Auto merge of #65632 - JohnTitor:rollup-adb16gb, r=JohnTitor

Rollup of 5 pull requests

Successful merges:

 - #65460 (Clean up `contains()` `insert()` chains on HashSet)
 - #65463 (Avoid unnecessary arena allocations in `expand_pattern()`.)
 - #65579 (Changed `resolve_type_vars_with_obligations` to also resolve const inference variables)
 - #65605 (Remove unreachable unit tuple compare binop codegen)
 - #65626 (trivial typo fix)

Failed merges:

r? @ghost

src/librustc/infer/resolve.rs

@@ -1,7 +1,7 @@
 use super::{InferCtxt, FixupError, FixupResult, Span};
 use super::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
 use crate::mir::interpret::ConstValue;
-use crate::ty::{self, Ty, Const, TyCtxt, TypeFoldable, InferConst, TypeFlags};
+use crate::ty::{self, Ty, Const, TyCtxt, TypeFoldable, InferConst};
 use crate::ty::fold::{TypeFolder, TypeVisitor};
 
 ///////////////////////////////////////////////////////////////////////////
@@ -29,7 +29,7 @@ impl<'a, 'tcx> TypeFolder<'tcx> for OpportunisticVarResolver<'a, 'tcx> {
     }
 
     fn fold_ty(&mut self, t: Ty<'tcx>) -> Ty<'tcx> {
-        if !t.has_infer_types() {
+        if !t.has_infer_types() && !t.has_infer_consts() {
             t // micro-optimize -- if there is nothing in this type that this fold affects...
         } else {
             let t = self.infcx.shallow_resolve(t);
@@ -38,7 +38,7 @@ impl<'a, 'tcx> TypeFolder<'tcx> for OpportunisticVarResolver<'a, 'tcx> {
     }
 
     fn fold_const(&mut self, ct: &'tcx Const<'tcx>) -> &'tcx Const<'tcx> {
-        if !ct.has_type_flags(TypeFlags::HAS_CT_INFER) {
+        if !ct.has_infer_consts() {
             ct // micro-optimize -- if there is nothing in this const that this fold affects...
         } else {
             let ct = self.infcx.shallow_resolve(ct);

src/librustc/middle/stability.rs

@@ -905,11 +905,10 @@ pub fn check_unused_or_stable_features(tcx: TyCtxt<'_>) {
             // Warn if the user has enabled an already-stable lang feature.
             unnecessary_stable_feature_lint(tcx, span, feature, since);
         }
-        if lang_features.contains(&feature) {
+        if !lang_features.insert(feature) {
             // Warn if the user enables a lang feature multiple times.
             duplicate_feature_err(tcx.sess, span, feature);
         }
-        lang_features.insert(feature);
     }
 
     let declared_lib_features = &tcx.features().declared_lib_features;

src/librustc/ty/fold.rs

@@ -88,6 +88,9 @@ pub trait TypeFoldable<'tcx>: fmt::Debug + Clone {
     fn has_infer_types(&self) -> bool {
         self.has_type_flags(TypeFlags::HAS_TY_INFER)
     }
+    fn has_infer_consts(&self) -> bool {
+        self.has_type_flags(TypeFlags::HAS_CT_INFER)
+    }
     fn has_local_value(&self) -> bool {
         self.has_type_flags(TypeFlags::KEEP_IN_LOCAL_TCX)
     }

src/librustc_codegen_llvm/debuginfo/metadata.rs

@@ -2069,11 +2069,9 @@ fn set_members_of_composite_type(cx: &CodegenCx<'ll, 'tcx>,
     {
         let mut composite_types_completed =
             debug_context(cx).composite_types_completed.borrow_mut();
-        if composite_types_completed.contains(&composite_type_metadata) {
+        if !composite_types_completed.insert(&composite_type_metadata) {
             bug!("debuginfo::set_members_of_composite_type() - \
                   Already completed forward declaration re-encountered.");
-        } else {
-            composite_types_completed.insert(composite_type_metadata);
         }
     }
 

