if $c:expr { Some($r:expr) } else { None } =>> $c.then(|| $r)

compiler/rustc_ast_passes/src/ast_validation.rs

@@ -271,7 +271,7 @@ fn invalid_visibility(&self, vis: &Visibility, note: Option<InvalidVisibilityNot
 
         self.session.emit_err(InvalidVisibility {
             span: vis.span,
-            implied: if vis.kind.is_pub() { Some(vis.span) } else { None },
+            implied: vis.kind.is_pub().then(|| vis.span),
             note,
         });
     }

compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs

@@ -1186,11 +1186,7 @@ fn suggest_using_local_if_applicable(
                 return None;
             };
             debug!("checking call args for uses of inner_param: {:?}", args);
-            if args.contains(&Operand::Move(inner_param)) {
+            args.contains(&Operand::Move(inner_param)).then(|| (loc, term))
-                Some((loc, term))
-            } else {
-                None
-            }
         }) else {
             debug!("no uses of inner_param found as a by-move call arg");
             return;

compiler/rustc_borrowck/src/diagnostics/region_name.rs

@@ -280,17 +280,10 @@ fn give_name_from_error_region(&self, fr: RegionVid) -> Option<RegionName> {
 
         debug!("give_region_a_name: error_region = {:?}", error_region);
         match *error_region {
-            ty::ReEarlyBound(ebr) => {
+            ty::ReEarlyBound(ebr) => ebr.has_name().then(|| {
-                if ebr.has_name() {
+                let span = tcx.hir().span_if_local(ebr.def_id).unwrap_or(DUMMY_SP);
-                    let span = tcx.hir().span_if_local(ebr.def_id).unwrap_or(DUMMY_SP);
+                RegionName { name: ebr.name, source: RegionNameSource::NamedEarlyBoundRegion(span) }
-                    Some(RegionName {
+            }),
-                        name: ebr.name,
-                        source: RegionNameSource::NamedEarlyBoundRegion(span),
-                    })
-                } else {
-                    None
-                }
-            }
 
             ty::ReStatic => {
                 Some(RegionName { name: kw::StaticLifetime, source: RegionNameSource::Static })

compiler/rustc_borrowck/src/type_check/liveness/mod.rs

@@ -50,13 +50,11 @@ pub(super) fn generate<'mir, 'tcx>(
         compute_relevant_live_locals(typeck.tcx(), &free_regions, &body);
     let facts_enabled = use_polonius || AllFacts::enabled(typeck.tcx());
 
-    let polonius_drop_used = if facts_enabled {
+    let polonius_drop_used = facts_enabled.then(|| {
         let mut drop_used = Vec::new();
         polonius::populate_access_facts(typeck, body, location_table, move_data, &mut drop_used);
-        Some(drop_used)
+        drop_used
-    } else {
+    });
-        None
-    };
 
     trace::trace(
         typeck,

compiler/rustc_builtin_macros/src/deriving/debug.rs

@@ -135,19 +135,17 @@ fn expr_for_field(
         }
 
         // `let names: &'static _ = &["field1", "field2"];`
-        let names_let = if is_struct {
+        let names_let = is_struct.then(|| {
             let lt_static = Some(cx.lifetime_static(span));
             let ty_static_ref = cx.ty_ref(span, cx.ty_infer(span), lt_static, ast::Mutability::Not);
-            Some(cx.stmt_let_ty(
+            cx.stmt_let_ty(
                 span,
                 false,
                 Ident::new(sym::names, span),
                 Some(ty_static_ref),
                 cx.expr_array_ref(span, name_exprs),
-            ))
+            )
-        } else {
+        });
-            None
-        };
 
         // `let values: &[&dyn Debug] = &[&&self.field1, &&self.field2];`
         let path_debug = cx.path_global(span, cx.std_path(&[sym::fmt, sym::Debug]));

compiler/rustc_builtin_macros/src/deriving/generic/mod.rs

@@ -942,13 +942,11 @@ fn extract_arg_details(
         let mut nonself_arg_tys = Vec::new();
         let span = trait_.span;
 
-        let explicit_self = if self.explicit_self {
+        let explicit_self = self.explicit_self.then(|| {
             let (self_expr, explicit_self) = ty::get_explicit_self(cx, span);
             selflike_args.push(self_expr);
-            Some(explicit_self)
+            explicit_self
-        } else {
+        });
-            None
-        };
 
         for (ty, name) in self.nonself_args.iter() {
             let ast_ty = ty.to_ty(cx, span, type_ident, generics);

compiler/rustc_codegen_cranelift/src/driver/aot.rs

@@ -248,17 +248,13 @@ fn reuse_workproduct_for_cgu(
             dwarf_object: None,
             bytecode: None,
         },
-        module_global_asm: if has_global_asm {
+        module_global_asm: has_global_asm.then(|| CompiledModule {
-            Some(CompiledModule {
+            name: cgu.name().to_string(),
-                name: cgu.name().to_string(),
+            kind: ModuleKind::Regular,
-                kind: ModuleKind::Regular,
+            object: Some(obj_out_global_asm),
-                object: Some(obj_out_global_asm),
+            dwarf_object: None,
-                dwarf_object: None,
+            bytecode: None,
-                bytecode: None,
+        }),
-            })
-        } else {
-            None
-        },
         existing_work_product: Some((cgu.work_product_id(), work_product)),
     })
 }

compiler/rustc_codegen_llvm/src/back/write.rs

@@ -412,11 +412,7 @@ fn get_pgo_sample_use_path(config: &ModuleConfig) -> Option<CString> {
 }
 
 fn get_instr_profile_output_path(config: &ModuleConfig) -> Option<CString> {
-    if config.instrument_coverage {
+    config.instrument_coverage.then(|| CString::new("default_%m_%p.profraw").unwrap())
-        Some(CString::new("default_%m_%p.profraw").unwrap())
-    } else {
-        None
-    }
 }
 
 pub(crate) unsafe fn llvm_optimize(
@@ -451,11 +447,10 @@ pub(crate) unsafe fn llvm_optimize(
         None
     };
 
