refactor(rustc_middle): Substs -> GenericArg

9 files changed, 73 insertions, 69 deletions

diff --git a/compiler/rustc_codegen_ssa/src/back/symbol_export.rs b/compiler/rustc_codegen_ssa/src/back/symbol_export.rs
index a8b6030ac85..406048bfe05 100644
--- a/compiler/rustc_codegen_ssa/src/back/symbol_export.rs
+++ b/compiler/rustc_codegen_ssa/src/back/symbol_export.rs
@@ -12,9 +12,9 @@ use rustc_middle::middle::exported_symbols::{
 };
 use rustc_middle::query::LocalCrate;
 use rustc_middle::query::{ExternProviders, Providers};
-use rustc_middle::ty::subst::{GenericArgKind, SubstsRef};
 use rustc_middle::ty::Instance;
 use rustc_middle::ty::{self, SymbolName, TyCtxt};
+use rustc_middle::ty::{GenericArgKind, GenericArgsRef};
 use rustc_session::config::{CrateType, OomStrategy};
 use rustc_target::spec::SanitizerSet;
 
@@ -342,9 +342,9 @@ fn exported_symbols_provider_local(
             }
 
             match *mono_item {
-                MonoItem::Fn(Instance { def: InstanceDef::Item(def), substs }) => {
-                    if substs.non_erasable_generics().next().is_some() {
-                        let symbol = ExportedSymbol::Generic(def, substs);
+                MonoItem::Fn(Instance { def: InstanceDef::Item(def), args }) => {
+                    if args.non_erasable_generics().next().is_some() {
+                        let symbol = ExportedSymbol::Generic(def, args);
                         symbols.push((
                             symbol,
                             SymbolExportInfo {
@@ -355,10 +355,10 @@ fn exported_symbols_provider_local(
                         ));
                     }
                 }
-                MonoItem::Fn(Instance { def: InstanceDef::DropGlue(_, Some(ty)), substs }) => {
+                MonoItem::Fn(Instance { def: InstanceDef::DropGlue(_, Some(ty)), args }) => {
                     // A little sanity-check
                     debug_assert_eq!(
-                        substs.non_erasable_generics().next(),
+                        args.non_erasable_generics().next(),
                         Some(GenericArgKind::Type(ty))
                     );
                     symbols.push((
@@ -386,7 +386,7 @@ fn exported_symbols_provider_local(
 fn upstream_monomorphizations_provider(
     tcx: TyCtxt<'_>,
     (): (),
-) -> DefIdMap<FxHashMap<SubstsRef<'_>, CrateNum>> {
+) -> DefIdMap<FxHashMap<GenericArgsRef<'_>, CrateNum>> {
     let cnums = tcx.crates(());
 
     let mut instances: DefIdMap<FxHashMap<_, _>> = Default::default();
@@ -395,11 +395,11 @@ fn upstream_monomorphizations_provider(
 
     for &cnum in cnums.iter() {
         for (exported_symbol, _) in tcx.exported_symbols(cnum).iter() {
-            let (def_id, substs) = match *exported_symbol {
-                ExportedSymbol::Generic(def_id, substs) => (def_id, substs),
+            let (def_id, args) = match *exported_symbol {
+                ExportedSymbol::Generic(def_id, args) => (def_id, args),
                 ExportedSymbol::DropGlue(ty) => {
                     if let Some(drop_in_place_fn_def_id) = drop_in_place_fn_def_id {
-                        (drop_in_place_fn_def_id, tcx.mk_substs(&[ty.into()]))
+                        (drop_in_place_fn_def_id, tcx.mk_args(&[ty.into()]))
                     } else {
                         // `drop_in_place` in place does not exist, don't try
                         // to use it.
@@ -414,9 +414,9 @@ fn upstream_monomorphizations_provider(
                 }
             };
 
-            let substs_map = instances.entry(def_id).or_default();
+            let args_map = instances.entry(def_id).or_default();
 
