Simplify some nested if statements

compiler/rustc_ast_lowering/src/index.rs

@@ -78,8 +78,7 @@ impl<'a, 'hir> NodeCollector<'a, 'hir> {
 
         // Make sure that the DepNode of some node coincides with the HirId
         // owner of that node.
-        if cfg!(debug_assertions) {
+        if cfg!(debug_assertions) && hir_id.owner != self.owner {
-            if hir_id.owner != self.owner {
             span_bug!(
                 span,
                 "inconsistent HirId at `{:?}` for `{:?}`: \
@@ -98,7 +97,6 @@ impl<'a, 'hir> NodeCollector<'a, 'hir> {
                 hir_id.owner,
             )
         }
-        }
 
         self.nodes[hir_id.local_id] = ParentedNode { parent: self.parent_node, node };
     }

compiler/rustc_ast_passes/src/ast_validation.rs

@@ -447,15 +447,15 @@ impl<'a> AstValidator<'a> {
     fn check_item_safety(&self, span: Span, safety: Safety) {
         match self.extern_mod_safety {
             Some(extern_safety) => {
-                if matches!(safety, Safety::Unsafe(_) | Safety::Safe(_)) {
+                if matches!(safety, Safety::Unsafe(_) | Safety::Safe(_))
-                    if extern_safety == Safety::Default {
+                    && extern_safety == Safety::Default
+                {
                     self.dcx().emit_err(errors::InvalidSafetyOnExtern {
                         item_span: span,
                         block: Some(self.current_extern_span().shrink_to_lo()),
                     });
                 }
             }
-            }
             None => {
                 if matches!(safety, Safety::Safe(_)) {
                     self.dcx().emit_err(errors::InvalidSafetyOnItem { span });

compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs

@@ -2574,8 +2574,8 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
         }
         impl<'hir> Visitor<'hir> for ExpressionFinder<'hir> {
             fn visit_expr(&mut self, e: &'hir hir::Expr<'hir>) {
-                if e.span.contains(self.capture_span) {
+                if e.span.contains(self.capture_span)
-                    if let hir::ExprKind::Closure(&hir::Closure {
+                    && let hir::ExprKind::Closure(&hir::Closure {
                         kind: hir::ClosureKind::Closure,
                         body,
                         fn_arg_span,
@@ -2593,15 +2593,13 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
                     self.visit_expr(body);
                     self.in_closure = false;
                 }
-                }
+                if let hir::Expr { kind: hir::ExprKind::Path(path), .. } = e
-                if let hir::Expr { kind: hir::ExprKind::Path(path), .. } = e {
+                    && let hir::QPath::Resolved(_, hir::Path { segments: [seg], .. }) = path
-                    if let hir::QPath::Resolved(_, hir::Path { segments: [seg], .. }) = path
                     && seg.ident.name == kw::SelfLower
                     && self.in_closure
                 {
                     self.closure_change_spans.push(e.span);
                 }
-                }
                 hir::intravisit::walk_expr(self, e);
             }
 
@@ -2609,8 +2607,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
                 if let hir::Pat { kind: hir::PatKind::Binding(_, hir_id, _ident, _), .. } =
                     local.pat
                     && let Some(init) = local.init
-                {
+                    && let hir::Expr {
-                    if let hir::Expr {
                         kind:
                             hir::ExprKind::Closure(&hir::Closure {
                                 kind: hir::ClosureKind::Closure,
@@ -2622,7 +2619,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
                 {
                     self.closure_local_id = Some(*hir_id);
                 }
-                }
+
                 hir::intravisit::walk_local(self, local);
             }
 

compiler/rustc_borrowck/src/lib.rs

@@ -2069,13 +2069,13 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, '_, 'tcx> {
                 // no move out from an earlier location) then this is an attempt at initialization
                 // of the union - we should error in that case.
                 let tcx = this.infcx.tcx;
-                if base.ty(this.body(), tcx).ty.is_union() {
+                if base.ty(this.body(), tcx).ty.is_union()
-                    if this.move_data.path_map[mpi].iter().any(|moi| {
+                    && this.move_data.path_map[mpi].iter().any(|moi| {
                         this.move_data.moves[*moi].source.is_predecessor_of(location, this.body)
-                    }) {
+                    })
+                {
                     return;
                 }
-                }
 
                 this.report_use_of_moved_or_uninitialized(
                     location,

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

@@ -353,13 +353,13 @@ impl<'a, 'typeck, 'b, 'tcx> LivenessResults<'a, 'typeck, 'b, 'tcx> {
             let location = self.cx.elements.to_location(drop_point);
             debug_assert_eq!(self.cx.body.terminator_loc(location.block), location,);
 