-    let mut llvm_profiler = if cgcx.prof.llvm_recording_enabled() {
+    let mut llvm_profiler = cgcx
-        Some(LlvmSelfProfiler::new(cgcx.prof.get_self_profiler().unwrap()))
+        .prof
-    } else {
+        .llvm_recording_enabled()
-        None
+        .then(|| LlvmSelfProfiler::new(cgcx.prof.get_self_profiler().unwrap()));
-    };
 
     let llvm_selfprofiler =
         llvm_profiler.as_mut().map(|s| s as *mut _ as *mut c_void).unwrap_or(std::ptr::null_mut());

compiler/rustc_codegen_llvm/src/context.rs

@@ -402,12 +402,8 @@ pub(crate) fn new(
 
         let (llcx, llmod) = (&*llvm_module.llcx, llvm_module.llmod());
 
-        let coverage_cx = if tcx.sess.instrument_coverage() {
+        let coverage_cx =
-            let covctx = coverageinfo::CrateCoverageContext::new();
+            tcx.sess.instrument_coverage().then(coverageinfo::CrateCoverageContext::new);
-            Some(covctx)
-        } else {
-            None
-        };
 
         let dbg_cx = if tcx.sess.opts.debuginfo != DebugInfo::None {
             let dctx = debuginfo::CodegenUnitDebugContext::new(llmod);

compiler/rustc_codegen_llvm/src/type_of.rs

@@ -154,7 +154,7 @@ fn struct_llfields<'a, 'tcx>(
     } else {
         debug!("struct_llfields: offset: {:?} stride: {:?}", offset, layout.size);
     }
-    let field_remapping = if padding_used { Some(field_remapping) } else { None };
+    let field_remapping = padding_used.then(|| field_remapping);
     (result, packed, field_remapping)
 }
 

compiler/rustc_codegen_ssa/src/base.rs

@@ -579,7 +579,7 @@ pub fn codegen_crate<B: ExtraBackendMethods>(
         }
     }
 
-    let metadata_module = if need_metadata_module {
+    let metadata_module = need_metadata_module.then(|| {
         // Emit compressed metadata object.
         let metadata_cgu_name =
             cgu_name_builder.build_cgu_name(LOCAL_CRATE, &["crate"], Some("metadata")).to_string();
@@ -594,17 +594,15 @@ pub fn codegen_crate<B: ExtraBackendMethods>(
             if let Err(error) = std::fs::write(&file_name, data) {
                 tcx.sess.emit_fatal(errors::MetadataObjectFileWrite { error });
             }
-            Some(CompiledModule {
+            CompiledModule {
                 name: metadata_cgu_name,
                 kind: ModuleKind::Metadata,
                 object: Some(file_name),
                 dwarf_object: None,
                 bytecode: None,
-            })
+            }
         })
-    } else {
+    });
-        None
-    };
 
     let ongoing_codegen = start_async_codegen(
         backend.clone(),

compiler/rustc_codegen_ssa/src/mir/mod.rs

@@ -167,8 +167,7 @@ pub fn codegen_mir<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
         start_bx.set_personality_fn(cx.eh_personality());
     }
 
-    let cleanup_kinds =
+    let cleanup_kinds = base::wants_msvc_seh(cx.tcx().sess).then(|| analyze::cleanup_kinds(&mir));
-        if base::wants_msvc_seh(cx.tcx().sess) { Some(analyze::cleanup_kinds(&mir)) } else { None };
 
     let cached_llbbs: IndexVec<mir::BasicBlock, CachedLlbb<Bx::BasicBlock>> =
         mir.basic_blocks

compiler/rustc_data_structures/src/profiling.rs

@@ -207,8 +207,7 @@ fn cold_call<F>(profiler_ref: &SelfProfilerRef, f: F) -> TimingGuard<'_>
     /// a measureme event, "verbose" generic activities also print a timing entry to
     /// stderr if the compiler is invoked with -Ztime-passes.
     pub fn verbose_generic_activity(&self, event_label: &'static str) -> VerboseTimingGuard<'_> {
-        let message =
+        let message = self.print_verbose_generic_activities.then(|| event_label.to_owned());
-            if self.print_verbose_generic_activities { Some(event_label.to_owned()) } else { None };
 
         VerboseTimingGuard::start(message, self.generic_activity(event_label))
     }
@@ -222,11 +221,9 @@ pub fn verbose_generic_activity_with_arg<A>(
     where
         A: Borrow<str> + Into<String>,
     {
-        let message = if self.print_verbose_generic_activities {
+        let message = self
-            Some(format!("{}({})", event_label, event_arg.borrow()))
+            .print_verbose_generic_activities
-        } else {
+            .then(|| format!("{}({})", event_label, event_arg.borrow()));
-            None
-        };
 