-            match substs_map.entry(substs) {
+            match args_map.entry(args) {
                 Occupied(mut e) => {
                     // If there are multiple monomorphizations available,
                     // we select one deterministically.
@@ -438,17 +438,17 @@ fn upstream_monomorphizations_provider(
 fn upstream_monomorphizations_for_provider(
     tcx: TyCtxt<'_>,
     def_id: DefId,
-) -> Option<&FxHashMap<SubstsRef<'_>, CrateNum>> {
+) -> Option<&FxHashMap<GenericArgsRef<'_>, CrateNum>> {
     debug_assert!(!def_id.is_local());
     tcx.upstream_monomorphizations(()).get(&def_id)
 }
 
 fn upstream_drop_glue_for_provider<'tcx>(
     tcx: TyCtxt<'tcx>,
-    substs: SubstsRef<'tcx>,
+    args: GenericArgsRef<'tcx>,
 ) -> Option<CrateNum> {
     if let Some(def_id) = tcx.lang_items().drop_in_place_fn() {
-        tcx.upstream_monomorphizations_for(def_id).and_then(|monos| monos.get(&substs).cloned())
+        tcx.upstream_monomorphizations_for(def_id).and_then(|monos| monos.get(&args).cloned())
     } else {
         None
     }
@@ -521,10 +521,10 @@ pub fn symbol_name_for_instance_in_crate<'tcx>(
                 instantiating_crate,
             )
         }
-        ExportedSymbol::Generic(def_id, substs) => {
+        ExportedSymbol::Generic(def_id, args) => {
             rustc_symbol_mangling::symbol_name_for_instance_in_crate(
                 tcx,
-                Instance::new(def_id, substs),
+                Instance::new(def_id, args),
                 instantiating_crate,
             )
         }
@@ -533,7 +533,7 @@ pub fn symbol_name_for_instance_in_crate<'tcx>(
                 tcx,
                 ty::Instance {
                     def: ty::InstanceDef::ThreadLocalShim(def_id),
-                    substs: ty::InternalSubsts::empty(),
+                    args: ty::GenericArgs::empty(),
                 },
                 instantiating_crate,
             )
@@ -580,7 +580,7 @@ pub fn linking_symbol_name_for_instance_in_crate<'tcx>(
             None
         }
         ExportedSymbol::NonGeneric(def_id) => Some(Instance::mono(tcx, def_id)),
-        ExportedSymbol::Generic(def_id, substs) => Some(Instance::new(def_id, substs)),
+        ExportedSymbol::Generic(def_id, args) => Some(Instance::new(def_id, args)),
         // DropGlue always use the Rust calling convention and thus follow the target's default
         // symbol decoration scheme.
         ExportedSymbol::DropGlue(..) => None,
diff --git a/compiler/rustc_codegen_ssa/src/base.rs b/compiler/rustc_codegen_ssa/src/base.rs
index 9133601ecd1..dc862803274 100644
--- a/compiler/rustc_codegen_ssa/src/base.rs
+++ b/compiler/rustc_codegen_ssa/src/base.rs
@@ -499,7 +499,7 @@ pub fn maybe_create_entry_wrapper<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
                     cx.tcx(),
                     ty::ParamEnv::reveal_all(),
                     start_def_id,
-                    cx.tcx().mk_substs(&[main_ret_ty.into()]),
+                    cx.tcx().mk_args(&[main_ret_ty.into()]),
                 )
                 .unwrap()
                 .unwrap(),
diff --git a/compiler/rustc_codegen_ssa/src/debuginfo/type_names.rs b/compiler/rustc_codegen_ssa/src/debuginfo/type_names.rs
index e91f7b86e5e..64f799bb1e6 100644
--- a/compiler/rustc_codegen_ssa/src/debuginfo/type_names.rs
+++ b/compiler/rustc_codegen_ssa/src/debuginfo/type_names.rs
@@ -17,8 +17,8 @@ use rustc_hir::def_id::DefId;
 use rustc_hir::definitions::{DefPathData, DefPathDataName, DisambiguatedDefPathData};
 use rustc_hir::{AsyncGeneratorKind, GeneratorKind, Mutability};
 use rustc_middle::ty::layout::{IntegerExt, TyAndLayout};
-use rustc_middle::ty::subst::{GenericArgKind, SubstsRef};
 use rustc_middle::ty::{self, ExistentialProjection, ParamEnv, Ty, TyCtxt};
+use rustc_middle::ty::{GenericArgKind, GenericArgsRef};
 use rustc_target::abi::Integer;
 use smallvec::SmallVec;
 