src/librustc_codegen_ssa/mir/rvalue.rs

@@ -556,7 +556,6 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
     ) -> Bx::Value {
         let is_float = input_ty.is_floating_point();
         let is_signed = input_ty.is_signed();
-        let is_unit = input_ty.is_unit();
         match op {
             mir::BinOp::Add => if is_float {
                 bx.fadd(lhs, rhs)
@@ -594,13 +593,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             mir::BinOp::Shl => common::build_unchecked_lshift(bx, lhs, rhs),
             mir::BinOp::Shr => common::build_unchecked_rshift(bx, input_ty, lhs, rhs),
             mir::BinOp::Ne | mir::BinOp::Lt | mir::BinOp::Gt |
-            mir::BinOp::Eq | mir::BinOp::Le | mir::BinOp::Ge => if is_unit {
-                bx.cx().const_bool(match op {
-                    mir::BinOp::Ne | mir::BinOp::Lt | mir::BinOp::Gt => false,
-                    mir::BinOp::Eq | mir::BinOp::Le | mir::BinOp::Ge => true,
-                    _ => unreachable!()
-                })
-            } else if is_float {
+            mir::BinOp::Eq | mir::BinOp::Le | mir::BinOp::Ge => if is_float {
                 bx.fcmp(
                     base::bin_op_to_fcmp_predicate(op.to_hir_binop()),
                     lhs, rhs

src/librustc_metadata/native_libs.rs

@@ -198,12 +198,10 @@ impl Collector<'tcx> {
                     self.tcx.sess.err(&format!("renaming of the library `{}` was specified, \
                                                 however this crate contains no `#[link(...)]` \
                                                 attributes referencing this library.", name));
-                } else if renames.contains(name) {
+                } else if !renames.insert(name) {
                     self.tcx.sess.err(&format!("multiple renamings were \
                                                 specified for library `{}` .",
                                                name));
-                } else {
-                    renames.insert(name);
                 }
             }
         }

src/librustc_mir/borrow_check/conflict_errors.rs

@@ -78,16 +78,14 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                 .last()
                 .unwrap();
 
-            if self.uninitialized_error_reported.contains(&root_place) {
+            if !self.uninitialized_error_reported.insert(root_place) {
                 debug!(
                     "report_use_of_moved_or_uninitialized place: error about {:?} suppressed",
                     root_place
                 );
                 return;
             }
 
-            self.uninitialized_error_reported.insert(root_place);
-
             let item_msg = match self.describe_place_with_options(used_place,
                                                                   IncludingDowncast(true)) {
                 Some(name) => format!("`{}`", name),

src/librustc_mir/hair/pattern/_match.rs

@@ -189,8 +189,8 @@ use std::ops::RangeInclusive;
 use std::u128;
 use std::convert::TryInto;
 
-pub fn expand_pattern<'a, 'tcx>(cx: &MatchCheckCtxt<'a, 'tcx>, pat: Pat<'tcx>) -> &'a Pat<'tcx> {
-    cx.pattern_arena.alloc(LiteralExpander { tcx: cx.tcx }.fold_pattern(&pat))
+pub fn expand_pattern<'a, 'tcx>(cx: &MatchCheckCtxt<'a, 'tcx>, pat: Pat<'tcx>) -> Pat<'tcx> {
+    LiteralExpander { tcx: cx.tcx }.fold_pattern(&pat)
 }
 
 struct LiteralExpander<'tcx> {

src/librustc_mir/hair/pattern/check_match.rs

@@ -154,7 +154,8 @@ impl<'tcx> MatchVisitor<'_, 'tcx> {
                         self.tables
                     );
                     patcx.include_lint_checks();
-                    let pattern = expand_pattern(cx, patcx.lower_pattern(&pat));
+                    let pattern =
+                        cx.pattern_arena.alloc(expand_pattern(cx, patcx.lower_pattern(&pat))) as &_;
                     if !patcx.errors.is_empty() {
                         patcx.report_inlining_errors(pat.span);
                         have_errors = true;
@@ -253,8 +254,9 @@ impl<'tcx> MatchVisitor<'_, 'tcx> {
             patcx.include_lint_checks();
             let pattern = patcx.lower_pattern(pat);
             let pattern_ty = pattern.ty;
+            let pattern = expand_pattern(cx, pattern);
             let pats: Matrix<'_, '_> = vec![smallvec![
-                expand_pattern(cx, pattern)
+                &pattern
             ]].into_iter().collect();
 