         VerboseTimingGuard::start(message, self.generic_activity_with_arg(event_label, event_arg))
     }

compiler/rustc_errors/src/lib.rs

@@ -1066,29 +1066,26 @@ pub fn err_count(&self) -> usize {
     }
 
     pub fn has_errors(&self) -> Option<ErrorGuaranteed> {
-        if self.inner.borrow().has_errors() { Some(ErrorGuaranteed(())) } else { None }
+        self.inner.borrow().has_errors().then(ErrorGuaranteed::unchecked_claim_error_was_emitted)
     }
 
     pub fn has_errors_or_lint_errors(&self) -> Option<ErrorGuaranteed> {
-        if self.inner.borrow().has_errors_or_lint_errors() {
+        self.inner
-            Some(ErrorGuaranteed::unchecked_claim_error_was_emitted())
+            .borrow()
-        } else {
+            .has_errors_or_lint_errors()
-            None
+            .then(ErrorGuaranteed::unchecked_claim_error_was_emitted)
-        }
     }
     pub fn has_errors_or_delayed_span_bugs(&self) -> Option<ErrorGuaranteed> {
-        if self.inner.borrow().has_errors_or_delayed_span_bugs() {
+        self.inner
-            Some(ErrorGuaranteed::unchecked_claim_error_was_emitted())
+            .borrow()
-        } else {
+            .has_errors_or_delayed_span_bugs()
-            None
+            .then(ErrorGuaranteed::unchecked_claim_error_was_emitted)
-        }
     }
     pub fn is_compilation_going_to_fail(&self) -> Option<ErrorGuaranteed> {
-        if self.inner.borrow().is_compilation_going_to_fail() {
+        self.inner
-            Some(ErrorGuaranteed::unchecked_claim_error_was_emitted())
+            .borrow()
-        } else {
+            .is_compilation_going_to_fail()
-            None
+            .then(ErrorGuaranteed::unchecked_claim_error_was_emitted)
-        }
     }
 
     pub fn print_error_count(&self, registry: &Registry) {

compiler/rustc_expand/src/config.rs

@@ -238,12 +238,10 @@ macro_rules! configure {
 impl<'a> StripUnconfigured<'a> {
     pub fn configure<T: HasAttrs + HasTokens>(&self, mut node: T) -> Option<T> {
         self.process_cfg_attrs(&mut node);
-        if self.in_cfg(node.attrs()) {
+        self.in_cfg(node.attrs()).then(|| {
             self.try_configure_tokens(&mut node);
-            Some(node)
+            node
-        } else {
+        })
-            None
-        }
     }
 
     fn try_configure_tokens<T: HasTokens>(&self, node: &mut T) {
@@ -257,7 +255,7 @@ fn try_configure_tokens<T: HasTokens>(&self, node: &mut T) {
 
     fn configure_krate_attrs(&self, mut attrs: ast::AttrVec) -> Option<ast::AttrVec> {
         attrs.flat_map_in_place(|attr| self.process_cfg_attr(attr));
-        if self.in_cfg(&attrs) { Some(attrs) } else { None }
+        self.in_cfg(&attrs).then(|| attrs)
     }
 
     /// Performs cfg-expansion on `stream`, producing a new `AttrTokenStream`.

compiler/rustc_hir/src/hir.rs

@@ -574,14 +574,11 @@ pub fn span_for_lifetime_suggestion(&self) -> Option<Span> {
 
     /// If there are generic parameters, return where to introduce a new one.
     pub fn span_for_param_suggestion(&self) -> Option<Span> {
-        if self.params.iter().any(|p| self.span.contains(p.span)) {
+        self.params.iter().any(|p| self.span.contains(p.span)).then(|| {
             // `fn foo<A>(t: impl Trait)`
             //          ^ suggest `, T: Trait` here
-            let span = self.span.with_lo(self.span.hi() - BytePos(1)).shrink_to_lo();
+            self.span.with_lo(self.span.hi() - BytePos(1)).shrink_to_lo()
-            Some(span)
+        })
-        } else {
-            None
-        }
     }
 
     /// `Span` where further predicates would be suggested, accounting for trailing commas, like
@@ -639,7 +636,7 @@ pub fn bounds_span_for_suggestions(&self, param_def_id: LocalDefId) -> Option<Sp
                 // We include bounds that come from a `#[derive(_)]` but point at the user's code,
                 // as we use this method to get a span appropriate for suggestions.
                 let bs = bound.span();
-                if bs.can_be_used_for_suggestions() { Some(bs.shrink_to_hi()) } else { None }
+                bs.can_be_used_for_suggestions().then(|| bs.shrink_to_hi())
             },
         )
     }

compiler/rustc_hir_analysis/src/collect/type_of.rs

@@ -259,13 +259,8 @@ pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: DefId) -> Ty<'_> {
             }
             TraitItemKind::Const(ty, body_id) => body_id
                 .and_then(|body_id| {
-                    if is_suggestable_infer_ty(ty) {
+                    is_suggestable_infer_ty(ty)
-                        Some(infer_placeholder_type(
+                        .then(|| infer_placeholder_type(tcx, def_id, body_id, ty.span, item.ident, "constant",))
-                            tcx, def_id, body_id, ty.span, item.ident, "constant",
-                        ))
-                    } else {
-                        None
-                    }
                 })
                 .unwrap_or_else(|| icx.to_ty(ty)),
             TraitItemKind::Type(_, Some(ty)) => icx.to_ty(ty),

compiler/rustc_hir_typeck/src/check.rs

@@ -74,15 +74,13 @@ pub(super) fn check_fn<'a, 'tcx>(
 
     // C-variadic fns also have a `VaList` input that's not listed in `fn_sig`
     // (as it's created inside the body itself, not passed in from outside).
-    let maybe_va_list = if fn_sig.c_variadic {
+    let maybe_va_list = fn_sig.c_variadic.then(|| {
         let span = body.params.last().unwrap().span;
         let va_list_did = tcx.require_lang_item(LangItem::VaList, Some(span));
         let region = fcx.next_region_var(RegionVariableOrigin::MiscVariable(span));
 
-        Some(tcx.bound_type_of(va_list_did).subst(tcx, &[region.into()]))
+        tcx.bound_type_of(va_list_did).subst(tcx, &[region.into()])
-    } else {
+    });
-        None
-    };
 