@@ -77,7 +77,7 @@ fn push_debuginfo_type_name<'tcx>(
         ty::Uint(uint_ty) => output.push_str(uint_ty.name_str()),
         ty::Float(float_ty) => output.push_str(float_ty.name_str()),
         ty::Foreign(def_id) => push_item_name(tcx, def_id, qualified, output),
-        ty::Adt(def, substs) => {
+        ty::Adt(def, args) => {
             // `layout_for_cpp_like_fallback` will be `Some` if we want to use the fallback encoding.
             let layout_for_cpp_like_fallback = if cpp_like_debuginfo && def.is_enum() {
                 match tcx.layout_of(ParamEnv::reveal_all().and(t)) {
@@ -106,14 +106,14 @@ fn push_debuginfo_type_name<'tcx>(
                     ty_and_layout,
                     &|output, visited| {
                         push_item_name(tcx, def.did(), true, output);
-                        push_generic_params_internal(tcx, substs, output, visited);
+                        push_generic_params_internal(tcx, args, output, visited);
                     },
                     output,
                     visited,
                 );
             } else {
                 push_item_name(tcx, def.did(), qualified, output);
-                push_generic_params_internal(tcx, substs, output, visited);
+                push_generic_params_internal(tcx, args, output, visited);
             }
         }
         ty::Tuple(component_types) => {
@@ -238,7 +238,7 @@ fn push_debuginfo_type_name<'tcx>(
                     tcx.normalize_erasing_late_bound_regions(ty::ParamEnv::reveal_all(), principal);
                 push_item_name(tcx, principal.def_id, qualified, output);
                 let principal_has_generic_params =
-                    push_generic_params_internal(tcx, principal.substs, output, visited);
+                    push_generic_params_internal(tcx, principal.args, output, visited);
 
                 let projection_bounds: SmallVec<[_; 4]> = trait_data
                     .projection_bounds()
@@ -393,7 +393,7 @@ fn push_debuginfo_type_name<'tcx>(
             // processing
             visited.remove(&t);
         }
-        ty::Closure(def_id, substs) | ty::Generator(def_id, substs, ..) => {
+        ty::Closure(def_id, args) | ty::Generator(def_id, args, ..) => {
             // Name will be "{closure_env#0}<T1, T2, ...>", "{generator_env#0}<T1, T2, ...>", or
             // "{async_fn_env#0}<T1, T2, ...>", etc.
             // In the case of cpp-like debuginfo, the name additionally gets wrapped inside of
@@ -403,13 +403,13 @@ fn push_debuginfo_type_name<'tcx>(
                 msvc_enum_fallback(
                     ty_and_layout,
                     &|output, visited| {
-                        push_closure_or_generator_name(tcx, def_id, substs, true, output, visited);
+                        push_closure_or_generator_name(tcx, def_id, args, true, output, visited);
                     },
                     output,
                     visited,
                 );
             } else {
-                push_closure_or_generator_name(tcx, def_id, substs, qualified, output, visited);
+                push_closure_or_generator_name(tcx, def_id, args, qualified, output, visited);
             }
         }
         // Type parameters from polymorphized functions.
@@ -516,7 +516,7 @@ pub fn compute_debuginfo_vtable_name<'tcx>(
             tcx.normalize_erasing_late_bound_regions(ty::ParamEnv::reveal_all(), trait_ref);
         push_item_name(tcx, trait_ref.def_id, true, &mut vtable_name);
         visited.clear();
-        push_generic_params_internal(tcx, trait_ref.substs, &mut vtable_name, &mut visited);
+        push_generic_params_internal(tcx, trait_ref.args, &mut vtable_name, &mut visited);
     } else {
         vtable_name.push('_');
     }
@@ -609,21 +609,21 @@ fn push_unqualified_item_name(
 