             let witnesses = match check_not_useful(cx, pattern_ty, &pats, pat.hir_id) {

src/librustc_mir/hair/pattern/mod.rs

@@ -1214,7 +1214,7 @@ fn search_for_adt_without_structural_match<'tcx>(tcx: TyCtxt<'tcx>,
 
         // tracks ADT's previously encountered during search, so that
         // we will not recur on them again.
-        seen: FxHashSet<&'tcx AdtDef>,
+        seen: FxHashSet<hir::def_id::DefId>,
     }
 
     impl<'tcx> TypeVisitor<'tcx> for Search<'tcx> {
@@ -1254,14 +1254,12 @@ fn search_for_adt_without_structural_match<'tcx>(tcx: TyCtxt<'tcx>,
                 return true // Halt visiting!
             }
 
-            if self.seen.contains(adt_def) {
+            if !self.seen.insert(adt_def.did) {
                 debug!("Search already seen adt_def: {:?}", adt_def);
                 // let caller continue its search
                 return false;
             }
 
-            self.seen.insert(adt_def);
-
             // `#[structural_match]` does not care about the
             // instantiation of the generics in an ADT (it
             // instead looks directly at its fields outside

src/librustc_mir/lints.rs

@@ -72,13 +72,11 @@ fn check_fn_for_unconditional_recursion(
     let caller_substs = &InternalSubsts::identity_for_item(tcx, def_id)[..trait_substs_count];
 
     while let Some(bb) = reachable_without_self_call_queue.pop() {
-        if visited.contains(bb) {
+        if !visited.insert(bb) {
             //already done
             continue;
         }
 
-        visited.insert(bb);
-
         let block = &basic_blocks[bb];
 
         if let Some(ref terminator) = block.terminator {

src/librustc_resolve/resolve_imports.rs

@@ -673,13 +673,12 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
                     self.throw_unresolved_import_error(errors, None);
                     errors = vec![];
                 }
-                if !seen_spans.contains(&err.span) {
+                if seen_spans.insert(err.span) {
                     let path = import_path_to_string(
                         &import.module_path.iter().map(|seg| seg.ident).collect::<Vec<_>>(),
                         &import.subclass,
                         err.span,
                     );
-                    seen_spans.insert(err.span);
                     errors.push((path, err));
                     prev_root_id = import.root_id;
                 }

src/librustc_typeck/check/coercion.rs

@@ -811,7 +811,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         target: Ty<'tcx>,
         allow_two_phase: AllowTwoPhase,
     ) -> RelateResult<'tcx, Ty<'tcx>> {
-        let source = self.resolve_type_vars_with_obligations(expr_ty);
+        let source = self.resolve_vars_with_obligations(expr_ty);
         debug!("coercion::try({:?}: {:?} -> {:?})", expr, source, target);
 
         let cause = self.cause(expr.span, ObligationCauseCode::ExprAssignable);
@@ -829,7 +829,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
     /// Same as `try_coerce()`, but without side-effects.
     pub fn can_coerce(&self, expr_ty: Ty<'tcx>, target: Ty<'tcx>) -> bool {
-        let source = self.resolve_type_vars_with_obligations(expr_ty);
+        let source = self.resolve_vars_with_obligations(expr_ty);
         debug!("coercion::can({:?} -> {:?})", source, target);
 
         let cause = self.cause(syntax_pos::DUMMY_SP, ObligationCauseCode::ExprAssignable);
@@ -853,8 +853,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                                 -> RelateResult<'tcx, Ty<'tcx>>
         where E: AsCoercionSite
     {
-        let prev_ty = self.resolve_type_vars_with_obligations(prev_ty);
-        let new_ty = self.resolve_type_vars_with_obligations(new_ty);
+        let prev_ty = self.resolve_vars_with_obligations(prev_ty);
+        let new_ty = self.resolve_vars_with_obligations(new_ty);
         debug!("coercion::try_find_coercion_lub({:?}, {:?})", prev_ty, new_ty);
 