-            if self.cx.initialized_at_terminator(location.block, mpi) {
+            if self.cx.initialized_at_terminator(location.block, mpi)
-                if self.drop_live_at.insert(drop_point) {
+                && self.drop_live_at.insert(drop_point)
+            {
                 self.drop_locations.push(location);
                 self.stack.push(drop_point);
             }
         }
-        }
 
         debug!("compute_drop_live_points_for: drop_locations={:?}", self.drop_locations);
 

compiler/rustc_codegen_llvm/src/back/lto.rs

@@ -92,13 +92,11 @@ fn prepare_lto(
                     dcx.emit_err(LtoDylib);
                     return Err(FatalError);
                 }
-            } else if *crate_type == CrateType::ProcMacro {
+            } else if *crate_type == CrateType::ProcMacro && !cgcx.opts.unstable_opts.dylib_lto {
-                if !cgcx.opts.unstable_opts.dylib_lto {
                 dcx.emit_err(LtoProcMacro);
                 return Err(FatalError);
             }
         }
-        }
 
         if cgcx.opts.cg.prefer_dynamic && !cgcx.opts.unstable_opts.dylib_lto {
             dcx.emit_err(DynamicLinkingWithLTO);

compiler/rustc_codegen_ssa/src/codegen_attrs.rs

@@ -617,8 +617,8 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs {
     // purpose functions as they wouldn't have the right target features
     // enabled. For that reason we also forbid #[inline(always)] as it can't be
     // respected.
-    if !codegen_fn_attrs.target_features.is_empty() {
+    if !codegen_fn_attrs.target_features.is_empty() && codegen_fn_attrs.inline == InlineAttr::Always
-        if codegen_fn_attrs.inline == InlineAttr::Always {
+    {
         if let Some(span) = inline_span {
             tcx.dcx().span_err(
                 span,
@@ -627,10 +627,8 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs {
             );
         }
     }
-    }
 
-    if !codegen_fn_attrs.no_sanitize.is_empty() {
+    if !codegen_fn_attrs.no_sanitize.is_empty() && codegen_fn_attrs.inline == InlineAttr::Always {
-        if codegen_fn_attrs.inline == InlineAttr::Always {
         if let (Some(no_sanitize_span), Some(inline_span)) = (no_sanitize_span, inline_span) {
             let hir_id = tcx.local_def_id_to_hir_id(did);
             tcx.node_span_lint(
@@ -644,7 +642,6 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs {
             )
         }
     }
-    }
 
     if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::NAKED) {
         codegen_fn_attrs.inline = InlineAttr::Never;

compiler/rustc_const_eval/src/interpret/eval_context.rs

@@ -16,7 +16,7 @@ use rustc_span::Span;
 use rustc_target::abi::call::FnAbi;
 use rustc_target::abi::{Align, HasDataLayout, Size, TargetDataLayout};
 use rustc_trait_selection::traits::ObligationCtxt;
-use tracing::{debug, trace};
+use tracing::{debug, instrument, trace};
 
 use super::{
     err_inval, throw_inval, throw_ub, throw_ub_custom, Frame, FrameInfo, GlobalId, InterpErrorInfo,
@@ -315,6 +315,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
 
     /// Check if the two things are equal in the current param_env, using an infctx to get proper
     /// equality checks.
+    #[instrument(level = "trace", skip(self), ret)]
     pub(super) fn eq_in_param_env<T>(&self, a: T, b: T) -> bool
     where
         T: PartialEq + TypeFoldable<TyCtxt<'tcx>> + ToTrace<'tcx>,
@@ -330,15 +331,22 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
         // equate the two trait refs after normalization
         let a = ocx.normalize(&cause, self.param_env, a);
         let b = ocx.normalize(&cause, self.param_env, b);
-        if ocx.eq(&cause, self.param_env, a, b).is_ok() {
+
-            if ocx.select_all_or_error().is_empty() {
+        if let Err(terr) = ocx.eq(&cause, self.param_env, a, b) {
-                // All good.
+            trace!(?terr);
-                return true;
-            }
-        }
             return false;
         }
 