 fn push_generic_params_internal<'tcx>(
     tcx: TyCtxt<'tcx>,
-    substs: SubstsRef<'tcx>,
+    args: GenericArgsRef<'tcx>,
     output: &mut String,
     visited: &mut FxHashSet<Ty<'tcx>>,
 ) -> bool {
-    if substs.non_erasable_generics().next().is_none() {
+    if args.non_erasable_generics().next().is_none() {
         return false;
     }
 
-    debug_assert_eq!(substs, tcx.normalize_erasing_regions(ty::ParamEnv::reveal_all(), substs));
+    debug_assert_eq!(args, tcx.normalize_erasing_regions(ty::ParamEnv::reveal_all(), args));
 
     let cpp_like_debuginfo = cpp_like_debuginfo(tcx);
 
     output.push('<');
 
-    for type_parameter in substs.non_erasable_generics() {
+    for type_parameter in args.non_erasable_generics() {
         match type_parameter {
             GenericArgKind::Type(type_parameter) => {
                 push_debuginfo_type_name(tcx, type_parameter, true, output, visited);
@@ -688,16 +688,20 @@ fn push_const_param<'tcx>(tcx: TyCtxt<'tcx>, ct: ty::Const<'tcx>, output: &mut S
     .unwrap();
 }
 
-pub fn push_generic_params<'tcx>(tcx: TyCtxt<'tcx>, substs: SubstsRef<'tcx>, output: &mut String) {
+pub fn push_generic_params<'tcx>(
+    tcx: TyCtxt<'tcx>,
+    args: GenericArgsRef<'tcx>,
+    output: &mut String,
+) {
     let _prof = tcx.prof.generic_activity("compute_debuginfo_type_name");
     let mut visited = FxHashSet::default();
-    push_generic_params_internal(tcx, substs, output, &mut visited);
+    push_generic_params_internal(tcx, args, output, &mut visited);
 }
 
 fn push_closure_or_generator_name<'tcx>(
     tcx: TyCtxt<'tcx>,
     def_id: DefId,
-    substs: SubstsRef<'tcx>,
+    args: GenericArgsRef<'tcx>,
     qualified: bool,
     output: &mut String,
     visited: &mut FxHashSet<Ty<'tcx>>,
@@ -731,10 +735,10 @@ fn push_closure_or_generator_name<'tcx>(
     let enclosing_fn_def_id = tcx.typeck_root_def_id(def_id);
     let generics = tcx.generics_of(enclosing_fn_def_id);
 
-    // Truncate the substs to the length of the above generics. This will cut off
+    // Truncate the args to the length of the above generics. This will cut off
     // anything closure- or generator-specific.
-    let substs = substs.truncate_to(tcx, generics);
-    push_generic_params_internal(tcx, substs, output, visited);
+    let args = args.truncate_to(tcx, generics);
+    push_generic_params_internal(tcx, args, output, visited);
 }
 
 fn push_close_angle_bracket(cpp_like_debuginfo: bool, output: &mut String) {
diff --git a/compiler/rustc_codegen_ssa/src/meth.rs b/compiler/rustc_codegen_ssa/src/meth.rs
index a8b935bd65c..9abe7b25d0e 100644
--- a/compiler/rustc_codegen_ssa/src/meth.rs
+++ b/compiler/rustc_codegen_ssa/src/meth.rs
@@ -1,6 +1,6 @@
 use crate::traits::*;
 
