diff --git a/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs b/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs
index 61e49fab6ff88..833604c533cf1 100644
--- a/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs
+++ b/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs
@@ -25,7 +25,7 @@ use rustc_data_structures::sync::Lrc;
 use rustc_hir::def_id::{DefId, DefIdMap};
 use rustc_index::vec::IndexVec;
 use rustc_middle::mir;
-use rustc_middle::ty::layout::{HasTyCtxt, LayoutOf};
+use rustc_middle::ty::layout::LayoutOf;
 use rustc_middle::ty::subst::{GenericArgKind, SubstsRef};
 use rustc_middle::ty::{self, Instance, ParamEnv, Ty, TypeFoldable};
 use rustc_session::config::{self, DebugInfo};
@@ -307,9 +307,11 @@ impl<'ll, 'tcx> DebugInfoMethods<'tcx> for CodegenCx<'ll, 'tcx> {
         fn_abi: &FnAbi<'tcx, Ty<'tcx>>,
         maybe_definition_llfn: Option<&'ll Value>,
     ) -> &'ll DIScope {
+        let tcx = self.tcx;
+
         let def_id = instance.def_id();
         let containing_scope = get_containing_scope(self, instance);
-        let span = self.tcx.def_span(def_id);
+        let span = tcx.def_span(def_id);
         let loc = self.lookup_debug_loc(span.lo());
         let file_metadata = file_metadata(self, &loc.file);
 
@@ -319,16 +321,24 @@ impl<'ll, 'tcx> DebugInfoMethods<'tcx> for CodegenCx<'ll, 'tcx> {
         };
 
         let mut name = String::new();
-        type_names::push_item_name(self.tcx(), def_id, false, &mut name);
+        type_names::push_item_name(tcx, def_id, false, &mut name);
 
         // Find the enclosing function, in case this is a closure.
-        let enclosing_fn_def_id = self.tcx().typeck_root_def_id(def_id);
+        let enclosing_fn_def_id = tcx.typeck_root_def_id(def_id);
+
+        // We look up the generics of the enclosing function and truncate the substs
+        // to their length in order to cut off extra stuff that might be in there for
+        // closures or generators.
+        let generics = tcx.generics_of(enclosing_fn_def_id);
+        let substs = instance.substs.truncate_to(tcx, generics);
+
+        type_names::push_generic_params(
+            tcx,
+            tcx.normalize_erasing_regions(ty::ParamEnv::reveal_all(), substs),
+            &mut name,
+        );
 
-        // Get_template_parameters() will append a `<...>` clause to the function
-        // name if necessary.
-        let generics = self.tcx().generics_of(enclosing_fn_def_id);
-        let substs = instance.substs.truncate_to(self.tcx(), generics);
-        let template_parameters = get_template_parameters(self, generics, substs, &mut name);
+        let template_parameters = get_template_parameters(self, generics, substs);
 
         let linkage_name = &mangled_name_of_instance(self, instance).name;
         // Omit the linkage_name if it is the same as subprogram name.
@@ -350,7 +360,7 @@ impl<'ll, 'tcx> DebugInfoMethods<'tcx> for CodegenCx<'ll, 'tcx> {
         if self.sess().opts.optimize != config::OptLevel::No {
             spflags |= DISPFlags::SPFlagOptimized;
         }
-        if let Some((id, _)) = self.tcx.entry_fn(()) {
+        if let Some((id, _)) = tcx.entry_fn(()) {
             if id == def_id {
                 spflags |= DISPFlags::SPFlagMainSubprogram;
             }
@@ -429,14 +439,7 @@ impl<'ll, 'tcx> DebugInfoMethods<'tcx> for CodegenCx<'ll, 'tcx> {
             cx: &CodegenCx<'ll, 'tcx>,
             generics: &ty::Generics,
             substs: SubstsRef<'tcx>,
-            name_to_append_suffix_to: &mut String,
         ) -> &'ll DIArray {
-            type_names::push_generic_params(
-                cx.tcx,
-                cx.tcx.normalize_erasing_regions(ty::ParamEnv::reveal_all(), substs),
-                name_to_append_suffix_to,
-            );
-
             if substs.types().next().is_none() {
                 return create_DIArray(DIB(cx), &[]);
             }
diff --git a/compiler/rustc_codegen_ssa/src/debuginfo/type_names.rs b/compiler/rustc_codegen_ssa/src/debuginfo/type_names.rs
index 9687fd09a53bc..831c34d8f1f60 100644
--- a/compiler/rustc_codegen_ssa/src/debuginfo/type_names.rs
+++ b/compiler/rustc_codegen_ssa/src/debuginfo/type_names.rs
@@ -13,9 +13,9 @@
 