+        let errors = ocx.select_all_or_error();
+        if !errors.is_empty() {
+            trace!(?errors);
+            return false;
+        }
+
+        // All good.
+        true
+    }
+
     /// Walks up the callstack from the intrinsic's callsite, searching for the first callsite in a
     /// frame which is not `#[track_caller]`. This matches the `caller_location` intrinsic,
     /// and is primarily intended for the panic machinery.

compiler/rustc_driver_impl/src/pretty.rs

@@ -222,11 +222,9 @@ impl<'tcx> PrintExtra<'tcx> {
 }
 
 pub fn print<'tcx>(sess: &Session, ppm: PpMode, ex: PrintExtra<'tcx>) {
-    if ppm.needs_analysis() {
+    if ppm.needs_analysis() && ex.tcx().analysis(()).is_err() {
-        if ex.tcx().analysis(()).is_err() {
         FatalError.raise();
     }
-    }
 
     let (src, src_name) = get_source(sess);
 

compiler/rustc_hir_analysis/src/check/mod.rs

@@ -186,8 +186,7 @@ fn maybe_check_static_with_link_section(tcx: TyCtxt<'_>, id: LocalDefId) {
 
     if let Ok(alloc) = tcx.eval_static_initializer(id.to_def_id())
         && alloc.inner().provenance().ptrs().len() != 0
-    {
+        && attrs
-        if attrs
             .link_section
             .map(|link_section| !link_section.as_str().starts_with(".init_array"))
             .unwrap()
@@ -198,7 +197,6 @@ fn maybe_check_static_with_link_section(tcx: TyCtxt<'_>, id: LocalDefId) {
         tcx.dcx().span_err(tcx.def_span(id), msg);
     }
 }
-}
 
 fn report_forbidden_specialization(tcx: TyCtxt<'_>, impl_item: DefId, parent_impl: DefId) {
     let span = tcx.def_span(impl_item);

compiler/rustc_hir_analysis/src/coherence/mod.rs

@@ -53,8 +53,7 @@ fn enforce_trait_manually_implementable(
 ) -> Result<(), ErrorGuaranteed> {
     let impl_header_span = tcx.def_span(impl_def_id);
 
-    if tcx.is_lang_item(trait_def_id, LangItem::Freeze) {
+    if tcx.is_lang_item(trait_def_id, LangItem::Freeze) && !tcx.features().freeze_impls {
-        if !tcx.features().freeze_impls {
         feature_err(
             &tcx.sess,
             sym::freeze_impls,
@@ -64,7 +63,6 @@ fn enforce_trait_manually_implementable(
         .with_span_label(impl_header_span, format!("impl of `Freeze` not allowed"))
         .emit();
     }
-    }
 
     // Disallow *all* explicit impls of traits marked `#[rustc_deny_explicit_impl]`
     if trait_def.deny_explicit_impl {

compiler/rustc_hir_analysis/src/errors/wrong_number_of_generic_args.rs

@@ -827,8 +827,7 @@ impl<'a, 'tcx> WrongNumberOfGenericArgs<'a, 'tcx> {
 
             if num_generic_args_supplied_to_trait + num_assoc_fn_excess_args
                 == num_trait_generics_except_self
-            {
+                && let Some(span) = self.gen_args.span_ext()
-                if let Some(span) = self.gen_args.span_ext()
                 && let Ok(snippet) = self.tcx.sess.source_map().span_to_snippet(span)
             {
                 let sugg = vec![
@@ -843,7 +842,6 @@ impl<'a, 'tcx> WrongNumberOfGenericArgs<'a, 'tcx> {
             }
         }
     }
-    }
 
