Rename all mentions of nil to unit

src/librustc/traits/error_reporting.rs

@@ -661,7 +661,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
                         {
                             let predicate = trait_predicate.map_bound(|mut trait_pred| {
                                 trait_pred.trait_ref.substs = self.tcx.mk_substs_trait(
-                                    self.tcx.mk_nil(),
+                                    self.tcx.mk_unit(),
                                     &trait_pred.trait_ref.substs[1..],
                                 );
                                 trait_pred

src/librustc/ty/codec.rs

@@ -298,7 +298,7 @@ macro_rules! implement_ty_decoder {
                 type Error = String;
 
                 __impl_decoder_methods! {
-                    read_nil -> ();
+                    read_unit -> ();
 
                     read_u128 -> u128;
                     read_u64 -> u64;

src/librustc/ty/context.rs

@@ -2491,8 +2491,8 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         self.mk_ptr(TypeAndMut {ty: ty, mutbl: hir::MutImmutable})
     }
 
-    pub fn mk_nil_ptr(self) -> Ty<'tcx> {
-        self.mk_imm_ptr(self.mk_nil())
+    pub fn mk_unit_ptr(self) -> Ty<'tcx> {
+        self.mk_imm_ptr(self.mk_unit())
     }
 
     pub fn mk_array(self, ty: Ty<'tcx>, n: u64) -> Ty<'tcx> {
@@ -2511,7 +2511,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         iter.intern_with(|ts| self.mk_ty(Tuple(self.intern_type_list(ts))))
     }
 
-    pub fn mk_nil(self) -> Ty<'tcx> {
+    pub fn mk_unit(self) -> Ty<'tcx> {
         self.intern_tup(&[])
     }
 

src/librustc/ty/layout.rs

@@ -132,7 +132,7 @@ impl PrimitiveExt for Primitive {
             Int(i, signed) => i.to_ty(tcx, signed),
             Float(FloatTy::F32) => tcx.types.f32,
             Float(FloatTy::F64) => tcx.types.f64,
-            Pointer => tcx.mk_mut_ptr(tcx.mk_nil()),
+            Pointer => tcx.mk_mut_ptr(tcx.mk_unit()),
         }
     }
 }
@@ -1606,7 +1606,7 @@ impl<'a, 'tcx, C> TyLayoutMethods<'tcx, C> for Ty<'tcx>
                 // (which may have no non-DST form), and will work as long
                 // as the `Abi` or `FieldPlacement` is checked by users.
                 if i == 0 {
-                    let nil = tcx.mk_nil();
+                    let nil = tcx.mk_unit();
                     let ptr_ty = if this.ty.is_unsafe_ptr() {
                         tcx.mk_mut_ptr(nil)
                     } else {

src/librustc/ty/query/on_disk_cache.rs

@@ -1020,7 +1020,7 @@ impl<'enc, 'a, 'tcx, E> Encoder for CacheEncoder<'enc, 'a, 'tcx, E>
 {
     type Error = E::Error;
 
-    fn emit_nil(&mut self) -> Result<(), Self::Error> {
+    fn emit_unit(&mut self) -> Result<(), Self::Error> {
         Ok(())
     }
 

src/librustc/ty/sty.rs

@@ -1458,7 +1458,7 @@ impl RegionKind {
 
 /// Type utilities
 impl<'a, 'gcx, 'tcx> TyS<'tcx> {
-    pub fn is_nil(&self) -> bool {
+    pub fn is_unit(&self) -> bool {
         match self.sty {
             Tuple(ref tys) => tys.is_empty(),
             _ => false,

src/librustc/util/ppaux.rs

@@ -234,7 +234,7 @@ impl PrintContext {
             }
         }
         write!(f, ")")?;
-        if !output.is_nil() {
+        if !output.is_unit() {
             print!(f, self, write(" -> "), print_display(output))?;
         }
 

src/librustc_codegen_llvm/debuginfo/type_names.rs

@@ -160,7 +160,7 @@ pub fn push_debuginfo_type_name<'a, 'tcx>(cx: &CodegenCx<'a, 'tcx>,
 
             output.push(')');
 