 use rustc_data_structures::fx::FxHashSet;
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
-use rustc_hir as hir;
 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;
 use rustc_middle::ty::subst::{GenericArgKind, SubstsRef};
 use rustc_middle::ty::{self, AdtDef, ExistentialProjection, Ty, TyCtxt};
@@ -102,14 +102,14 @@ fn push_debuginfo_type_name<'tcx>(
         ty::RawPtr(ty::TypeAndMut { ty: inner_type, mutbl }) => {
             if cpp_like_debuginfo {
                 match mutbl {
-                    hir::Mutability::Not => output.push_str("ptr_const$<"),
-                    hir::Mutability::Mut => output.push_str("ptr_mut$<"),
+                    Mutability::Not => output.push_str("ptr_const$<"),
+                    Mutability::Mut => output.push_str("ptr_mut$<"),
                 }
             } else {
                 output.push('*');
                 match mutbl {
-                    hir::Mutability::Not => output.push_str("const "),
-                    hir::Mutability::Mut => output.push_str("mut "),
+                    Mutability::Not => output.push_str("const "),
+                    Mutability::Mut => output.push_str("mut "),
                 }
             }
 
@@ -131,8 +131,8 @@ fn push_debuginfo_type_name<'tcx>(
                 output.push_str(mutbl.prefix_str());
             } else if !is_slice_or_str {
                 match mutbl {
-                    hir::Mutability::Not => output.push_str("ref$<"),
-                    hir::Mutability::Mut => output.push_str("ref_mut$<"),
+                    Mutability::Not => output.push_str("ref$<"),
+                    Mutability::Mut => output.push_str("ref_mut$<"),
                 }
             }
 
@@ -345,14 +345,39 @@ fn push_debuginfo_type_name<'tcx>(
             // processing
             visited.remove(t);
         }
-        ty::Closure(def_id, ..) | ty::Generator(def_id, ..) => {
-            let key = tcx.def_key(def_id);
+        ty::Closure(def_id, substs) | ty::Generator(def_id, substs, ..) => {
+            // Name will be "{closure_env#0}<T1, T2, ...>", "{generator_env#0}<T1, T2, ...>", or
+            // "{async_fn_env#0}<T1, T2, ...>", etc.
+            let def_key = tcx.def_key(def_id);
+
             if qualified {
-                let parent_def_id = DefId { index: key.parent.unwrap(), ..def_id };
+                let parent_def_id = DefId { index: def_key.parent.unwrap(), ..def_id };
                 push_item_name(tcx, parent_def_id, true, output);
                 output.push_str("::");
             }
-            push_unqualified_item_name(tcx, def_id, key.disambiguated_data, output);
+
+            let mut label = String::with_capacity(20);
+            write!(&mut label, "{}_env", generator_kind_label(tcx.generator_kind(def_id))).unwrap();
+
+            push_disambiguated_special_name(
+                &label,
+                def_key.disambiguated_data.disambiguator,
+                cpp_like_debuginfo,
+                output,
+            );
+
+            // We also need to add the generic arguments of the async fn/generator or
+            // the enclosing function (for closures or async blocks), so that we end
+            // up with a unique name for every instantiation.
+
+            // Find the generics of the enclosing function, as defined in the source code.
+            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
+            // anything closure- or generator-specific.
+            let substs = substs.truncate_to(tcx, generics);
+            push_generic_params_internal(tcx, substs, output, visited);
         }
         // Type parameters from polymorphized functions.
         ty::Param(_) => {
@@ -509,6 +534,29 @@ pub fn push_item_name(tcx: TyCtxt<'_>, def_id: DefId, qualified: bool, output: &
     push_unqualified_item_name(tcx, def_id, def_key.disambiguated_data, output);
 }
 