     fn suggest_moving_args_from_assoc_fn_to_trait_for_method_call(
         &self,

compiler/rustc_hir_typeck/src/cast.rs

@@ -732,13 +732,12 @@ impl<'a, 'tcx> CastCheck<'tcx> {
             }
             _ => return Err(CastError::NonScalar),
         };
-        if let ty::Adt(adt_def, _) = *self.expr_ty.kind() {
+        if let ty::Adt(adt_def, _) = *self.expr_ty.kind()
-            if adt_def.did().krate != LOCAL_CRATE {
+            && adt_def.did().krate != LOCAL_CRATE
-                if adt_def.variants().iter().any(VariantDef::is_field_list_non_exhaustive) {
+            && adt_def.variants().iter().any(VariantDef::is_field_list_non_exhaustive)
+        {
             return Err(CastError::ForeignNonExhaustiveAdt);
         }
-            }
-        }
         match (t_from, t_cast) {
             // These types have invariants! can't cast into them.
             (_, Int(CEnum) | FnPtr) => Err(CastError::NonScalar),

compiler/rustc_hir_typeck/src/expr.rs

@@ -1780,8 +1780,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
 
         // Make sure the programmer specified correct number of fields.
-        if adt_kind == AdtKind::Union {
+        if adt_kind == AdtKind::Union && hir_fields.len() != 1 {
-            if hir_fields.len() != 1 {
             struct_span_code_err!(
                 self.dcx(),
                 span,
@@ -1790,7 +1789,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             )
             .emit();
         }
-        }
 
         // If check_expr_struct_fields hit an error, do not attempt to populate
         // the fields with the base_expr. This could cause us to hit errors later

compiler/rustc_hir_typeck/src/method/suggest.rs

@@ -1252,12 +1252,12 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                             && suggested_bounds.contains(parent)
                         {
                             // We don't suggest `PartialEq` when we already suggest `Eq`.
-                        } else if !suggested_bounds.contains(pred) {
+                        } else if !suggested_bounds.contains(pred)
-                            if collect_type_param_suggestions(self_ty, *pred, &p) {
+                            && collect_type_param_suggestions(self_ty, *pred, &p)
+                        {
                             suggested = true;
                             suggested_bounds.insert(pred);
                         }
-                        }
                         (
                             match parent_pred {
                                 None => format!("`{p}`"),
@@ -1267,15 +1267,14 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                                         if !suggested
                                             && !suggested_bounds.contains(pred)
                                             && !suggested_bounds.contains(parent_pred)
-                                        {
+                                            && collect_type_param_suggestions(
-                                            if collect_type_param_suggestions(
                                                 self_ty,
                                                 *parent_pred,
                                                 &p,
-                                            ) {
+                                            )
+                                        {
                                             suggested_bounds.insert(pred);
                                         }
-                                        }
                                         format!("`{p}`\nwhich is required by `{parent_p}`")
                                     }
                                 },

compiler/rustc_lint/src/builtin.rs

@@ -429,11 +429,9 @@ impl MissingDoc {
         // Only check publicly-visible items, using the result from the privacy pass.
         // It's an option so the crate root can also use this function (it doesn't
         // have a `NodeId`).
-        if def_id != CRATE_DEF_ID {
+        if def_id != CRATE_DEF_ID && !cx.effective_visibilities.is_exported(def_id) {
-            if !cx.effective_visibilities.is_exported(def_id) {
             return;
         }
-        }
 
         let attrs = cx.tcx.hir().attrs(cx.tcx.local_def_id_to_hir_id(def_id));
         let has_doc = attrs.iter().any(has_doc);

compiler/rustc_middle/src/middle/stability.rs

@@ -444,11 +444,12 @@ impl<'tcx> TyCtxt<'tcx> {
                 // the `-Z force-unstable-if-unmarked` flag present (we're
                 // compiling a compiler crate), then let this missing feature
                 // annotation slide.
-                if feature == sym::rustc_private && issue == NonZero::new(27812) {
+                if feature == sym::rustc_private
-                    if self.sess.opts.unstable_opts.force_unstable_if_unmarked {
+                    && issue == NonZero::new(27812)
+                    && self.sess.opts.unstable_opts.force_unstable_if_unmarked
+                {
                     return EvalResult::Allow;
                 }
-                }
 