         // Special-case that coercion alone cannot handle:
@@ -1333,7 +1333,7 @@ impl<'tcx, 'exprs, E: AsCoercionSite> CoerceMany<'tcx, 'exprs, E> {
             err.span_label(return_sp, "expected because this return type...");
             err.span_label( *sp, format!(
                 "...is found to be `{}` here",
-                fcx.resolve_type_vars_with_obligations(expected),
+                fcx.resolve_vars_with_obligations(expected),
             ));
         }
         err

src/librustc_typeck/check/demand.rs

@@ -108,7 +108,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                               expected: Ty<'tcx>,
                               allow_two_phase: AllowTwoPhase)
                               -> (Ty<'tcx>, Option<DiagnosticBuilder<'tcx>>) {
-        let expected = self.resolve_type_vars_with_obligations(expected);
+        let expected = self.resolve_vars_with_obligations(expected);
 
         let e = match self.try_coerce(expr, checked_ty, expected, allow_two_phase) {
             Ok(ty) => return (ty, None),
@@ -117,7 +117,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
         let expr = expr.peel_drop_temps();
         let cause = self.misc(expr.span);
-        let expr_ty = self.resolve_type_vars_with_obligations(checked_ty);
+        let expr_ty = self.resolve_vars_with_obligations(checked_ty);
         let mut err = self.report_mismatched_types(&cause, expected, expr_ty, e);
 
         if self.is_assign_to_bool(expr, expected) {

src/librustc_typeck/check/expr.rs

@@ -1010,7 +1010,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         expr: &'tcx hir::Expr,
     ) -> Ty<'tcx> {
         let flds = expected.only_has_type(self).and_then(|ty| {
-            let ty = self.resolve_type_vars_with_obligations(ty);
+            let ty = self.resolve_vars_with_obligations(ty);
             match ty.kind {
                 ty::Tuple(ref flds) => Some(&flds[..]),
                 _ => None

src/librustc_typeck/check/method/suggest.rs

@@ -919,7 +919,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         // This occurs for UFCS desugaring of `T::method`, where there is no
         // receiver expression for the method call, and thus no autoderef.
         if let SelfSource::QPath(_) = source {
-            return is_local(self.resolve_type_vars_with_obligations(rcvr_ty));
+            return is_local(self.resolve_vars_with_obligations(rcvr_ty));
         }
 
         self.autoderef(span, rcvr_ty).any(|(ty, _)| is_local(ty))

src/librustc_typeck/check/mod.rs

@@ -2440,23 +2440,23 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         self.cause(span, ObligationCauseCode::MiscObligation)
     }
 
-    /// Resolves type variables in `ty` if possible. Unlike the infcx
+    /// Resolves type and const variables in `ty` if possible. Unlike the infcx
     /// version (resolve_vars_if_possible), this version will
     /// also select obligations if it seems useful, in an effort
     /// to get more type information.
-    fn resolve_type_vars_with_obligations(&self, mut ty: Ty<'tcx>) -> Ty<'tcx> {
-        debug!("resolve_type_vars_with_obligations(ty={:?})", ty);
+    fn resolve_vars_with_obligations(&self, mut ty: Ty<'tcx>) -> Ty<'tcx> {
+        debug!("resolve_vars_with_obligations(ty={:?})", ty);
 
         // No Infer()? Nothing needs doing.
-        if !ty.has_infer_types() {
-            debug!("resolve_type_vars_with_obligations: ty={:?}", ty);
+        if !ty.has_infer_types() && !ty.has_infer_consts() {
+            debug!("resolve_vars_with_obligations: ty={:?}", ty);
             return ty;
         }
 