+fn generator_kind_label(generator_kind: Option<GeneratorKind>) -> &'static str {
+    match generator_kind {
+        Some(GeneratorKind::Async(AsyncGeneratorKind::Block)) => "async_block",
+        Some(GeneratorKind::Async(AsyncGeneratorKind::Closure)) => "async_closure",
+        Some(GeneratorKind::Async(AsyncGeneratorKind::Fn)) => "async_fn",
+        Some(GeneratorKind::Gen) => "generator",
+        None => "closure",
+    }
+}
+
+fn push_disambiguated_special_name(
+    label: &str,
+    disambiguator: u32,
+    cpp_like_debuginfo: bool,
+    output: &mut String,
+) {
+    if cpp_like_debuginfo {
+        write!(output, "{}${}", label, disambiguator).unwrap();
+    } else {
+        write!(output, "{{{}#{}}}", label, disambiguator).unwrap();
+    }
+}
+
 fn push_unqualified_item_name(
     tcx: TyCtxt<'_>,
     def_id: DefId,
@@ -519,42 +567,32 @@ fn push_unqualified_item_name(
         DefPathData::CrateRoot => {
             output.push_str(tcx.crate_name(def_id.krate).as_str());
         }
-        DefPathData::ClosureExpr if tcx.generator_kind(def_id).is_some() => {
-            let key = match tcx.generator_kind(def_id).unwrap() {
-                hir::GeneratorKind::Async(hir::AsyncGeneratorKind::Block) => "async_block",
-                hir::GeneratorKind::Async(hir::AsyncGeneratorKind::Closure) => "async_closure",
-                hir::GeneratorKind::Async(hir::AsyncGeneratorKind::Fn) => "async_fn",
-                hir::GeneratorKind::Gen => "generator",
-            };
-            // Generators look like closures, but we want to treat them differently
-            // in the debug info.
-            if cpp_like_debuginfo(tcx) {
-                write!(output, "{}${}", key, disambiguated_data.disambiguator).unwrap();
-            } else {
-                write!(output, "{{{}#{}}}", key, disambiguated_data.disambiguator).unwrap();
-            }
+        DefPathData::ClosureExpr => {
+            let label = generator_kind_label(tcx.generator_kind(def_id));
+
+            push_disambiguated_special_name(
+                label,
+                disambiguated_data.disambiguator,
+                cpp_like_debuginfo(tcx),
+                output,
+            );
         }
         _ => match disambiguated_data.data.name() {
             DefPathDataName::Named(name) => {
                 output.push_str(name.as_str());
             }
             DefPathDataName::Anon { namespace } => {
-                if cpp_like_debuginfo(tcx) {
-                    write!(output, "{}${}", namespace, disambiguated_data.disambiguator).unwrap();
-                } else {
-                    write!(output, "{{{}#{}}}", namespace, disambiguated_data.disambiguator)
-                        .unwrap();
-                }
+                push_disambiguated_special_name(
+                    namespace.as_str(),
+                    disambiguated_data.disambiguator,
+                    cpp_like_debuginfo(tcx),
+                    output,
+                );
             }
         },
     };
 }
 
-// Pushes the generic parameters in the given `InternalSubsts` to the output string.
-// This ignores region parameters, since they can't reliably be
-// reconstructed for items from non-local crates. For local crates, this
-// would be possible but with inlining and LTO we have to use the least
-// common denominator - otherwise we would run into conflicts.
 fn push_generic_params_internal<'tcx>(
     tcx: TyCtxt<'tcx>,
     substs: SubstsRef<'tcx>,
diff --git a/src/test/codegen/async-fn-debug-msvc.rs b/src/test/codegen/async-fn-debug-msvc.rs
index bb0db9d3d8514..a90c85a54491d 100644
--- a/src/test/codegen/async-fn-debug-msvc.rs
+++ b/src/test/codegen/async-fn-debug-msvc.rs
@@ -17,7 +17,7 @@ async fn async_fn_test() {
 // FIXME: No way to reliably check the filename.
 
 // CHECK-DAG:  [[ASYNC_FN:!.*]] = !DINamespace(name: "async_fn_test"
-// CHECK-DAG:  [[GEN:!.*]] = !DICompositeType(tag: DW_TAG_union_type, name: "async_fn$0"
+// CHECK-DAG:  [[GEN:!.*]] = !DICompositeType(tag: DW_TAG_union_type, name: "async_fn_env$0"
 // CHECK:      {{!.*}} = !DIDerivedType(tag: DW_TAG_member, name: "variant0", scope: [[GEN]],
 // For brevity, we only check the struct name and members of the last variant.
 // CHECK-SAME: file: [[FILE:![0-9]*]], line: 11,
diff --git a/src/test/codegen/async-fn-debug.rs b/src/test/codegen/async-fn-debug.rs
index f456f7ffc0fba..8fbd2765fd771 100644
--- a/src/test/codegen/async-fn-debug.rs
+++ b/src/test/codegen/async-fn-debug.rs
@@ -17,7 +17,7 @@ async fn async_fn_test() {
 // FIXME: No way to reliably check the filename.
 