                 if matches!(allow_unstable, AllowUnstable::Yes) {
                     return EvalResult::Allow;

compiler/rustc_middle/src/mir/interpret/allocation.rs

@@ -448,8 +448,7 @@ impl<Prov: Provenance, Extra, Bytes: AllocBytes> Allocation<Prov, Extra, Bytes>
                 bad: uninit_range,
             }))
         })?;
-        if !Prov::OFFSET_IS_ADDR {
+        if !Prov::OFFSET_IS_ADDR && !self.provenance.range_empty(range, cx) {
-            if !self.provenance.range_empty(range, cx) {
             // Find the provenance.
             let (offset, _prov) = self
                 .provenance
@@ -464,7 +463,6 @@ impl<Prov: Provenance, Extra, Bytes: AllocBytes> Allocation<Prov, Extra, Bytes>
                 bad: AllocRange::from(start..end),
             })));
         }
-        }
         Ok(self.get_bytes_unchecked(range))
     }
 

compiler/rustc_middle/src/ty/context.rs

@@ -2606,8 +2606,7 @@ impl<'tcx> TyCtxt<'tcx> {
     /// With `cfg(debug_assertions)`, assert that args are compatible with their generics,
     /// and print out the args if not.
     pub fn debug_assert_args_compatible(self, def_id: DefId, args: &'tcx [ty::GenericArg<'tcx>]) {
-        if cfg!(debug_assertions) {
+        if cfg!(debug_assertions) && !self.check_args_compatible(def_id, args) {
-            if !self.check_args_compatible(def_id, args) {
             if let DefKind::AssocTy = self.def_kind(def_id)
                 && let DefKind::Impl { of_trait: false } = self.def_kind(self.parent(def_id))
             {
@@ -2635,7 +2634,6 @@ impl<'tcx> TyCtxt<'tcx> {
             }
         }
     }
-    }
 
     #[inline(always)]
     pub(crate) fn check_and_mk_args(

compiler/rustc_middle/src/ty/layout.rs

@@ -1183,12 +1183,12 @@ pub fn fn_can_unwind(tcx: TyCtxt<'_>, fn_def_id: Option<DefId>, abi: SpecAbi) ->
         //
         // This is not part of `codegen_fn_attrs` as it can differ between crates
         // and therefore cannot be computed in core.
-        if tcx.sess.opts.unstable_opts.panic_in_drop == PanicStrategy::Abort {
+        if tcx.sess.opts.unstable_opts.panic_in_drop == PanicStrategy::Abort
-            if tcx.is_lang_item(did, LangItem::DropInPlace) {
+            && tcx.is_lang_item(did, LangItem::DropInPlace)
+        {
             return false;
         }
     }
-    }
 
     // Otherwise if this isn't special then unwinding is generally determined by
     // the ABI of the itself. ABIs like `C` have variants which also

compiler/rustc_middle/src/ty/print/pretty.rs

@@ -3361,12 +3361,10 @@ pub fn trimmed_def_paths(tcx: TyCtxt<'_>, (): ()) -> DefIdMap<Symbol> {
                     // name.
                     //
                     // Any stable ordering would be fine here though.
-                    if *v.get() != symbol {
+                    if *v.get() != symbol && v.get().as_str() > symbol.as_str() {
-                        if v.get().as_str() > symbol.as_str() {
                         v.insert(symbol);
                     }
                 }
-                }
                 Vacant(v) => {
                     v.insert(symbol);
                 }

compiler/rustc_mir_build/src/build/coverageinfo/mcdc.rs

@@ -268,10 +268,9 @@ impl Builder<'_, '_> {
     pub(crate) fn mcdc_decrement_depth_if_enabled(&mut self) {
         if let Some(coverage_info) = self.coverage_info.as_mut()
             && let Some(mcdc_info) = coverage_info.mcdc_info.as_mut()
+            && mcdc_info.state.decision_ctx_stack.pop().is_none()
         {
-            if mcdc_info.state.decision_ctx_stack.pop().is_none() {
             bug!("Unexpected empty decision stack");
-            }
         };
     }
 }

