rs
+++ b/src/libsyntax_ext/format_foreign.rs
@@ -95,12 +95,12 @@ pub mod printf {
             };
 
             // Has a special form in Rust for numbers.
-            let fill = c_zero.to_option("0");
+            let fill = c_zero.then_some("0");
 
-            let align = c_left.to_option("<");
+            let align = c_left.then_some("<");
 
             // Rust doesn't have an equivalent to the `' '` flag.
-            let sign = c_plus.to_option("+");
+            let sign = c_plus.then_some("+");
 
             // Not *quite* the same, depending on the type...
             let alt = c_alt;
diff --git a/src/libtest/lib.rs b/src/libtest/lib.rs
index 9ff9e382c88..2e90750b7a0 100644
--- a/src/libtest/lib.rs
+++ b/src/libtest/lib.rs
@@ -563,7 +563,7 @@ fn run_test_in_process(
         None
     };
 
-    let start = report_time.to_option(Instant::now());
+    let start = report_time.then_some(Instant::now());
     let result = catch_unwind(AssertUnwindSafe(testfn));
     let exec_time = start.map(|start| {
         let duration = start.elapsed();
@@ -594,7 +594,7 @@ fn spawn_test_subprocess(
         let args = env::args().collect::<Vec<_>>();
         let current_exe = &args[0];
 
-        let start = report_time.to_option(Instant::now());
+        let start = report_time.then_some(Instant::now());
         let output = match Command::new(current_exe)
             .env(SECONDARY_TEST_INVOKER_VAR, desc.name.as_slice())
             .output() {