Auto merge of #108112 - nnethercote:clarify-iterator-interners, r=oli-obk,compiler-errors

Clarify iterator interners

I found the iterator interners very confusing. This PR clarifies things.

r? `@compiler-errors`

Author: bors

compiler/rustc_borrowck/src/type_check/mod.rs

@@ -2589,7 +2589,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
             DefKind::InlineConst => substs.as_inline_const().parent_substs(),
             other => bug!("unexpected item {:?}", other),
         };
-        let parent_substs = tcx.mk_substs(parent_substs.iter());
+        let parent_substs = tcx.intern_substs(parent_substs);
 
         assert_eq!(typeck_root_substs.len(), parent_substs.len());
         if let Err(_) = self.eq_substs(

compiler/rustc_codegen_cranelift/src/codegen_i128.rs

@@ -56,7 +56,7 @@ pub(crate) fn maybe_codegen<'tcx>(
                     Some(fx.easy_call("__multi3", &[lhs, rhs], val_ty))
                 }
             } else {
-                let out_ty = fx.tcx.mk_tup([lhs.layout().ty, fx.tcx.types.bool].iter());
+                let out_ty = fx.tcx.intern_tup(&[lhs.layout().ty, fx.tcx.types.bool]);
                 let oflow = CPlace::new_stack_slot(fx, fx.layout_of(fx.tcx.types.i32));
                 let lhs = lhs.load_scalar(fx);
                 let rhs = rhs.load_scalar(fx);
@@ -78,7 +78,7 @@ pub(crate) fn maybe_codegen<'tcx>(
         }
         BinOp::Add | BinOp::Sub | BinOp::Mul => {
             assert!(checked);
-            let out_ty = fx.tcx.mk_tup([lhs.layout().ty, fx.tcx.types.bool].iter());
+            let out_ty = fx.tcx.intern_tup(&[lhs.layout().ty, fx.tcx.types.bool]);
             let out_place = CPlace::new_stack_slot(fx, fx.layout_of(out_ty));
             let (param_types, args) = if fx.tcx.sess.target.is_like_windows {
                 let (lhs_ptr, lhs_extra) = lhs.force_stack(fx);

compiler/rustc_codegen_cranelift/src/intrinsics/llvm_x86.rs

@@ -191,7 +191,7 @@ fn llvm_add_sub<'tcx>(
     // carry0 | carry1 -> carry or borrow respectively
     let cb_out = fx.bcx.ins().bor(cb0, cb1);
 
-    let layout = fx.layout_of(fx.tcx.mk_tup([fx.tcx.types.u8, fx.tcx.types.u64].iter()));
+    let layout = fx.layout_of(fx.tcx.intern_tup(&[fx.tcx.types.u8, fx.tcx.types.u64]));
     let val = CValue::by_val_pair(cb_out, c, layout);
     ret.write_cvalue(fx, val);
 }

compiler/rustc_codegen_cranelift/src/main_shim.rs

@@ -119,7 +119,7 @@ pub(crate) fn maybe_create_entry_wrapper(
                     tcx,
                     ParamEnv::reveal_all(),
                     report.def_id,
-                    tcx.mk_substs([GenericArg::from(main_ret_ty)].iter()),
+                    tcx.intern_substs(&[GenericArg::from(main_ret_ty)]),
                 )
                 .unwrap()
                 .unwrap()

compiler/rustc_codegen_cranelift/src/num.rs

@@ -289,7 +289,7 @@ pub(crate) fn codegen_checked_int_binop<'tcx>(
         _ => bug!("binop {:?} on checked int/uint lhs: {:?} rhs: {:?}", bin_op, in_lhs, in_rhs),
     };
 
-    let out_layout = fx.layout_of(fx.tcx.mk_tup([in_lhs.layout().ty, fx.tcx.types.bool].iter()));
+    let out_layout = fx.layout_of(fx.tcx.intern_tup(&[in_lhs.layout().ty, fx.tcx.types.bool]));
     CValue::by_val_pair(res, has_overflow, out_layout)
 }
 

compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs

@@ -27,8 +27,6 @@ use rustc_middle::ty::Instance;
 use std::cell::RefCell;
 use std::ffi::CString;
 