-            if !sig.output().is_nil() {
+            if !sig.output().is_unit() {
                 output.push_str(" -> ");
                 push_debuginfo_type_name(cx, sig.output(), true, output);
             }

src/librustc_codegen_llvm/intrinsic.rs

@@ -968,7 +968,7 @@ fn get_rust_try_fn<'ll, 'tcx>(
     let i8p = tcx.mk_mut_ptr(tcx.types.i8);
     let fn_ty = tcx.mk_fn_ptr(ty::Binder::bind(tcx.mk_fn_sig(
         iter::once(i8p),
-        tcx.mk_nil(),
+        tcx.mk_unit(),
         false,
         hir::Unsafety::Unsafe,
         Abi::Rust

src/librustc_codegen_llvm/mir/rvalue.rs

@@ -566,7 +566,7 @@ impl FunctionCx<'a, 'll, 'tcx> {
     ) -> &'ll Value {
         let is_float = input_ty.is_fp();
         let is_signed = input_ty.is_signed();
-        let is_nil = input_ty.is_nil();
+        let is_unit = input_ty.is_unit();
         match op {
             mir::BinOp::Add => if is_float {
                 bx.fadd(lhs, rhs)
@@ -604,7 +604,7 @@ impl FunctionCx<'a, 'll, 'tcx> {
             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_nil {
+            mir::BinOp::Eq | mir::BinOp::Le | mir::BinOp::Ge => if is_unit {
                 C_bool(bx.cx, match op {
                     mir::BinOp::Ne | mir::BinOp::Lt | mir::BinOp::Gt => false,
                     mir::BinOp::Eq | mir::BinOp::Le | mir::BinOp::Ge => true,

src/librustc_driver/test.rs

@@ -308,8 +308,8 @@ impl<'a, 'gcx, 'tcx> Env<'a, 'gcx, 'tcx> {
         )))
     }
 
-    pub fn t_nil(&self) -> Ty<'tcx> {
-        self.infcx.tcx.mk_nil()
+    pub fn t_unit(&self) -> Ty<'tcx> {
+        self.infcx.tcx.mk_unit()
     }
 
     pub fn t_pair(&self, ty1: Ty<'tcx>, ty2: Ty<'tcx>) -> Ty<'tcx> {
@@ -491,7 +491,7 @@ fn subst_ty_renumber_bound() {
         // t_source = fn(A)
         let t_source = {
             let t_param = env.t_param(0);
-            env.t_fn(&[t_param], env.t_nil())
+            env.t_fn(&[t_param], env.t_unit())
         };
 
         let substs = env.infcx.tcx.intern_substs(&[t_rptr_bound1.into()]);
@@ -500,7 +500,7 @@ fn subst_ty_renumber_bound() {
         // t_expected = fn(&'a isize)
         let t_expected = {
             let t_ptr_bound2 = env.t_rptr_late_bound_with_debruijn(1, d2());
-            env.t_fn(&[t_ptr_bound2], env.t_nil())
+            env.t_fn(&[t_ptr_bound2], env.t_unit())
         };
 
         debug!("subst_bound: t_source={:?} substs={:?} t_substituted={:?} t_expected={:?}",
@@ -526,7 +526,7 @@ fn subst_ty_renumber_some_bounds() {
         // t_source = (A, fn(A))
         let t_source = {
             let t_param = env.t_param(0);
-            env.t_pair(t_param, env.t_fn(&[t_param], env.t_nil()))
+            env.t_pair(t_param, env.t_fn(&[t_param], env.t_unit()))
         };
 
         let substs = env.infcx.tcx.intern_substs(&[t_rptr_bound1.into()]);
@@ -537,7 +537,7 @@ fn subst_ty_renumber_some_bounds() {
         // but not that the Debruijn index is different in the different cases.
         let t_expected = {
             let t_rptr_bound2 = env.t_rptr_late_bound_with_debruijn(1, d2());
-            env.t_pair(t_rptr_bound1, env.t_fn(&[t_rptr_bound2], env.t_nil()))
+            env.t_pair(t_rptr_bound1, env.t_fn(&[t_rptr_bound2], env.t_unit()))
         };
 
         debug!("subst_bound: t_source={:?} substs={:?} t_substituted={:?} t_expected={:?}",
@@ -559,7 +559,7 @@ fn escaping() {
         // Theta = [A -> &'a foo]
         env.create_simple_region_hierarchy();
 