compiler/rustc_mir_transform/src/check_const_item_mutation.rs

@@ -95,8 +95,8 @@ impl<'tcx> Visitor<'tcx> for ConstMutationChecker<'_, 'tcx> {
             // Check for assignment to fields of a constant
             // Assigning directly to a constant (e.g. `FOO = true;`) is a hard error,
             // so emitting a lint would be redundant.
-            if !lhs.projection.is_empty() {
+            if !lhs.projection.is_empty()
-                if let Some(def_id) = self.is_const_item_without_destructor(lhs.local)
+                && let Some(def_id) = self.is_const_item_without_destructor(lhs.local)
                 && let Some((lint_root, span, item)) =
                     self.should_lint_const_item_usage(lhs, def_id, loc)
             {
@@ -107,7 +107,7 @@ impl<'tcx> Visitor<'tcx> for ConstMutationChecker<'_, 'tcx> {
                     errors::ConstMutate::Modify { konst: item },
                 );
             }
-            }
+
             // We are looking for MIR of the form:
             //
             // ```

compiler/rustc_mir_transform/src/deduce_param_attrs.rs

@@ -168,8 +168,8 @@ pub(super) fn deduced_param_attrs<'tcx>(
     // Codegen won't use this information for anything if all the function parameters are passed
     // directly. Detect that and bail, for compilation speed.
     let fn_ty = tcx.type_of(def_id).instantiate_identity();
-    if matches!(fn_ty.kind(), ty::FnDef(..)) {
+    if matches!(fn_ty.kind(), ty::FnDef(..))
-        if fn_ty
+        && fn_ty
             .fn_sig(tcx)
             .inputs()
             .skip_binder()
@@ -179,7 +179,6 @@ pub(super) fn deduced_param_attrs<'tcx>(
     {
         return &[];
     }
-    }
 
     // Don't deduce any attributes for functions that have no MIR.
     if !tcx.is_mir_available(def_id) {

compiler/rustc_mir_transform/src/known_panics_lint.rs

@@ -378,11 +378,11 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
         if let (Some(l), Some(r)) = (l, r)
             && l.layout.ty.is_integral()
             && op.is_overflowing()
-        {
+            && self.use_ecx(|this| {
-            if self.use_ecx(|this| {
                 let (_res, overflow) = this.ecx.binary_op(op, &l, &r)?.to_scalar_pair();
                 overflow.to_bool()
-            })? {
+            })?
+        {
             self.report_assert_as_lint(
                 location,
                 AssertLintKind::ArithmeticOverflow,
@@ -390,7 +390,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
             );
             return None;
         }
-        }
+
         Some(())
     }
 

compiler/rustc_monomorphize/src/partitioning.rs

@@ -504,12 +504,10 @@ fn compute_inlined_overlap<'tcx>(cgu1: &CodegenUnit<'tcx>, cgu2: &CodegenUnit<'t
 
     let mut overlap = 0;
     for (item, data) in src_cgu.items().iter() {
-        if data.inlined {
+        if data.inlined && dst_cgu.items().contains_key(item) {
-            if dst_cgu.items().contains_key(item) {
             overlap += data.size_estimate;
         }
     }
-    }
     overlap
 }
 

compiler/rustc_next_trait_solver/src/canonicalizer.rs

@@ -185,14 +185,12 @@ impl<'a, D: SolverDelegate<Interner = I>, I: Interner> Canonicalizer<'a, D, I> {
                 for var in var_infos.iter_mut() {
                     // We simply put all regions from the input into the highest
                     // compressed universe, so we only deal with them at the end.
-                    if !var.is_region() {
+                    if !var.is_region() && is_existential == var.is_existential() {
-                        if is_existential == var.is_existential() {
                         update_uv(var, orig_uv, is_existential)
                     }
                 }
             }
         }
-        }
 