     // Add formal parameters.
     let inputs_hir = hir.fn_decl_by_hir_id(fn_id).map(|decl| &decl.inputs);

compiler/rustc_hir_typeck/src/generator_interior/mod.rs

@@ -274,12 +274,10 @@ pub fn resolve_interior<'a, 'tcx>(
                 let r = fcx.tcx.mk_region(ty::ReLateBound(current_depth, br));
                 r
             });
-            if captured_tys.insert(ty) {
+            captured_tys.insert(ty).then(|| {
                 cause.ty = ty;
-                Some(cause)
+                cause
-            } else {
+            })
-                None
-            }
         })
         .collect();
 

compiler/rustc_infer/src/infer/error_reporting/nice_region_error/util.rs

@@ -90,20 +90,18 @@ pub fn find_param_with_region<'tcx>(
                     r
                 }
             });
-            if found_anon_region {
+            found_anon_region.then(|| {
                 let ty_hir_id = fn_decl.inputs[index].hir_id;
                 let param_ty_span = hir.span(ty_hir_id);
                 let is_first = index == 0;
-                Some(AnonymousParamInfo {
+                AnonymousParamInfo {
                     param,
                     param_ty: new_param_ty,
                     param_ty_span,
                     bound_region,
                     is_first,
-                })
+                }
-            } else {
+            })
-                None
-            }
         })
 }
 

compiler/rustc_lint/src/builtin.rs

@@ -2308,11 +2308,7 @@ fn check_crate(&mut self, cx: &EarlyContext<'_>, _: &ast::Crate) {
             .for_each(|(&name, &span)| {
                 let note = rustc_feature::find_feature_issue(name, GateIssue::Language)
                     .map(|n| BuiltinIncompleteFeaturesNote { n });
-                let help = if HAS_MIN_FEATURES.contains(&name) {
+                let help = HAS_MIN_FEATURES.contains(&name).then(|| BuiltinIncompleteFeaturesHelp);
-                    Some(BuiltinIncompleteFeaturesHelp)
-                } else {
-                    None
-                };
                 cx.emit_spanned_lint(
                     INCOMPLETE_FEATURES,
                     span,

compiler/rustc_lint/src/context.rs

@@ -487,7 +487,7 @@ fn no_lint_suggestion(&self, lint_name: &str) -> CheckLintNameResult<'_> {
         let mut groups: Vec<_> = self
             .lint_groups
             .iter()
-            .filter_map(|(k, LintGroup { depr, .. })| if depr.is_none() { Some(k) } else { None })
+            .filter_map(|(k, LintGroup { depr, .. })| depr.is_none().then(|| k))
             .collect();
         groups.sort();
         let groups = groups.iter().map(|k| Symbol::intern(k));
@@ -1112,11 +1112,9 @@ pub fn qpath_res(&self, qpath: &hir::QPath<'_>, id: hir::HirId) -> Res {
                 .maybe_typeck_results()
                 .filter(|typeck_results| typeck_results.hir_owner == id.owner)
                 .or_else(|| {
-                    if self.tcx.has_typeck_results(id.owner.to_def_id()) {
+                    self.tcx
-                        Some(self.tcx.typeck(id.owner.def_id))
+                        .has_typeck_results(id.owner.to_def_id())
-                    } else {
+                        .then(|| self.tcx.typeck(id.owner.def_id))
-                        None
-                    }
                 })
                 .and_then(|typeck_results| typeck_results.type_dependent_def(id))
                 .map_or(Res::Err, |(kind, def_id)| Res::Def(kind, def_id)),

compiler/rustc_lint/src/for_loops_over_fallibles.rs

@@ -65,11 +65,8 @@ fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
             } else {
                 ForLoopsOverFalliblesLoopSub::UseWhileLet { start_span: expr.span.with_hi(pat.span.lo()), end_span: pat.span.between(arg.span), var }
             } ;
-        let question_mark = if suggest_question_mark(cx, adt, substs, expr.span) {
+        let question_mark = suggest_question_mark(cx, adt, substs, expr.span)
-            Some(ForLoopsOverFalliblesQuestionMark { suggestion: arg.span.shrink_to_hi() })
+            .then(|| ForLoopsOverFalliblesQuestionMark { suggestion: arg.span.shrink_to_hi() });
-        } else {
-            None
-        };
         let suggestion = ForLoopsOverFalliblesSuggestion {
             var,
             start_span: expr.span.with_hi(pat.span.lo()),

compiler/rustc_middle/src/hir/map/mod.rs

@@ -1062,7 +1062,7 @@ pub fn span_with_body(self, hir_id: HirId) -> Span {
     }
 
     pub fn span_if_local(self, id: DefId) -> Option<Span> {
-        if id.is_local() { Some(self.tcx.def_span(id)) } else { None }
+        id.is_local().then(|| self.tcx.def_span(id))
     }
 