-        assert!(!env.t_nil().has_escaping_regions());
+        assert!(!env.t_unit().has_escaping_regions());
 
         let t_rptr_free1 = env.t_rptr_free(1);
         assert!(!t_rptr_free1.has_escaping_regions());
@@ -573,7 +573,7 @@ fn escaping() {
         // t_fn = fn(A)
         let t_param = env.t_param(0);
         assert!(!t_param.has_escaping_regions());
-        let t_fn = env.t_fn(&[t_param], env.t_nil());
+        let t_fn = env.t_fn(&[t_param], env.t_unit());
         assert!(!t_fn.has_escaping_regions());
     })
 }
@@ -588,7 +588,7 @@ fn subst_region_renumber_region() {
         // type t_source<'a> = fn(&'a isize)
         let t_source = {
             let re_early = env.re_early_bound(0, "'a");
-            env.t_fn(&[env.t_rptr(re_early)], env.t_nil())
+            env.t_fn(&[env.t_rptr(re_early)], env.t_unit())
         };
 
         let substs = env.infcx.tcx.intern_substs(&[re_bound1.into()]);
@@ -599,7 +599,7 @@ fn subst_region_renumber_region() {
         // but not that the Debruijn index is different in the different cases.
         let t_expected = {
             let t_rptr_bound2 = env.t_rptr_late_bound_with_debruijn(1, d2());
-            env.t_fn(&[t_rptr_bound2], env.t_nil())
+            env.t_fn(&[t_rptr_bound2], env.t_unit())
         };
 
         debug!("subst_bound: t_source={:?} substs={:?} t_substituted={:?} t_expected={:?}",

src/librustc_lint/types.rs

@@ -691,7 +691,7 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
                 }
 
                 let sig = cx.erase_late_bound_regions(&sig);
-                if !sig.output().is_nil() {
+                if !sig.output().is_unit() {
                     let r = self.check_type_for_ffi(cache, sig.output());
                     match r {
                         FfiSafe => {}
@@ -767,7 +767,7 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
 
         if let hir::Return(ref ret_hir) = decl.output {
             let ret_ty = sig.output();
-            if !ret_ty.is_nil() {
+            if !ret_ty.is_unit() {
                 self.check_type_for_ffi_and_report_errors(ret_hir.span, ret_ty);
             }
         }

src/librustc_metadata/encoder.rs

@@ -75,7 +75,7 @@ macro_rules! encoder_methods {
 impl<'a, 'tcx> Encoder for EncodeContext<'a, 'tcx> {
     type Error = <opaque::Encoder as Encoder>::Error;
 
-    fn emit_nil(&mut self) -> Result<(), Self::Error> {
+    fn emit_unit(&mut self) -> Result<(), Self::Error> {
         Ok(())
     }
 

src/librustc_mir/build/block.rs

@@ -177,7 +177,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
             // the case of `!`, no return value is required, as the block will never return.
             let tcx = this.hir.tcx();
             let ty = destination.ty(&this.local_decls, tcx).to_ty(tcx);
-            if ty.is_nil() {
+            if ty.is_unit() {
                 // We only want to assign an implicit `()` as the return value of the block if the
                 // block does not diverge. (Otherwise, we may try to assign a unit to a `!`-type.)
                 this.cfg.push_assign_unit(block, source_info, destination);

src/librustc_mir/hair/cx/mod.rs

@@ -118,7 +118,7 @@ impl<'a, 'gcx, 'tcx> Cx<'a, 'gcx, 'tcx> {
     }
 
     pub fn unit_ty(&mut self) -> Ty<'tcx> {
-        self.tcx.mk_nil()
+        self.tcx.mk_unit()
     }
 
     pub fn true_literal(&mut self) -> &'tcx ty::Const<'tcx> {

src/librustc_mir/interpret/terminator.rs

@@ -436,7 +436,7 @@ impl<'a, 'mir, 'tcx, M: Machine<'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M> {
             layout: self.layout_of(self.tcx.mk_mut_ptr(place.layout.ty))?,
         };
 
-        let ty = self.tcx.mk_nil(); // return type is ()
+        let ty = self.tcx.mk_unit(); // return type is ()
         let dest = PlaceTy::null(&self, self.layout_of(ty)?);
 
         self.eval_fn_call(

src/librustc_mir/monomorphize/item.rs

@@ -368,7 +368,7 @@ impl<'a, 'tcx> DefPathBasedNames<'a, 'tcx> {
 
                 output.push(')');
 
-                if !sig.output().is_nil() {
+                if !sig.output().is_unit() {
                     output.push_str(" -> ");
                     self.push_type_name(sig.output(), output);
                 }

src/librustc_mir/transform/generator.rs

@@ -517,7 +517,7 @@ fn compute_layout<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
     }
 
     let upvar_len = mir.upvar_decls.len();
-    let dummy_local = LocalDecl::new_internal(tcx.mk_nil(), mir.span);
+    let dummy_local = LocalDecl::new_internal(tcx.mk_unit(), mir.span);
 