         // We uniquify regions and always put them into their own universe
         let mut first_region = true;

compiler/rustc_parse/src/parser/path.rs

@@ -671,13 +671,13 @@ impl<'a> Parser<'a> {
                     err.emit();
                     continue;
                 }
-                if !self.token.kind.should_end_const_arg() {
+                if !self.token.kind.should_end_const_arg()
-                    if self.handle_ambiguous_unbraced_const_arg(&mut args)? {
+                    && self.handle_ambiguous_unbraced_const_arg(&mut args)?
+                {
                     // We've managed to (partially) recover, so continue trying to parse
                     // arguments.
                     continue;
                 }
-                }
                 break;
             }
         }

compiler/rustc_passes/src/stability.rs

@@ -174,17 +174,15 @@ impl<'a, 'tcx> Annotator<'a, 'tcx> {
 
         // If the current node is a function, has const stability attributes and if it doesn not have an intrinsic ABI,
         // check if the function/method is const or the parent impl block is const
-        if let (Some(const_span), Some(fn_sig)) = (const_span, fn_sig) {
+        if let (Some(const_span), Some(fn_sig)) = (const_span, fn_sig)
-            if fn_sig.header.abi != Abi::RustIntrinsic && !fn_sig.header.is_const() {
+            && fn_sig.header.abi != Abi::RustIntrinsic
-                if !self.in_trait_impl
+            && !fn_sig.header.is_const()
-                    || (self.in_trait_impl && !self.tcx.is_const_fn_raw(def_id.to_def_id()))
+            && (!self.in_trait_impl || !self.tcx.is_const_fn_raw(def_id.to_def_id()))
         {
             self.tcx
                 .dcx()
                 .emit_err(errors::MissingConstErr { fn_sig_span: fn_sig.span, const_span });
         }
-            }
-        }
 
         // `impl const Trait for Type` items forward their const stability to their
         // immediate children.

compiler/rustc_resolve/src/diagnostics.rs

@@ -1233,8 +1233,8 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
                     && ns == namespace
                     && in_module != parent_scope.module
                     && !ident.span.normalize_to_macros_2_0().from_expansion()
+                    && filter_fn(res)
                 {
-                    if filter_fn(res) {
                     // create the path
                     let mut segms = if lookup_ident.span.at_least_rust_2018() {
                         // crate-local absolute paths start with `crate::` in edition 2018
@@ -1292,7 +1292,6 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
                         });
                     }
                 }
-                }
 
                 // collect submodules to explore
                 if let Some(module) = name_binding.module() {

compiler/rustc_resolve/src/ident.rs

@@ -958,13 +958,13 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
                 });
             }
 
-            if !restricted_shadowing && binding.expansion != LocalExpnId::ROOT {
+            if !restricted_shadowing
-                if let NameBindingKind::Import { import, .. } = binding.kind
+                && binding.expansion != LocalExpnId::ROOT
+                && let NameBindingKind::Import { import, .. } = binding.kind
                 && matches!(import.kind, ImportKind::MacroExport)
             {
                 self.macro_expanded_macro_export_errors.insert((path_span, binding.span));
             }
-            }
 
             self.record_use(ident, binding, used);
             return Ok(binding);

compiler/rustc_resolve/src/late.rs

@@ -4781,8 +4781,7 @@ impl<'a: 'ast, 'b, 'ast, 'tcx> LateResolutionVisitor<'a, 'b, 'ast, 'tcx> {
                 if let Some(res) = res
                     && let Some(def_id) = res.opt_def_id()
                     && !def_id.is_local()
-                {
+                    && self.r.tcx.crate_types().contains(&CrateType::ProcMacro)
-                    if self.r.tcx.crate_types().contains(&CrateType::ProcMacro)
                     && matches!(
                         self.r.tcx.sess.opts.resolve_doc_links,
                         ResolveDocLinks::ExportedMetadata
@@ -4791,7 +4790,6 @@ impl<'a: 'ast, 'b, 'ast, 'tcx> LateResolutionVisitor<'a, 'b, 'ast, 'tcx> {
                     // Encoding foreign def ids in proc macro crate metadata will ICE.
                     return None;
                 }
-                }
                 res
             });
         self.r.doc_link_resolutions = doc_link_resolutions;

compiler/rustc_resolve/src/late/diagnostics.rs

@@ -2255,8 +2255,8 @@ impl<'a: 'ast, 'ast, 'tcx> LateResolutionVisitor<'a, '_, 'ast, 'tcx> {
     fn let_binding_suggestion(&mut self, err: &mut Diag<'_>, ident_span: Span) -> bool {
         if let Some(Expr { kind: ExprKind::Assign(lhs, ..), .. }) = self.diag_metadata.in_assignment
             && let ast::ExprKind::Path(None, ref path) = lhs.kind
+            && !ident_span.from_expansion()
         {
-            if !ident_span.from_expansion() {
             let (span, text) = match path.segments.first() {
                 Some(seg) if let Some(name) = seg.ident.as_str().strip_prefix("let") => {
                     // a special case for #117894
@@ -2274,7 +2274,6 @@ impl<'a: 'ast, 'ast, 'tcx> LateResolutionVisitor<'a, '_, 'ast, 'tcx> {
             );
             return true;
         }
-        }
         false
     }
 