-use rustc_middle::ty::{self, subst::GenericArgKind, Ty};
+use rustc_middle::ty::{self, GenericArgKind, Ty};
 use rustc_session::config::Lto;
 use rustc_symbol_mangling::typeid_for_trait_ref;
 use rustc_target::abi::call::FnAbi;
diff --git a/compiler/rustc_codegen_ssa/src/mir/block.rs b/compiler/rustc_codegen_ssa/src/mir/block.rs
index 9d1b3ce8266..269c12e7a68 100644
--- a/compiler/rustc_codegen_ssa/src/mir/block.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/block.rs
@@ -491,7 +491,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                     //
                     let virtual_drop = Instance {
                         def: ty::InstanceDef::Virtual(drop_fn.def_id(), 0),
-                        substs: drop_fn.substs,
+                        args: drop_fn.args,
                     };
                     debug!("ty = {:?}", ty);
                     debug!("drop_fn = {:?}", drop_fn);
@@ -531,7 +531,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                     // SO THEN WE CAN USE THE ABOVE CODE.
                     let virtual_drop = Instance {
                         def: ty::InstanceDef::Virtual(drop_fn.def_id(), 0),
-                        substs: drop_fn.substs,
+                        args: drop_fn.args,
                     };
                     debug!("ty = {:?}", ty);
                     debug!("drop_fn = {:?}", drop_fn);
@@ -687,7 +687,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         // which mentions the offending type, even from a const context.
         let panic_intrinsic = intrinsic.and_then(|s| ValidityRequirement::from_intrinsic(s));
         if let Some(requirement) = panic_intrinsic {
-            let ty = instance.unwrap().substs.type_at(0);
+            let ty = instance.unwrap().args.type_at(0);
 
             let do_panic = !bx
                 .tcx()
@@ -760,13 +760,13 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         let callee = self.codegen_operand(bx, func);
 
         let (instance, mut llfn) = match *callee.layout.ty.kind() {
-            ty::FnDef(def_id, substs) => (
+            ty::FnDef(def_id, args) => (
                 Some(
                     ty::Instance::expect_resolve(
                         bx.tcx(),
                         ty::ParamEnv::reveal_all(),
                         def_id,
-                        substs,
+                        args,
                     )
                     .polymorphize(bx.tcx()),
                 ),
@@ -1125,12 +1125,12 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 }
                 mir::InlineAsmOperand::SymFn { ref value } => {
                     let literal = self.monomorphize(value.literal);
-                    if let ty::FnDef(def_id, substs) = *literal.ty().kind() {
+                    if let ty::FnDef(def_id, args) = *literal.ty().kind() {
                         let instance = ty::Instance::resolve_for_fn_ptr(
                             bx.tcx(),
                             ty::ParamEnv::reveal_all(),
                             def_id,
-                            substs,
+                            args,
                         )
                         .unwrap();
                         InlineAsmOperandRef::SymFn { instance }
diff --git a/compiler/rustc_codegen_ssa/src/mir/intrinsic.rs b/compiler/rustc_codegen_ssa/src/mir/intrinsic.rs
index 8a65dd593b8..18201abd631 100644
--- a/compiler/rustc_codegen_ssa/src/mir/intrinsic.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/intrinsic.rs
@@ -64,7 +64,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
     ) {
         let callee_ty = instance.ty(bx.tcx(), ty::ParamEnv::reveal_all());
 
-        let ty::FnDef(def_id, substs) = *callee_ty.kind() else {
+        let ty::FnDef(def_id, fn_args) = *callee_ty.kind() else {
             bug!("expected fn item type, found {}", callee_ty);
         };
 