-use std::iter;
-
 pub mod mapgen;
 
 const UNUSED_FUNCTION_COUNTER_ID: CounterValueReference = CounterValueReference::START;
@@ -201,7 +199,7 @@ fn declare_unused_fn<'tcx>(cx: &CodegenCx<'_, 'tcx>, def_id: DefId) -> Instance<
         tcx.symbol_name(instance).name,
         cx.fn_abi_of_fn_ptr(
             ty::Binder::dummy(tcx.mk_fn_sig(
-                iter::once(tcx.mk_unit()),
+                [tcx.mk_unit()],
                 tcx.mk_unit(),
                 false,
                 hir::Unsafety::Unsafe,

compiler/rustc_codegen_llvm/src/intrinsic.rs

@@ -22,7 +22,6 @@ use rustc_target::abi::{self, Align, HasDataLayout, Primitive};
 use rustc_target::spec::{HasTargetSpec, PanicStrategy};
 
 use std::cmp::Ordering;
-use std::iter;
 
 fn get_simple_intrinsic<'ll>(
     cx: &CodegenCx<'ll, '_>,
@@ -798,23 +797,23 @@ fn get_rust_try_fn<'ll, 'tcx>(
     let i8p = tcx.mk_mut_ptr(tcx.types.i8);
     // `unsafe fn(*mut i8) -> ()`
     let try_fn_ty = tcx.mk_fn_ptr(ty::Binder::dummy(tcx.mk_fn_sig(
-        iter::once(i8p),
+        [i8p],
         tcx.mk_unit(),
         false,
         hir::Unsafety::Unsafe,
         Abi::Rust,
     )));
     // `unsafe fn(*mut i8, *mut i8) -> ()`
     let catch_fn_ty = tcx.mk_fn_ptr(ty::Binder::dummy(tcx.mk_fn_sig(
-        [i8p, i8p].iter().cloned(),
+        [i8p, i8p],
         tcx.mk_unit(),
         false,
         hir::Unsafety::Unsafe,
         Abi::Rust,
     )));
     // `unsafe fn(unsafe fn(*mut i8) -> (), *mut i8, unsafe fn(*mut i8, *mut i8) -> ()) -> i32`
     let rust_fn_sig = ty::Binder::dummy(cx.tcx.mk_fn_sig(
-        [try_fn_ty, i8p, catch_fn_ty].into_iter(),
+        [try_fn_ty, i8p, catch_fn_ty],
         tcx.types.i32,
         false,
         hir::Unsafety::Unsafe,

compiler/rustc_const_eval/src/interpret/intrinsics/caller_location.rs

@@ -96,7 +96,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         let loc_ty = self
             .tcx
             .type_of(self.tcx.require_lang_item(LangItem::PanicLocation, None))
-            .subst(*self.tcx, self.tcx.mk_substs([self.tcx.lifetimes.re_erased.into()].iter()));
+            .subst(*self.tcx, self.tcx.intern_substs(&[self.tcx.lifetimes.re_erased.into()]));
         let loc_layout = self.layout_of(loc_ty).unwrap();
         let location = self.allocate(loc_layout, MemoryKind::CallerLocation).unwrap();
 

compiler/rustc_hir_analysis/src/astconv/mod.rs

@@ -1608,7 +1608,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
             .collect::<SmallVec<[_; 8]>>();
         v.sort_by(|a, b| a.skip_binder().stable_cmp(tcx, &b.skip_binder()));
         v.dedup();
-        let existential_predicates = tcx.mk_poly_existential_predicates(v.into_iter());
+        let existential_predicates = tcx.intern_poly_existential_predicates(&v);
 
         // Use explicitly-specified region bound.
         let region_bound = if !lifetime.is_elided() {
@@ -3109,7 +3109,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
 
         debug!(?output_ty);
 
-        let fn_ty = tcx.mk_fn_sig(input_tys.into_iter(), output_ty, decl.c_variadic, unsafety, abi);
+        let fn_ty = tcx.mk_fn_sig(input_tys, output_ty, decl.c_variadic, unsafety, abi);
         let bare_fn_ty = ty::Binder::bind_with_vars(fn_ty, bound_vars);
 
         if !self.allow_ty_infer() && !(visitor.0.is_empty() && infer_replacements.is_empty()) {

compiler/rustc_hir_analysis/src/check/compare_impl_item.rs

@@ -1936,7 +1936,7 @@ pub(super) fn check_type_bounds<'tcx>(
             .into()
         }
     });
-    let bound_vars = tcx.mk_bound_variable_kinds(bound_vars.into_iter());
+    let bound_vars = tcx.intern_bound_variable_kinds(&bound_vars);
     let impl_ty_substs = tcx.intern_substs(&substs);
     let container_id = impl_ty.container_id(tcx);