     pub fn res_span(self, res: Res) -> Option<Span> {

compiler/rustc_middle/src/ty/context.rs

@@ -1113,13 +1113,11 @@ pub fn return_type_impl_trait(self, scope_def_id: LocalDefId) -> Option<(Ty<'tcx
             ty::FnDef(_, _) => {
                 let sig = ret_ty.fn_sig(self);
                 let output = self.erase_late_bound_regions(sig.output());
-                if output.is_impl_trait() {
+                output.is_impl_trait().then(|| {
                     let hir_id = self.hir().local_def_id_to_hir_id(scope_def_id);
                     let fn_decl = self.hir().fn_decl_by_hir_id(hir_id).unwrap();
-                    Some((output, fn_decl.output.span()))
+                    (output, fn_decl.output.span())
-                } else {
+                })
-                    None
-                }
             }
             _ => None,
         }
@@ -1225,13 +1223,12 @@ macro_rules! nop_lift {
         impl<'a, 'tcx> Lift<'tcx> for $ty {
             type Lifted = $lifted;
             fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
-                if tcx.interners.$set.contains_pointer_to(&InternedInSet(&*self.0.0)) {
+                tcx.interners
+                    .$set
+                    .contains_pointer_to(&InternedInSet(&*self.0.0))
                     // SAFETY: `self` is interned and therefore valid
                     // for the entire lifetime of the `TyCtxt`.
-                    Some(unsafe { mem::transmute(self) })
+                    .then(|| unsafe { mem::transmute(self) })
-                } else {
-                    None
-                }
             }
         }
     };
@@ -1246,13 +1243,13 @@ fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
         if self.is_empty() {
             return Some(List::empty());
         }
-        if tcx.interners.substs.contains_pointer_to(&InternedInSet(self.as_substs())) {
+
+        tcx.interners
+            .substs
+            .contains_pointer_to(&InternedInSet(self.as_substs()))
             // SAFETY: `self` is interned and therefore valid
             // for the entire lifetime of the `TyCtxt`.
-            Some(unsafe { mem::transmute::<&'a List<Ty<'a>>, &'tcx List<Ty<'tcx>>>(self) })
+            .then(|| unsafe { mem::transmute::<&'a List<Ty<'a>>, &'tcx List<Ty<'tcx>>>(self) })
-        } else {
-            None
-        }
     }
 }
 
@@ -1264,11 +1261,10 @@ fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
                 if self.is_empty() {
                     return Some(List::empty());
                 }
-                if tcx.interners.$set.contains_pointer_to(&InternedInSet(self)) {
+                tcx.interners
-                    Some(unsafe { mem::transmute(self) })
+                    .$set
-                } else {
+                    .contains_pointer_to(&InternedInSet(self))
-                    None
+                    .then(|| unsafe { mem::transmute(self) })
-                }
             }
         }
     };

compiler/rustc_middle/src/ty/instance.rs

@@ -584,7 +584,7 @@ pub fn fn_once_adapter_instance(
     /// this function returns `None`, then the MIR body does not require substitution during
     /// codegen.
     fn substs_for_mir_body(&self) -> Option<SubstsRef<'tcx>> {
-        if self.def.has_polymorphic_mir_body() { Some(self.substs) } else { None }
+        self.def.has_polymorphic_mir_body().then(|| self.substs)
     }
 
     pub fn subst_mir<T>(&self, tcx: TyCtxt<'tcx>, v: &T) -> T

compiler/rustc_middle/src/ty/subst.rs

@@ -267,13 +267,11 @@ fn decode(d: &mut D) -> GenericArg<'tcx> {
 impl<'tcx> InternalSubsts<'tcx> {
     /// Checks whether all elements of this list are types, if so, transmute.
     pub fn try_as_type_list(&'tcx self) -> Option<&'tcx List<Ty<'tcx>>> {
-        if self.iter().all(|arg| matches!(arg.unpack(), GenericArgKind::Type(_))) {
+        self.iter().all(|arg| matches!(arg.unpack(), GenericArgKind::Type(_))).then(|| {
             assert_eq!(TYPE_TAG, 0);
             // SAFETY: All elements are types, see `List<Ty<'tcx>>::as_substs`.
-            Some(unsafe { &*(self as *const List<GenericArg<'tcx>> as *const List<Ty<'tcx>>) })
+            unsafe { &*(self as *const List<GenericArg<'tcx>> as *const List<Ty<'tcx>>) }
-        } else {
+        })
-            None
-        }
     }
 
     /// Interpret these substitutions as the substitutions of a closure type.

compiler/rustc_mir_build/src/build/expr/into.rs

@@ -319,7 +319,7 @@ pub(crate) fn expr_into_dest(
                 // See the notes for `ExprKind::Array` in `as_rvalue` and for
                 // `ExprKind::Borrow` above.
                 let is_union = adt_def.is_union();
-                let active_field_index = if is_union { Some(fields[0].name.index()) } else { None };
+                let active_field_index = is_union.then(|| fields[0].name.index());
 
                 let scope = this.local_scope();
 

compiler/rustc_mir_build/src/build/matches/test.rs

@@ -563,14 +563,11 @@ pub(super) fn sort_candidate<'pat>(
                 let not_contained =
                     self.values_not_contained_in_range(&*range, options).unwrap_or(false);
 
-                if not_contained {
+                not_contained.then(|| {
                     // No switch values are contained in the pattern range,
                     // so the pattern can be matched only if this test fails.
-                    let otherwise = options.len();
+                    options.len()
-                    Some(otherwise)
+                })
-                } else {
-                    None
-                }
             }
 
             (&TestKind::SwitchInt { .. }, _) => None,

compiler/rustc_mir_build/src/thir/pattern/deconstruct_pat.rs

@@ -172,7 +172,7 @@ fn from_range<'tcx>(
         ty: Ty<'tcx>,
         end: &RangeEnd,
     ) -> Option<IntRange> {
-        if Self::is_integral(ty) {
+        Self::is_integral(ty).then(|| {
             // Perform a shift if the underlying types are signed,
             // which makes the interval arithmetic simpler.
             let bias = IntRange::signed_bias(tcx, ty);
@@ -182,10 +182,8 @@ fn from_range<'tcx>(
                 // This should have been caught earlier by E0030.
                 bug!("malformed range pattern: {}..={}", lo, (hi - offset));
             }
-            Some(IntRange { range: lo..=(hi - offset), bias })
+            IntRange { range: lo..=(hi - offset), bias }
-        } else {
+        })
-            None
-        }
     }
 
     // The return value of `signed_bias` should be XORed with an endpoint to encode/decode it.