 // CHECK-DAG:  [[ASYNC_FN:!.*]] = !DINamespace(name: "async_fn_test"
-// CHECK-DAG:  [[GEN:!.*]] = !DICompositeType(tag: DW_TAG_structure_type, name: "{async_fn#0}", scope: [[ASYNC_FN]]
+// CHECK-DAG:  [[GEN:!.*]] = !DICompositeType(tag: DW_TAG_structure_type, name: "{async_fn_env#0}", scope: [[ASYNC_FN]]
 // CHECK:      [[VARIANT:!.*]] = !DICompositeType(tag: DW_TAG_variant_part, scope: [[ASYNC_FN]],
 // CHECK-NOT:  flags: DIFlagArtificial
 // CHECK-SAME: discriminator: [[DISC:![0-9]*]]
diff --git a/src/test/codegen/debug-vtable.rs b/src/test/codegen/debug-vtable.rs
index 1c8cc61f204dd..35fd275fd2897 100644
--- a/src/test/codegen/debug-vtable.rs
+++ b/src/test/codegen/debug-vtable.rs
@@ -1,25 +1,36 @@
-// compile-flags: -Cdebuginfo=2 -Copt-level=0 -Ccodegen-units=1
-// ignore-tidy-linelength
-
 // This test checks the debuginfo for the expected 3 vtables is generated for correct names and number
 // of entries.
 
-// NONMSVC-LABEL: !DIGlobalVariable(name: "<debug_vtable::Foo as debug_vtable::SomeTrait>::{vtable}"
-// MSVC-LABEL: !DIGlobalVariable(name: "impl$<debug_vtable::Foo, debug_vtable::SomeTrait>::vtable$"
+// Use the v0 symbol mangling scheme to codegen order independent of rustc version.
+// Unnamed items like shims are generated in lexicographical order of their symbol name and in the
+// legacy mangling scheme rustc version and generic parameters are both hashed into a single part
+// of the name, thus randomizing item order with respect to rustc version.
+
+// compile-flags: -Cdebuginfo=2 -Copt-level=0 -Csymbol-mangling-version=v0
+// ignore-tidy-linelength
+
+// NONMSVC: !DIGlobalVariable(name: "<debug_vtable::Foo as debug_vtable::SomeTrait>::{vtable}"
+// MSVC: !DIGlobalVariable(name: "impl$<debug_vtable::Foo, debug_vtable::SomeTrait>::vtable$"
 // NONMSVC: !DIDerivedType(tag: DW_TAG_pointer_type, name: "*const ()",
 // MSVC: !DIDerivedType(tag: DW_TAG_pointer_type, name: "ptr_const$<tuple$<> >",
 // CHECK: !DISubrange(count: 5
 
-// NONMSVC-LABEL: !DIGlobalVariable(name: "<debug_vtable::Foo as debug_vtable::SomeTraitWithGenerics<u64, i8>>::{vtable}"
-// MSVC-LABEL: !DIGlobalVariable(name: "impl$<debug_vtable::Foo, debug_vtable::SomeTraitWithGenerics<u64,i8> >::vtable$"
+// NONMSVC: !DIGlobalVariable(name: "<debug_vtable::Foo as debug_vtable::SomeTraitWithGenerics<u64, i8>>::{vtable}"
+// MSVC: !DIGlobalVariable(name: "impl$<debug_vtable::Foo, debug_vtable::SomeTraitWithGenerics<u64,i8> >::vtable$"
 // CHECK: !DISubrange(count: 4
 
-// NONMSVC-LABEL: !DIGlobalVariable(name: "<debug_vtable::Foo as _>::{vtable}"
-// MSVC-LABEL: !DIGlobalVariable(name: "impl$<debug_vtable::Foo, _>::vtable$"
+// NONMSVC: !DIGlobalVariable(name: "<debug_vtable::Foo as _>::{vtable}"
+// MSVC: !DIGlobalVariable(name: "impl$<debug_vtable::Foo, _>::vtable$"
 // CHECK: !DISubrange(count: 3
 