@@ -87,7 +87,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             sym::va_start => bx.va_start(args[0].immediate()),
             sym::va_end => bx.va_end(args[0].immediate()),
             sym::size_of_val => {
-                let tp_ty = substs.type_at(0);
+                let tp_ty = fn_args.type_at(0);
                 if let OperandValue::Pair(_, meta) = args[0].val {
                     let (llsize, _) = glue::size_and_align_of_dst(bx, tp_ty, Some(meta));
                     llsize
@@ -96,7 +96,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 }
             }
             sym::min_align_of_val => {
-                let tp_ty = substs.type_at(0);
+                let tp_ty = fn_args.type_at(0);
                 if let OperandValue::Pair(_, meta) = args[0].val {
                     let (_, llalign) = glue::size_and_align_of_dst(bx, tp_ty, Some(meta));
                     llalign
@@ -136,7 +136,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 OperandRef::from_const(bx, value, ret_ty).immediate_or_packed_pair(bx)
             }
             sym::arith_offset => {
-                let ty = substs.type_at(0);
+                let ty = fn_args.type_at(0);
                 let layout = bx.layout_of(ty);
                 let ptr = args[0].immediate();
                 let offset = args[1].immediate();
@@ -147,7 +147,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                     bx,
                     true,
                     false,
-                    substs.type_at(0),
+                    fn_args.type_at(0),
                     args[1].immediate(),
                     args[0].immediate(),
                     args[2].immediate(),
@@ -158,7 +158,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 memset_intrinsic(
                     bx,
                     false,
-                    substs.type_at(0),
+                    fn_args.type_at(0),
                     args[0].immediate(),
                     args[1].immediate(),
                     args[2].immediate(),
@@ -171,7 +171,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                     bx,
                     false,
                     true,
-                    substs.type_at(0),
+                    fn_args.type_at(0),
                     args[0].immediate(),
                     args[1].immediate(),
                     args[2].immediate(),
@@ -183,7 +183,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                     bx,
                     true,
                     true,
-                    substs.type_at(0),
+                    fn_args.type_at(0),
                     args[0].immediate(),
                     args[1].immediate(),
                     args[2].immediate(),
@@ -194,7 +194,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 memset_intrinsic(
                     bx,
                     true,
-                    substs.type_at(0),
+                    fn_args.type_at(0),
                     args[0].immediate(),
                     args[1].immediate(),
                     args[2].immediate(),
@@ -307,7 +307,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                         let Some((success, failure)) = ordering.split_once('_') else {
                             bx.sess().emit_fatal(errors::AtomicCompareExchange);
                         };
-                        let ty = substs.type_at(0);
+                        let ty = fn_args.type_at(0);
                         if int_type_width_signed(ty, bx.tcx()).is_some() || ty.is_unsafe_ptr() {
                             let weak = instruction == "cxchgweak";
                             let mut dst = args[0].immediate();
@@ -338,7 +338,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                     }
 
                     "load" => {
-                        let ty = substs.type_at(0);
+                        let ty = fn_args.type_at(0);
                         if int_type_width_signed(ty, bx.tcx()).is_some() || ty.is_unsafe_ptr() {
                             let layout = bx.layout_of(ty);
                             let size = layout.size;
@@ -361,7 +361,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                     }
 
                     "store" => {
-                        let ty = substs.type_at(0);
+                        let ty = fn_args.type_at(0);
                         if int_type_width_signed(ty, bx.tcx()).is_some() || ty.is_unsafe_ptr() {
                             let size = bx.layout_of(ty).size;
                             let mut val = args[1].immediate();
@@ -407,7 +407,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                             _ => bx.sess().emit_fatal(errors::UnknownAtomicOperation),
                         };
 
-                        let ty = substs.type_at(0);
+                        let ty = fn_args.type_at(0);
                         if int_type_width_signed(ty, bx.tcx()).is_some() || ty.is_unsafe_ptr() {
                             let mut ptr = args[0].immediate();
                             let mut val = args[1].immediate();
@@ -439,7 +439,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             }
 
             sym::ptr_offset_from | sym::ptr_offset_from_unsigned => {
-                let ty = substs.type_at(0);
+                let ty = fn_args.type_at(0);
                 let pointee_size = bx.layout_of(ty).size;
 