compiler/rustc_mir_build/src/thir/pattern/mod.rs

@@ -203,11 +203,7 @@ fn lower_pattern_range(
                 if !lower_overflow && !higher_overflow {
                     self.tcx.sess.emit_err(LowerRangeBoundMustBeLessThanOrEqualToUpper {
                         span,
-                        teach: if self.tcx.sess.teach(&error_code!(E0030)) {
+                        teach: self.tcx.sess.teach(&error_code!(E0030)).then(|| ()),
-                            Some(())
-                        } else {
-                            None
-                        },
                     });
                 }
                 PatKind::Wild

compiler/rustc_mir_dataflow/src/impls/liveness.rs

@@ -254,13 +254,7 @@ fn apply_statement_effect(
     ) {
         // Compute the place that we are storing to, if any
         let destination = match &statement.kind {
-            StatementKind::Assign(assign) => {
+            StatementKind::Assign(assign) => assign.1.is_safe_to_remove().then(|| assign.0),
-                if assign.1.is_safe_to_remove() {
-                    Some(assign.0)
-                } else {
-                    None
-                }
-            }
             StatementKind::SetDiscriminant { place, .. } | StatementKind::Deinit(place) => {
                 Some(**place)
             }

compiler/rustc_mir_transform/src/function_item_references.rs

@@ -111,11 +111,9 @@ fn check_bound_args(
     /// If the given predicate is the trait `fmt::Pointer`, returns the bound parameter type.
     fn is_pointer_trait(&self, bound: &PredicateKind<'tcx>) -> Option<Ty<'tcx>> {
         if let ty::PredicateKind::Clause(ty::Clause::Trait(predicate)) = bound {
-            if self.tcx.is_diagnostic_item(sym::Pointer, predicate.def_id()) {
+            self.tcx
-                Some(predicate.trait_ref.self_ty())
+                .is_diagnostic_item(sym::Pointer, predicate.def_id())
-            } else {
+                .then(|| predicate.trait_ref.self_ty())
-                None
-            }
         } else {
             None
         }

compiler/rustc_parse/src/parser/mod.rs

@@ -1283,22 +1283,16 @@ fn parse_attr_args(&mut self) -> PResult<'a, AttrArgs> {
     }
 
     fn parse_delim_args_inner(&mut self) -> Option<DelimArgs> {
-        if self.check(&token::OpenDelim(Delimiter::Parenthesis))
+        let delimited = self.check(&token::OpenDelim(Delimiter::Parenthesis))
             || self.check(&token::OpenDelim(Delimiter::Bracket))
-            || self.check(&token::OpenDelim(Delimiter::Brace))
+            || self.check(&token::OpenDelim(Delimiter::Brace));
-        {
+
-            match self.parse_token_tree() {
+        delimited.then(|| {
-                // We've confirmed above that there is a delimiter so unwrapping is OK.
+            // We've confirmed above that there is a delimiter so unwrapping is OK.
-                TokenTree::Delimited(dspan, delim, tokens) => Some(DelimArgs {
+            let TokenTree::Delimited(dspan, delim, tokens) = self.parse_token_tree() else { unreachable!() };
-                    dspan,
+
-                    delim: MacDelimiter::from_token(delim).unwrap(),
+            DelimArgs { dspan, delim: MacDelimiter::from_token(delim).unwrap(), tokens }
-                    tokens,
+        })
-                }),
-                _ => unreachable!(),
-            }
-        } else {
-            None
-        }
     }
 
     fn parse_or_use_outer_attributes(

compiler/rustc_parse/src/parser/path.rs

@@ -404,7 +404,7 @@ fn parse_angle_args_with_leading_angle_bracket_recovery(
 
         let is_first_invocation = style == PathStyle::Expr;
         // Take a snapshot before attempting to parse - we can restore this later.
-        let snapshot = if is_first_invocation { Some(self.clone()) } else { None };
+        let snapshot = is_first_invocation.then(|| self.clone());
 
         debug!("parse_generic_args_with_leading_angle_bracket_recovery: (snapshotting)");
         match self.parse_angle_args(ty_generics) {

compiler/rustc_parse/src/parser/ty.rs

@@ -450,8 +450,7 @@ fn parse_array_or_slice_ty(&mut self) -> PResult<'a, TyKind> {
 
     fn parse_borrowed_pointee(&mut self) -> PResult<'a, TyKind> {
         let and_span = self.prev_token.span;
-        let mut opt_lifetime =
+        let mut opt_lifetime = self.check_lifetime().then(|| self.expect_lifetime());
-            if self.check_lifetime() { Some(self.expect_lifetime()) } else { None };
         let mut mutbl = self.parse_mutability();
         if self.token.is_lifetime() && mutbl == Mutability::Mut && opt_lifetime.is_none() {
             // A lifetime is invalid here: it would be part of a bare trait bound, which requires
@@ -871,7 +870,7 @@ fn parse_ty_bound_modifiers(&mut self) -> PResult<'a, BoundModifiers> {
             None
         };
 
-        let maybe = if self.eat(&token::Question) { Some(self.prev_token.span) } else { None };
+        let maybe = self.eat(&token::Question).then(|| self.prev_token.span);
 
         Ok(BoundModifiers { maybe, maybe_const })
     }

compiler/rustc_parse_format/src/lib.rs

@@ -835,7 +835,7 @@ fn integer(&mut self) -> Option<usize> {
             );
         }
 