-// NONMSVC-LABEL: !DIGlobalVariable(name: "<debug_vtable::bar::{closure#0} as core::ops::function::FnOnce<(core::option::Option<&dyn core::ops::function::Fn<(), Output=()>>)>>::{vtable}"
-// MSVC-LABEL: !DIGlobalVariable(name: "impl$<debug_vtable::bar::closure$0, core::ops::function::FnOnce<tuple$<enum$<core::option::Option<ref$<dyn$<core::ops::function::Fn<tuple$<>,assoc$<Output,tuple$<> > > > > >, {{.*}}, {{.*}}, Some> > > >::vtable$"
+// NONMSVC: !DIGlobalVariable(name: "<debug_vtable::bar::{closure_env#0} as core::ops::function::FnOnce<(core::option::Option<&dyn core::ops::function::Fn<(), Output=()>>)>>::{vtable}"
+// MSVC: !DIGlobalVariable(name: "impl$<debug_vtable::bar::closure_env$0, core::ops::function::FnOnce<tuple$<enum$<core::option::Option<ref$<dyn$<core::ops::function::Fn<tuple$<>,assoc$<Output,tuple$<> > > > > >, {{.*}}, {{.*}}, Some> > > >::vtable$"
+
+// NONMSVC: !DIGlobalVariable(name: "<debug_vtable::generic_closure::{closure_env#0}<bool> as core::ops::function::FnOnce<()>>::{vtable}"
+// MSVC: !DIGlobalVariable(name: "impl$<debug_vtable::generic_closure::closure_env$0<bool>, core::ops::function::FnOnce<tuple$<> > >::vtable$
+
+// NONMSVC: !DIGlobalVariable(name: "<debug_vtable::generic_closure::{closure_env#0}<u32> as core::ops::function::FnOnce<()>>::{vtable}"
+// MSVC: !DIGlobalVariable(name: "impl$<debug_vtable::generic_closure::closure_env$0<u32>, core::ops::function::FnOnce<tuple$<> > >::vtable$
 
 #![crate_type = "lib"]
 
@@ -31,8 +42,12 @@ pub trait SomeTrait {
 }
 
 impl SomeTrait for Foo {
-    fn method1(&self) -> u32 { 1 }
-    fn method2(&self) -> u32 { 2 }
+    fn method1(&self) -> u32 {
+        1
+    }
+    fn method2(&self) -> u32 {
+        2
+    }
 }
 
 pub trait SomeTraitWithGenerics<T, U> {
@@ -40,7 +55,9 @@ pub trait SomeTraitWithGenerics<T, U> {
 }
 
 impl SomeTraitWithGenerics<u64, i8> for Foo {
-    fn method1(&self) -> (u64, i8) { (1, 2) }
+    fn method1(&self) -> (u64, i8) {
+        (1, 2)
+    }
 }
 