                 let a = args[0].immediate();
diff --git a/compiler/rustc_codegen_ssa/src/mir/mod.rs b/compiler/rustc_codegen_ssa/src/mir/mod.rs
index 9ff6a249748..3464f910829 100644
--- a/compiler/rustc_codegen_ssa/src/mir/mod.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/mod.rs
@@ -159,7 +159,7 @@ pub fn codegen_mir<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
     cx: &'a Bx::CodegenCx,
     instance: Instance<'tcx>,
 ) {
-    assert!(!instance.substs.has_infer());
+    assert!(!instance.args.has_infer());
 
     let llfn = cx.get_fn(instance);
 
diff --git a/compiler/rustc_codegen_ssa/src/mir/rvalue.rs b/compiler/rustc_codegen_ssa/src/mir/rvalue.rs
index 956f03d2578..1f90a28eb8e 100644
--- a/compiler/rustc_codegen_ssa/src/mir/rvalue.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/rvalue.rs
@@ -417,12 +417,12 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                     }
                     mir::CastKind::PointerCoercion(PointerCoercion::ReifyFnPointer) => {
                         match *operand.layout.ty.kind() {
-                            ty::FnDef(def_id, substs) => {
+                            ty::FnDef(def_id, args) => {
                                 let instance = ty::Instance::resolve_for_fn_ptr(
                                     bx.tcx(),
                                     ty::ParamEnv::reveal_all(),
                                     def_id,
-                                    substs,
+                                    args,
                                 )
                                 .unwrap()
                                 .polymorphize(bx.cx().tcx());
@@ -433,11 +433,11 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                     }
                     mir::CastKind::PointerCoercion(PointerCoercion::ClosureFnPointer(_)) => {
                         match *operand.layout.ty.kind() {
-                            ty::Closure(def_id, substs) => {
+                            ty::Closure(def_id, args) => {
                                 let instance = Instance::resolve_closure(
                                     bx.cx().tcx(),
                                     def_id,
-                                    substs,
+                                    args,
                                     ty::ClosureKind::FnOnce,
                                 )
                                 .expect("failed to normalize and resolve closure during codegen")
@@ -711,7 +711,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 {
                     let instance = ty::Instance {
                         def: ty::InstanceDef::ThreadLocalShim(def_id),
-                        substs: ty::InternalSubsts::empty(),
+                        args: ty::GenericArgs::empty(),
                     };
                     let fn_ptr = bx.get_fn_addr(instance);
                     let fn_abi = bx.fn_abi_of_instance(instance, ty::List::empty());
diff --git a/compiler/rustc_codegen_ssa/src/mono_item.rs b/compiler/rustc_codegen_ssa/src/mono_item.rs
index 27da33581a1..b72a1a07866 100644
--- a/compiler/rustc_codegen_ssa/src/mono_item.rs
+++ b/compiler/rustc_codegen_ssa/src/mono_item.rs
@@ -64,7 +64,7 @@ impl<'a, 'tcx: 'a> MonoItemExt<'a, 'tcx> for MonoItem<'tcx> {
                                     .typeck_body(anon_const.body)
                                     .node_type(anon_const.hir_id);
                                 let instance = match ty.kind() {
-                                    &ty::FnDef(def_id, substs) => Instance::new(def_id, substs),
+                                    &ty::FnDef(def_id, args) => Instance::new(def_id, args),
                                     _ => span_bug!(*op_sp, "asm sym is not a function"),
                                 };
 
@@ -138,7 +138,7 @@ impl<'a, 'tcx: 'a> MonoItemExt<'a, 'tcx> for MonoItem<'tcx> {
     fn to_raw_string(&self) -> String {
         match *self {
             MonoItem::Fn(instance) => {
-                format!("Fn({:?}, {})", instance.def, instance.substs.as_ptr().addr())
+                format!("Fn({:?}, {})", instance.def, instance.args.as_ptr().addr())
             }
             MonoItem::Static(id) => format!("Static({:?})", id),
             MonoItem::GlobalAsm(id) => format!("GlobalAsm({:?})", id),