-        if found { Some(cur) } else { None }
+        found.then(|| cur)
     }
 
     fn suggest_format(&mut self) {

compiler/rustc_passes/src/diagnostic_items.rs

@@ -32,11 +32,8 @@ fn collect_item(tcx: TyCtxt<'_>, items: &mut DiagnosticItems, name: Symbol, item
     if let Some(original_def_id) = items.name_to_id.insert(name, item_def_id) {
         if original_def_id != item_def_id {
             let orig_span = tcx.hir().span_if_local(original_def_id);
-            let orig_crate_name = if orig_span.is_some() {
+            let orig_crate_name =
-                None
+                orig_span.is_none().then(|| tcx.crate_name(original_def_id.krate));
-            } else {
-                Some(tcx.crate_name(original_def_id.krate))
-            };
             match tcx.hir().span_if_local(item_def_id) {
                 Some(span) => tcx.sess.emit_err(DuplicateDiagnosticItem { span, name }),
                 None => tcx.sess.emit_err(DuplicateDiagnosticItemInCrate {

compiler/rustc_passes/src/stability.rs

@@ -281,7 +281,7 @@ fn annotate<F>(
         self.recurse_with_stability_attrs(
             depr.map(|(d, _)| DeprecationEntry::local(d, def_id)),
             stab,
-            if inherit_const_stability.yes() { const_stab } else { None },
+            inherit_const_stability.yes().then(|| const_stab).flatten(),
             visit_children,
         );
     }

compiler/rustc_query_system/src/dep_graph/serialized.rs

@@ -242,8 +242,7 @@ pub fn new(
         record_graph: bool,
         record_stats: bool,
     ) -> Self {
-        let record_graph =
+        let record_graph = record_graph.then(|| Lock::new(DepGraphQuery::new(prev_node_count)));
-            if record_graph { Some(Lock::new(DepGraphQuery::new(prev_node_count))) } else { None };
         let status = Lock::new(EncoderState::new(encoder, record_stats));
         GraphEncoder { status, record_graph }
     }

compiler/rustc_resolve/src/late/diagnostics.rs

@@ -1700,11 +1700,9 @@ fn lookup_typo_candidate(
                                         let crate_mod =
                                             Res::Def(DefKind::Mod, crate_id.as_def_id());
 
-                                        if filter_fn(crate_mod) {
+                                        filter_fn(crate_mod).then(|| {
-                                            Some(TypoSuggestion::typo_from_ident(*ident, crate_mod))
+                                            TypoSuggestion::typo_from_ident(*ident, crate_mod)
-                                        } else {
+                                        })
-                                            None
-                                        }
                                     })
                             }));
 

compiler/rustc_session/src/config.rs

@@ -2544,7 +2544,7 @@ pub fn build_session_options(matches: &getopts::Matches) -> Options {
         }
 
         // Only use this directory if it has a file we can expect to always find.
-        if candidate.join("library/std/src/lib.rs").is_file() { Some(candidate) } else { None }
+        candidate.join("library/std/src/lib.rs").is_file().then(|| candidate)
     };
 
     let working_dir = std::env::current_dir().unwrap_or_else(|e| {

compiler/rustc_session/src/errors.rs

@@ -322,11 +322,7 @@ fn fix_base_capitalisation(prefix: &str, suffix: &str) -> Option<String> {
                 .take_while(|c| *c != 'i' && *c != 'u')
                 .all(|c| c.to_digit(base).is_some());
 
-        if valid {
+        valid.then(|| format!("0{}{}", base_char.to_ascii_lowercase(), &suffix[1..]))
-            Some(format!("0{}{}", base_char.to_ascii_lowercase(), &suffix[1..]))
-        } else {
-            None
-        }
     }
 
     let token::Lit { kind, symbol, suffix, .. } = lit;

compiler/rustc_session/src/filesearch.rs

@@ -217,7 +217,7 @@ fn from_env_args_next() -> Option<PathBuf> {
                 // Look for the target rustlib directory in the suspected sysroot.
                 let mut rustlib_path = rustc_target::target_rustlib_path(&p, "dummy");
                 rustlib_path.pop(); // pop off the dummy target.
-                if rustlib_path.exists() { Some(p) } else { None }
+                rustlib_path.exists().then(|| p)
             }
             None => None,
         }

compiler/rustc_session/src/options.rs

@@ -809,7 +809,7 @@ pub(crate) fn parse_mir_spanview(slot: &mut Option<MirSpanview>, v: Option<&str>
         if v.is_some() {
             let mut bool_arg = None;
             if parse_opt_bool(&mut bool_arg, v) {
-                *slot = if bool_arg.unwrap() { Some(MirSpanview::Statement) } else { None };
+                *slot = bool_arg.unwrap().then(|| MirSpanview::Statement);
                 return true;
             }
         }
@@ -850,7 +850,7 @@ pub(crate) fn parse_instrument_coverage(
         if v.is_some() {
             let mut bool_arg = None;
             if parse_opt_bool(&mut bool_arg, v) {
-                *slot = if bool_arg.unwrap() { Some(InstrumentCoverage::All) } else { None };
+                *slot = bool_arg.unwrap().then(|| InstrumentCoverage::All);
                 return true;
             }
         }

compiler/rustc_span/src/def_id.rs

@@ -299,7 +299,7 @@ pub fn is_local(self) -> bool {
 
     #[inline]
     pub fn as_local(self) -> Option<LocalDefId> {
-        if self.is_local() { Some(LocalDefId { local_def_index: self.index }) } else { None }
+        self.is_local().then(|| LocalDefId { local_def_index: self.index })
     }
 
     #[inline]
@@ -320,7 +320,7 @@ pub fn is_crate_root(self) -> bool {
 
     #[inline]
     pub fn as_crate_root(self) -> Option<CrateNum> {
-        if self.is_crate_root() { Some(self.krate) } else { None }
+        self.is_crate_root().then(|| self.krate)
     }
 
     #[inline]

compiler/rustc_symbol_mangling/src/lib.rs

@@ -244,8 +244,7 @@ fn compute_symbol_name<'tcx>(
     // project.
     let avoid_cross_crate_conflicts = is_generic(substs) || is_globally_shared_function;
 
-    let instantiating_crate =
+    let instantiating_crate = avoid_cross_crate_conflicts.then(compute_instantiating_crate);
-        if avoid_cross_crate_conflicts { Some(compute_instantiating_crate()) } else { None };
 