 pub fn foo(x: &Foo) -> (u32, (u64, i8), &dyn Send) {
@@ -55,3 +72,11 @@ pub fn foo(x: &Foo) -> (u32, (u64, i8), &dyn Send) {
 pub fn bar() -> Box<dyn FnOnce(Option<&dyn Fn()>)> {
     Box::new(|_x: Option<&dyn Fn()>| {})
 }
+
+fn generic_closure<T: 'static>(x: T) -> Box<dyn FnOnce() -> T> {
+    Box::new(move || x)
+}
+
+pub fn instantiate_generic_closures() -> (Box<dyn FnOnce() -> u32>, Box<dyn FnOnce() -> bool>) {
+    (generic_closure(1u32), generic_closure(false))
+}
diff --git a/src/test/codegen/debuginfo-generic-closure-env-names.rs b/src/test/codegen/debuginfo-generic-closure-env-names.rs
new file mode 100644
index 0000000000000..6e5ac95126130
--- /dev/null
+++ b/src/test/codegen/debuginfo-generic-closure-env-names.rs
@@ -0,0 +1,91 @@
+// This test checks that we get proper type names for closure environments and
+// async-fn environments in debuginfo, especially making sure that generic arguments
+// of the enclosing functions don't get lost.
+//
+// Unfortunately, the order that debuginfo gets emitted into LLVM IR becomes a bit hard
+// to predict once async fns are involved.
+//
+// Note that the test does not check async-fns when targeting MSVC because debuginfo for
+// those does not follow the enum-fallback encoding yet and thus is incomplete.
+
+// ignore-tidy-linelength
+
+// Use the v0 symbol mangling scheme to codegen order independent of rustc version.
+// Unnamed items like shims are generated in lexicographical order of their symbol name and in the
+// legacy mangling scheme rustc version and generic parameters are both hashed into a single part
+// of the name, thus randomizing item order with respect to rustc version.
+
+// compile-flags: -Cdebuginfo=2 --edition 2021 -Copt-level=0 -Csymbol-mangling-version=v0
+
+
+// CHECK: [[non_generic_closure_NAMESPACE:!.*]] = !DINamespace(name: "non_generic_closure"
+// CHECK: [[function_containing_closure_NAMESPACE:!.*]] = !DINamespace(name: "function_containing_closure"
+// CHECK: [[generic_async_function_NAMESPACE:!.*]] = !DINamespace(name: "generic_async_function"
+// CHECK: [[generic_async_block_NAMESPACE:!.*]] = !DINamespace(name: "generic_async_block"
+
+// non_generic_closure()
+// NONMSVC: !DICompositeType(tag: DW_TAG_structure_type, name: "{closure_env#0}", scope: [[non_generic_closure_NAMESPACE]]
+// MSVC: !DICompositeType(tag: DW_TAG_structure_type, name: "closure_env$0", scope: [[non_generic_closure_NAMESPACE]]
+
+// function_containing_closure<u32>()
+// NONMSVC: !DICompositeType(tag: DW_TAG_structure_type, name: "{closure_env#0}<u32>", scope: [[function_containing_closure_NAMESPACE]]
+// MSVC: !DICompositeType(tag: DW_TAG_structure_type, name: "closure_env$0<u32>", scope: [[function_containing_closure_NAMESPACE]]
+
+// generic_async_function<Foo>()
+// NONMSVC: !DICompositeType(tag: DW_TAG_structure_type, name: "{async_fn_env#0}<debuginfo_generic_closure_env_names::Foo>", scope: [[generic_async_function_NAMESPACE]]
+
+// generic_async_function<u32>()
+// NONMSVC: !DICompositeType(tag: DW_TAG_structure_type, name: "{async_fn_env#0}<u32>", scope: [[generic_async_function_NAMESPACE]]
+
+// generic_async_block<Foo>()
+// NONMSVC: !DICompositeType(tag: DW_TAG_structure_type, name: "{async_block_env#0}<debuginfo_generic_closure_env_names::Foo>", scope: [[generic_async_block_NAMESPACE]]
+
+// generic_async_block<u32>()
+// NONMSVC: !DICompositeType(tag: DW_TAG_structure_type, name: "{async_block_env#0}<u32>", scope: [[generic_async_block_NAMESPACE]]
+
+// function_containing_closure<Foo>()
+// NONMSVC: !DICompositeType(tag: DW_TAG_structure_type, name: "{closure_env#0}<debuginfo_generic_closure_env_names::Foo>", scope: [[function_containing_closure_NAMESPACE]]
+// MSVC: !DICompositeType(tag: DW_TAG_structure_type, name: "closure_env$0<debuginfo_generic_closure_env_names::Foo>", scope: [[function_containing_closure_NAMESPACE]]
+
+
+#![crate_type = "lib"]
+use std::future::Future;
+
+pub struct Foo;
+
+pub fn non_generic_closure(x: Foo) -> Box<dyn FnOnce() -> Foo> {
+    // This static only exists to trigger generating the namespace debuginfo for
+    // `function_containing_closure` at a predictable, early point, which makes
+    // writing the FileCheck tests above simpler.
+    static _X: u8 = 0;
+    return Box::new(move || x);
+}
+
+fn function_containing_closure<T: 'static>(x: T) -> impl FnOnce() -> T {
+    static _X: u8 = 0; // Same as above
+
+    return move || x;
+}
+
+async fn generic_async_function<T: 'static>(x: T) -> T {
+    static _X: u8 = 0; // Same as above
+    x
+}
+
+fn generic_async_block<T: 'static>(x: T) -> impl Future<Output=T> {
+    static _X: u8 = 0; // Same as above
+    async move {
+        x
+    }
+}
+
+pub fn instantiate_generics() {
+    let _closure_u32 = function_containing_closure(7u32);
+    let _closure_foo = function_containing_closure(Foo);
+
+    let _async_fn_u32 = generic_async_function(42u32);
+    let _async_fn_foo = generic_async_function(Foo);
+
+    let _async_block_u32 = generic_async_block(64u32);
+    let _async_block_foo = generic_async_block(Foo);
+}
diff --git a/src/test/codegen/generator-debug-msvc.rs b/src/test/codegen/generator-debug-msvc.rs
index 68d138f8df2f0..fb8b9e09fd24d 100644
--- a/src/test/codegen/generator-debug-msvc.rs
+++ b/src/test/codegen/generator-debug-msvc.rs
@@ -21,7 +21,7 @@ fn generator_test() -> impl Generator<Yield = i32, Return = ()> {
 // FIXME: No way to reliably check the filename.
 
 // CHECK-DAG:  [[GEN_FN:!.*]] = !DINamespace(name: "generator_test"
-// CHECK-DAG:  [[GEN:!.*]] = !DICompositeType(tag: DW_TAG_union_type, name: "generator$0"
+// CHECK-DAG:  [[GEN:!.*]] = !DICompositeType(tag: DW_TAG_union_type, name: "generator_env$0"
 // CHECK:      {{!.*}} = !DIDerivedType(tag: DW_TAG_member, name: "variant0", scope: [[GEN]],
 // For brevity, we only check the struct name and members of the last variant.
 // CHECK-SAME: file: [[FILE:![0-9]*]], line: 14,
diff --git a/src/test/codegen/generator-debug.rs b/src/test/codegen/generator-debug.rs
index ea324695c15d7..e777fe3af63e0 100644
--- a/src/test/codegen/generator-debug.rs
+++ b/src/test/codegen/generator-debug.rs
@@ -21,7 +21,7 @@ fn generator_test() -> impl Generator<Yield = i32, Return = ()> {
 // FIXME: No way to reliably check the filename.
 