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

@@ -513,12 +513,11 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         // then there's nothing else to check.
         if let Some(closure_kind) = self_ty.to_opt_closure_kind()
             && let Some(goal_kind) = target_kind_ty.to_opt_closure_kind()
+            && closure_kind.extends(goal_kind)
         {
-            if closure_kind.extends(goal_kind) {
             candidates.vec.push(AsyncFnKindHelperCandidate);
         }
     }
-    }
 
     /// Implements one of the `Fn()` family for a fn pointer.
     fn assemble_fn_pointer_candidates(

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

@@ -1334,8 +1334,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             return;
         }
 
-        if self.can_use_global_caches(param_env) {
+        if self.can_use_global_caches(param_env) && !trait_pred.has_infer() {
-            if !trait_pred.has_infer() {
             debug!(?trait_pred, ?result, "insert_evaluation_cache global");
             // This may overwrite the cache with the same value
             // FIXME: Due to #50507 this overwrites the different values
@@ -1344,7 +1343,6 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             self.tcx().evaluation_cache.insert((param_env, trait_pred), dep_node, result);
             return;
         }
-        }
 
         debug!(?trait_pred, ?result, "insert_evaluation_cache");
         self.infcx.evaluation_cache.insert((param_env, trait_pred), dep_node, result);
@@ -1584,15 +1582,13 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         if self.can_use_global_caches(param_env) {
             if let Err(Overflow(OverflowError::Canonical)) = candidate {
                 // Don't cache overflow globally; we only produce this in certain modes.
-            } else if !pred.has_infer() {
+            } else if !pred.has_infer() && !candidate.has_infer() {
-                if !candidate.has_infer() {
                 debug!(?pred, ?candidate, "insert_candidate_cache global");
                 // This may overwrite the cache with the same value.
                 tcx.selection_cache.insert((param_env, pred), dep_node, candidate);
                 return;
             }
         }
-        }
 
         debug!(?pred, ?candidate, "insert_candidate_cache local");
         self.infcx.selection_cache.insert((param_env, pred), dep_node, candidate);
@@ -1980,11 +1976,11 @@ impl<'tcx> SelectionContext<'_, 'tcx> {
                 // impls have to be always applicable, meaning that the only allowed
                 // region constraints may be constraints also present on the default impl.
                 let tcx = self.tcx();
-                if other.evaluation.must_apply_modulo_regions() {
+                if other.evaluation.must_apply_modulo_regions()
-                    if tcx.specializes((other_def, victim_def)) {
+                    && tcx.specializes((other_def, victim_def))
+                {
                     return DropVictim::Yes;
                 }
-                }
 
                 match tcx.impls_are_allowed_to_overlap(other_def, victim_def) {
                     // For #33140 the impl headers must be exactly equal, the trait must not have

compiler/rustc_ty_utils/src/opaque_types.rs

@@ -143,13 +143,11 @@ impl<'tcx> OpaqueTypeCollector<'tcx> {
         match origin {
             rustc_hir::OpaqueTyOrigin::FnReturn(_) | rustc_hir::OpaqueTyOrigin::AsyncFn(_) => {}
             rustc_hir::OpaqueTyOrigin::TyAlias { in_assoc_ty, .. } => {
-                if !in_assoc_ty {
+                if !in_assoc_ty && !self.check_tait_defining_scope(alias_ty.def_id.expect_local()) {
-                    if !self.check_tait_defining_scope(alias_ty.def_id.expect_local()) {
                     return;
                 }
             }
         }
-        }
 
         self.opaques.push(alias_ty.def_id.expect_local());