     // Pick the crate responsible for the symbol mangling version, which has to:
     // 1. be stable for each instance, whether it's being defined or imported

compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs

@@ -82,11 +82,8 @@ fn try_get_upvar_span<F>(
                     upvars.iter().find_map(|(upvar_id, upvar)| {
                         let upvar_ty = typeck_results.node_type(*upvar_id);
                         let upvar_ty = infer_context.resolve_vars_if_possible(upvar_ty);
-                        if ty_matches(ty::Binder::dummy(upvar_ty)) {
+                        ty_matches(ty::Binder::dummy(upvar_ty))
-                            Some(GeneratorInteriorOrUpvar::Upvar(upvar.span))
+                            .then(|| GeneratorInteriorOrUpvar::Upvar(upvar.span))
-                        } else {
-                            None
-                        }
                     })
                 })
             }
@@ -770,15 +767,13 @@ fn suggest_dereferences(
                             obligation.param_env,
                             real_trait_pred_and_ty,
                         );
-                        if obligations
+                        let may_hold = obligations
                             .iter()
                             .chain([&obligation])
                             .all(|obligation| self.predicate_may_hold(obligation))
-                        {
+                            .then(|| steps);
-                            Some(steps)
+
-                        } else {
+                        may_hold
-                            None
-                        }
                     })
                 {
                     if steps > 0 {

compiler/rustc_trait_selection/src/traits/mod.rs

@@ -523,16 +523,14 @@ fn visit_const(&mut self, ct: ty::Const<'tcx>) -> ControlFlow<Self::BreakTy> {
 
     let mut visitor = ReferencesOnlyParentGenerics { tcx, generics, trait_item_def_id };
     let predicates_for_trait = predicates.predicates.iter().filter_map(|(pred, span)| {
-        if pred.visit_with(&mut visitor).is_continue() {
+        pred.visit_with(&mut visitor).is_continue().then(|| {
-            Some(Obligation::new(
+            Obligation::new(
                 tcx,
                 ObligationCause::dummy_with_span(*span),
                 param_env,
                 ty::EarlyBinder(*pred).subst(tcx, impl_trait_ref.substs),
-            ))
+            )
-        } else {
+        })
-            None
-        }
     });
 
     let infcx = tcx.infer_ctxt().ignoring_regions().build();

compiler/rustc_trait_selection/src/traits/object_safety.rs

@@ -307,7 +307,7 @@ fn predicate_references_self<'tcx>(
     match predicate.kind().skip_binder() {
         ty::PredicateKind::Clause(ty::Clause::Trait(ref data)) => {
             // In the case of a trait predicate, we can skip the "self" type.
-            if data.trait_ref.substs[1..].iter().any(has_self_ty) { Some(sp) } else { None }
+            data.trait_ref.substs[1..].iter().any(has_self_ty).then(|| sp)
         }
         ty::PredicateKind::Clause(ty::Clause::Projection(ref data)) => {
             // And similarly for projections. This should be redundant with
@@ -325,7 +325,7 @@ fn predicate_references_self<'tcx>(
             //
             // This is ALT2 in issue #56288, see that for discussion of the
             // possible alternatives.
-            if data.projection_ty.substs[1..].iter().any(has_self_ty) { Some(sp) } else { None }
+            data.projection_ty.substs[1..].iter().any(has_self_ty).then(|| sp)
         }
         ty::PredicateKind::AliasEq(..) => bug!("`AliasEq` not allowed as assumption"),
 

compiler/rustc_trait_selection/src/traits/query/type_op/outlives.rs

@@ -21,11 +21,7 @@ fn try_fast_path(
         tcx: TyCtxt<'tcx>,
         key: &ParamEnvAnd<'tcx, Self>,
     ) -> Option<Self::QueryResponse> {
-        if trivial_dropck_outlives(tcx, key.value.dropped_ty) {
+        trivial_dropck_outlives(tcx, key.value.dropped_ty).then(DropckOutlivesResult::default)
-            Some(DropckOutlivesResult::default())
-        } else {
-            None
-        }
     }
 
     fn perform_query(

compiler/rustc_trait_selection/src/traits/select/mod.rs

@@ -378,11 +378,8 @@ fn candidate_from_obligation_no_cache<'o>(
                             let self_ty = trait_ref.self_ty();
                             let (trait_desc, self_desc) = with_no_trimmed_paths!({
                                 let trait_desc = trait_ref.print_only_trait_path().to_string();
-                                let self_desc = if self_ty.has_concrete_skeleton() {
+                                let self_desc =
-                                    Some(self_ty.to_string())
+                                    self_ty.has_concrete_skeleton().then(|| self_ty.to_string());
-                                } else {
-                                    None
-                                };
                                 (trait_desc, self_desc)
                             });
                             let cause = if let Conflict::Upstream = conflict {

compiler/rustc_trait_selection/src/traits/specialize/specialization_graph.rs

@@ -113,7 +113,7 @@ fn insert(
                     // Only report the `Self` type if it has at least
                     // some outer concrete shell; otherwise, it's
                     // not adding much information.
-                    self_ty: if self_ty.has_concrete_skeleton() { Some(self_ty) } else { None },
+                    self_ty: self_ty.has_concrete_skeleton().then(|| self_ty),
                     intercrate_ambiguity_causes: overlap.intercrate_ambiguity_causes,
                     involves_placeholder: overlap.involves_placeholder,
                 }

compiler/rustc_ty_utils/src/abi.rs

@@ -207,11 +207,8 @@ fn fn_abi_of_instance<'tcx>(
 
     let sig = fn_sig_for_fn_abi(tcx, instance, param_env);
 
-    let caller_location = if instance.def.requires_caller_location(tcx) {
+    let caller_location =
-        Some(tcx.caller_location_ty())
+        instance.def.requires_caller_location(tcx).then(|| tcx.caller_location_ty());
-    } else {
-        None
-    };
 
     fn_abi_new_uncached(
         &LayoutCx { tcx, param_env },