 // CHECK-DAG:  [[GEN_FN:!.*]] = !DINamespace(name: "generator_test"
-// CHECK-DAG:  [[GEN:!.*]] = !DICompositeType(tag: DW_TAG_structure_type, name: "{generator#0}", scope: [[GEN_FN]]
+// CHECK-DAG:  [[GEN:!.*]] = !DICompositeType(tag: DW_TAG_structure_type, name: "{generator_env#0}", scope: [[GEN_FN]]
 // CHECK:      [[VARIANT:!.*]] = !DICompositeType(tag: DW_TAG_variant_part, scope: [[GEN_FN]],
 // CHECK-NOT:  flags: DIFlagArtificial
 // CHECK-SAME: discriminator: [[DISC:![0-9]*]]
diff --git a/src/test/debuginfo/captured-fields-1.rs b/src/test/debuginfo/captured-fields-1.rs
index 65f9e5f532279..afbf942d40471 100644
--- a/src/test/debuginfo/captured-fields-1.rs
+++ b/src/test/debuginfo/captured-fields-1.rs
@@ -4,44 +4,44 @@
 
 // gdb-command:run
 // gdb-command:print test
-// gdbr-check:$1 = captured_fields_1::main::{closure#0} {_ref__my_ref__my_field1: 0x[...]}
+// gdbr-check:$1 = captured_fields_1::main::{closure_env#0} {_ref__my_ref__my_field1: 0x[...]}
 // gdb-command:continue
 // gdb-command:print test
-// gdbr-check:$2 = captured_fields_1::main::{closure#1} {_ref__my_ref__my_field2: 0x[...]}
+// gdbr-check:$2 = captured_fields_1::main::{closure_env#1} {_ref__my_ref__my_field2: 0x[...]}
 // gdb-command:continue
 // gdb-command:print test
-// gdbr-check:$3 = captured_fields_1::main::{closure#2} {_ref__my_ref: 0x[...]}
+// gdbr-check:$3 = captured_fields_1::main::{closure_env#2} {_ref__my_ref: 0x[...]}
 // gdb-command:continue
 // gdb-command:print test
-// gdbr-check:$4 = captured_fields_1::main::{closure#3} {my_ref: 0x[...]}
+// gdbr-check:$4 = captured_fields_1::main::{closure_env#3} {my_ref: 0x[...]}
 // gdb-command:continue
 // gdb-command:print test
-// gdbr-check:$5 = captured_fields_1::main::{closure#4} {my_var__my_field2: 22}
+// gdbr-check:$5 = captured_fields_1::main::{closure_env#4} {my_var__my_field2: 22}
 // gdb-command:continue
 // gdb-command:print test
-// gdbr-check:$6 = captured_fields_1::main::{closure#5} {my_var: captured_fields_1::MyStruct {my_field1: 11, my_field2: 22}}
+// gdbr-check:$6 = captured_fields_1::main::{closure_env#5} {my_var: captured_fields_1::MyStruct {my_field1: 11, my_field2: 22}}
 // gdb-command:continue
 
 // === LLDB TESTS ==================================================================================
 
 // lldb-command:run
 // lldb-command:print test
-// lldbg-check:(captured_fields_1::main::{closure#0}) $0 = { _ref__my_ref__my_field1 = 0x[...] }
+// lldbg-check:(captured_fields_1::main::{closure_env#0}) $0 = { _ref__my_ref__my_field1 = 0x[...] }
 // lldb-command:continue
 // lldb-command:print test
-// lldbg-check:(captured_fields_1::main::{closure#1}) $1 = { _ref__my_ref__my_field2 = 0x[...] }
+// lldbg-check:(captured_fields_1::main::{closure_env#1}) $1 = { _ref__my_ref__my_field2 = 0x[...] }
 // lldb-command:continue
 // lldb-command:print test
-// lldbg-check:(captured_fields_1::main::{closure#2}) $2 = { _ref__my_ref = 0x[...] }
+// lldbg-check:(captured_fields_1::main::{closure_env#2}) $2 = { _ref__my_ref = 0x[...] }
 // lldb-command:continue
 // lldb-command:print test
-// lldbg-check:(captured_fields_1::main::{closure#3}) $3 = { my_ref = 0x[...] }
+// lldbg-check:(captured_fields_1::main::{closure_env#3}) $3 = { my_ref = 0x[...] }
 // lldb-command:continue
 // lldb-command:print test
-// lldbg-check:(captured_fields_1::main::{closure#4}) $4 = { my_var__my_field2 = 22 }
+// lldbg-check:(captured_fields_1::main::{closure_env#4}) $4 = { my_var__my_field2 = 22 }
 // lldb-command:continue
 // lldb-command:print test
-// lldbg-check:(captured_fields_1::main::{closure#5}) $5 = { my_var = { my_field1 = 11 my_field2 = 22 } }
+// lldbg-check:(captured_fields_1::main::{closure_env#5}) $5 = { my_var = { my_field1 = 11 my_field2 = 22 } }
 // lldb-command:continue
 
