1 files changed, 119 insertions, 0 deletions
diff --git a/compiler/rustc_middle/src/ty/parameterized.rs b/compiler/rustc_middle/src/ty/parameterized.rs
new file mode 100644
index 000000000..e189ee2fc
--- /dev/null
+++ b/compiler/rustc_middle/src/ty/parameterized.rs
@@ -0,0 +1,119 @@
+use rustc_hir::def_id::DefId;
+use rustc_index::vec::{Idx, IndexVec};
+
+use crate::middle::exported_symbols::ExportedSymbol;
+use crate::mir::Body;
+use crate::ty::abstract_const::Node;
+use crate::ty::{
+    self, Const, FnSig, GeneratorDiagnosticData, GenericPredicates, Predicate, TraitRef, Ty,
+};
+
+pub trait ParameterizedOverTcx: 'static {
+    #[allow(unused_lifetimes)]
+    type Value<'tcx>;
+}
+
+impl<T: ParameterizedOverTcx> ParameterizedOverTcx for &'static [T] {
+    type Value<'tcx> = &'tcx [T::Value<'tcx>];
+}
+
+impl<T: ParameterizedOverTcx> ParameterizedOverTcx for Option<T> {
+    type Value<'tcx> = Option<T::Value<'tcx>>;
+}
+
+impl<A: ParameterizedOverTcx, B: ParameterizedOverTcx> ParameterizedOverTcx for (A, B) {
+    type Value<'tcx> = (A::Value<'tcx>, B::Value<'tcx>);
+}
+
+impl<I: Idx + 'static, T: ParameterizedOverTcx> ParameterizedOverTcx for IndexVec<I, T> {
+    type Value<'tcx> = IndexVec<I, T::Value<'tcx>>;
+}
+
+impl<T: ParameterizedOverTcx> ParameterizedOverTcx for ty::Binder<'static, T> {
+    type Value<'tcx> = ty::Binder<'tcx, T::Value<'tcx>>;
+}
+
+#[macro_export]
+macro_rules! trivially_parameterized_over_tcx {
+    ($($ty:ty),+ $(,)?) => {
+        $(
+            impl $crate::ty::ParameterizedOverTcx for $ty {
+                #[allow(unused_lifetimes)]
+                type Value<'tcx> = $ty;
+            }
+        )*
+    }
+}
+
+trivially_parameterized_over_tcx! {
+    usize,
+    (),
+    u32,
+    std::string::String,
+    crate::metadata::ModChild,
+    crate::middle::codegen_fn_attrs::CodegenFnAttrs,
+    crate::middle::exported_symbols::SymbolExportInfo,
+    crate::mir::ConstQualifs,
+    ty::Generics,
+    ty::ImplPolarity,
+    ty::ReprOptions,
+    ty::TraitDef,
+    ty::Visibility,
+    ty::adjustment::CoerceUnsizedInfo,
+    ty::fast_reject::SimplifiedTypeGen<DefId>,
+    rustc_ast::Attribute,
+    rustc_ast::MacArgs,
+    rustc_attr::ConstStability,
+    rustc_attr::Deprecation,
+    rustc_attr::Stability,
+    rustc_hir::Constness,
+    rustc_hir::Defaultness,
+    rustc_hir::GeneratorKind,
+    rustc_hir::IsAsync,
+    rustc_hir::LangItem,
+    rustc_hir::def::DefKind,
+    rustc_hir::def_id::DefIndex,
+    rustc_hir::definitions::DefKey,
+    rustc_index::bit_set::FiniteBitSet<u32>,
+    rustc_session::cstore::ForeignModule,
+    rustc_session::cstore::LinkagePreference,
+    rustc_session::cstore::NativeLib,
+    rustc_span::DebuggerVisualizerFile,
+    rustc_span::ExpnData,
+    rustc_span::ExpnHash,
+    rustc_span::ExpnId,
+    rustc_span::SourceFile,
+    rustc_span::Span,
+    rustc_span::Symbol,
+    rustc_span::def_id::DefPathHash,
+    rustc_span::hygiene::SyntaxContextData,
+    rustc_span::symbol::Ident,
+    rustc_type_ir::Variance,
+}
+
+// HACK(compiler-errors): This macro rule can only take an ident,
+// not a path, due to parsing ambiguity reasons. That means we gotta
+// import all of these types above.
+#[macro_export]
+macro_rules! parameterized_over_tcx {
+    ($($ident:ident),+ $(,)?) => {
+        $(
+            impl $crate::ty::ParameterizedOverTcx for $ident<'static> {
+                type Value<'tcx> = $ident<'tcx>;
+            }
+        )*
+    }
+}
+
+parameterized_over_tcx! {
+    Ty,
+    FnSig,
+    GenericPredicates,
+    TraitRef,
+    Const,
+    Predicate,
+    GeneratorDiagnosticData,
+    Body,
+    Node,
+    ExportedSymbol,
+}