         // If `ty` is a type variable, see whether we already know what it is.
         ty = self.resolve_vars_if_possible(&ty);
-        if !ty.has_infer_types() {
-            debug!("resolve_type_vars_with_obligations: ty={:?}", ty);
+        if !ty.has_infer_types() && !ty.has_infer_consts()  {
+            debug!("resolve_vars_with_obligations: ty={:?}", ty);
             return ty;
         }
 
@@ -2467,7 +2467,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         self.select_obligations_where_possible(false, |_| {});
         ty = self.resolve_vars_if_possible(&ty);
 
-        debug!("resolve_type_vars_with_obligations: ty={:?}", ty);
+        debug!("resolve_vars_with_obligations: ty={:?}", ty);
         ty
     }
 
@@ -3668,7 +3668,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                                            formal_ret: Ty<'tcx>,
                                            formal_args: &[Ty<'tcx>])
                                            -> Vec<Ty<'tcx>> {
-        let formal_ret = self.resolve_type_vars_with_obligations(formal_ret);
+        let formal_ret = self.resolve_vars_with_obligations(formal_ret);
         let ret_ty = match expected_ret.only_has_type(self) {
             Some(ret) => ret,
             None => return Vec::new()
@@ -4517,7 +4517,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 err.span_suggestion(
                     span,
                     "try adding a return type",
-                    format!("-> {} ", self.resolve_type_vars_with_obligations(found)),
+                    format!("-> {} ", self.resolve_vars_with_obligations(found)),
                     Applicability::MachineApplicable);
                 true
             }
@@ -4993,7 +4993,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     // If no resolution is possible, then an error is reported.
     // Numeric inference variables may be left unresolved.
     pub fn structurally_resolved_type(&self, sp: Span, ty: Ty<'tcx>) -> Ty<'tcx> {
-        let ty = self.resolve_type_vars_with_obligations(ty);
+        let ty = self.resolve_vars_with_obligations(ty);
         if !ty.is_ty_var() {
             ty
         } else {

src/librustc_typeck/check/op.rs

@@ -179,7 +179,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 self.check_expr_with_needs(lhs_expr, Needs::MutPlace)
             }
         };
-        let lhs_ty = self.resolve_type_vars_with_obligations(lhs_ty);
+        let lhs_ty = self.resolve_vars_with_obligations(lhs_ty);
 
         // N.B., as we have not yet type-checked the RHS, we don't have the
         // type at hand. Make a variable to represent it. The whole reason
@@ -196,7 +196,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
         // see `NB` above
         let rhs_ty = self.check_expr_coercable_to_type(rhs_expr, rhs_ty_var);
-        let rhs_ty = self.resolve_type_vars_with_obligations(rhs_ty);
+        let rhs_ty = self.resolve_vars_with_obligations(rhs_ty);
 
         let return_ty = match result {
             Ok(method) => {

src/librustc_typeck/check/pat.rs

@@ -251,7 +251,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         expected: Ty<'tcx>,
         mut def_bm: BindingMode,
     ) -> (Ty<'tcx>, BindingMode) {
-        let mut expected = self.resolve_type_vars_with_obligations(&expected);
+        let mut expected = self.resolve_vars_with_obligations(&expected);
 
         // Peel off as many `&` or `&mut` from the scrutinee type as possible. For example,
         // for `match &&&mut Some(5)` the loop runs three times, aborting when it reaches

src/libsyntax/lib.rs

@@ -67,7 +67,7 @@ pub struct Globals {
 impl Globals {
     fn new(edition: Edition) -> Globals {
         Globals {
-            // We have no idea how many attributes their will be, so just
+            // We have no idea how many attributes there will be, so just
             // initiate the vectors with 0 bits. We'll grow them as necessary.
             used_attrs: Lock::new(GrowableBitSet::new_empty()),
             known_attrs: Lock::new(GrowableBitSet::new_empty()),