     // Gather live locals and their indices replacing values in mir.local_decls with a dummy
     // to avoid changing local indices
@@ -655,7 +655,7 @@ fn create_generator_drop_shim<'a, 'tcx>(
     // Replace the return variable
     mir.local_decls[RETURN_PLACE] = LocalDecl {
         mutability: Mutability::Mut,
-        ty: tcx.mk_nil(),
+        ty: tcx.mk_unit(),
         name: None,
         source_info,
         visibility_scope: source_info.scope,

src/librustc_mir/util/elaborate_drops.rs

@@ -529,7 +529,7 @@ impl<'l, 'b, 'tcx, D> DropCtxt<'l, 'b, 'tcx, D>
             mutbl: hir::Mutability::MutMutable
         });
         let ref_place = self.new_temp(ref_ty);
-        let unit_temp = Place::Local(self.new_temp(tcx.mk_nil()));
+        let unit_temp = Place::Local(self.new_temp(tcx.mk_unit()));
 
         let result = BasicBlockData {
             statements: vec![self.assign(
@@ -891,7 +891,7 @@ impl<'l, 'b, 'tcx, D> DropCtxt<'l, 'b, 'tcx, D>
         unwind: Unwind
     ) -> BasicBlock {
         let tcx = self.tcx();
-        let unit_temp = Place::Local(self.new_temp(tcx.mk_nil()));
+        let unit_temp = Place::Local(self.new_temp(tcx.mk_unit()));
         let free_func = tcx.require_lang_item(lang_items::BoxFreeFnLangItem);
         let args = adt.variants[0].fields.iter().enumerate().map(|(i, f)| {
             let field = Field::new(i);

src/librustc_typeck/astconv.rs

@@ -1575,7 +1575,7 @@ impl<'o, 'gcx: 'tcx, 'tcx> dyn AstConv<'gcx, 'tcx>+'o {
 
         let output_ty = match decl.output {
             hir::Return(ref output) => self.ast_ty_to_ty(output),
-            hir::DefaultReturn(..) => tcx.mk_nil(),
+            hir::DefaultReturn(..) => tcx.mk_unit(),
         };
 
         debug!("ty_of_fn: output_ty={:?}", output_ty);

src/librustc_typeck/check/_match.rs

@@ -656,7 +656,7 @@ https://doc.rust-lang.org/reference/types.html#trait-objects");
                 // us to give better error messages (pointing to a usually better
                 // arm for inconsistent arms or to the whole match when a `()` type
                 // is required).
-                Expectation::ExpectHasType(ety) if ety != self.tcx.mk_nil() => ety,
+                Expectation::ExpectHasType(ety) if ety != self.tcx.mk_unit() => ety,
                 _ => self.next_ty_var(TypeVariableOrigin::MiscVariable(expr.span)),
             };
             CoerceMany::with_coercion_sites(coerce_first, arms)
@@ -677,14 +677,14 @@ https://doc.rust-lang.org/reference/types.html#trait-objects");
             // Handle the fallback arm of a desugared if-let like a missing else.
             let is_if_let_fallback = match match_src {
                 hir::MatchSource::IfLetDesugar { contains_else_clause: false } => {
-                    i == arms.len() - 1 && arm_ty.is_nil()
+                    i == arms.len() - 1 && arm_ty.is_unit()
                 }
                 _ => false
             };
 
             if is_if_let_fallback {
                 let cause = self.cause(expr.span, ObligationCauseCode::IfExpressionWithNoElse);
-                assert!(arm_ty.is_nil());
+                assert!(arm_ty.is_unit());
                 coercion.coerce_forced_unit(self, &cause, &mut |_| (), true);
             } else {
                 let cause = self.cause(expr.span, ObligationCauseCode::MatchExpressionArm {

src/librustc_typeck/check/coercion.rs

@@ -1077,7 +1077,7 @@ impl<'gcx, 'tcx, 'exprs, E> CoerceMany<'gcx, 'tcx, 'exprs, E>
         self.coerce_inner(fcx,
                           cause,
                           None,
-                          fcx.tcx.mk_nil(),
+                          fcx.tcx.mk_unit(),
                           Some(augment_error),
                           label_unit_as_expected)
     }
@@ -1146,8 +1146,8 @@ impl<'gcx, 'tcx, 'exprs, E> CoerceMany<'gcx, 'tcx, 'exprs, E>
             // `expression_ty` will be unit).
             //
             // Another example is `break` with no argument expression.
-            assert!(expression_ty.is_nil());
-            assert!(expression_ty.is_nil(), "if let hack without unit type");
+            assert!(expression_ty.is_unit());
+            assert!(expression_ty.is_unit(), "if let hack without unit type");
             fcx.at(cause, fcx.param_env)
                .eq_exp(label_expression_as_expected, expression_ty, self.merged_ty())
                .map(|infer_ok| {