 #![feature(capture_disjoint_fields)]
@@ -53,10 +53,7 @@ struct MyStruct {
 }
 
 fn main() {
-    let mut my_var = MyStruct {
-        my_field1: 11,
-        my_field2: 22,
-    };
+    let mut my_var = MyStruct { my_field1: 11, my_field2: 22 };
     let my_ref = &mut my_var;
 
     let test = || {
diff --git a/src/test/debuginfo/function-names.rs b/src/test/debuginfo/function-names.rs
index ac9a02cce0481..73e34d4bb3211 100644
--- a/src/test/debuginfo/function-names.rs
+++ b/src/test/debuginfo/function-names.rs
@@ -27,9 +27,9 @@
 
 // Closure
 // gdb-command:info functions -q function_names::.*::{closure.*
-// gdb-check:[...]static fn function_names::generic_func::{closure#0}<i32>(*mut function_names::generic_func::{closure#0});
-// gdb-check:[...]static fn function_names::main::{closure#0}(*mut function_names::main::{closure#0});
-// gdb-check:[...]static fn function_names::{impl#2}::impl_function::{closure#0}<i32, i32>(*mut function_names::{impl#2}::impl_function::{closure#0});
+// gdb-check:[...]static fn function_names::generic_func::{closure#0}<i32>(*mut function_names::generic_func::{closure_env#0}<i32>);
+// gdb-check:[...]static fn function_names::main::{closure#0}(*mut function_names::main::{closure_env#0});
+// gdb-check:[...]static fn function_names::{impl#2}::impl_function::{closure#0}<i32, i32>(*mut function_names::{impl#2}::impl_function::{closure_env#0}<i32, i32>);
 
 // Generator
 // Generators don't seem to appear in GDB's symbol table.
@@ -86,9 +86,9 @@
 #![feature(adt_const_params, generators, generator_trait)]
 #![allow(incomplete_features)]
 
-use Mod1::TestTrait2;
 use std::ops::Generator;
 use std::pin::Pin;
+use Mod1::TestTrait2;
 
 fn main() {
     // Implementations
@@ -107,16 +107,19 @@ fn main() {
     let _ = generic_func(42i32);
 
     // Closure
-    let closure = || { TestStruct1 };
+    let closure = || TestStruct1;
     closure();
 
     // Generator
-    let mut generator = || { yield; return; };
+    let mut generator = || {
+        yield;
+        return;
+    };
     Pin::new(&mut generator).resume(());
 
     // Const generic functions
     const_generic_fn_bool::<false>();
-    const_generic_fn_non_int::<{()}>();
+    const_generic_fn_non_int::<{ () }>();
     const_generic_fn_signed_int::<-7>();
     const_generic_fn_unsigned_int::<14>();
 }
@@ -158,7 +161,7 @@ struct GenericStruct<T1, T2>(std::marker::PhantomData<(T1, T2)>);
 impl<T1, T2> GenericStruct<T1, T2> {
     pub fn impl_function() {
         // Closure in a generic implementation
-        let closure = || { TestStruct1 };
+        let closure = || TestStruct1;
         closure();
     }
 }
@@ -190,7 +193,7 @@ impl<T, const N: usize> TestTrait1 for GenericStruct<[T; N], f32> {
 // Generic function
 fn generic_func<T>(value: T) -> T {
     // Closure in a generic function
-    let closure = || { TestStruct1 };
+    let closure = || TestStruct1;
     closure();
 
     value
diff --git a/src/test/debuginfo/generator-objects.rs b/src/test/debuginfo/generator-objects.rs
index 9bf33a7bb8796..aee19736e7e1d 100644
--- a/src/test/debuginfo/generator-objects.rs
+++ b/src/test/debuginfo/generator-objects.rs
@@ -11,31 +11,31 @@
 
 // gdb-command:run
 // gdb-command:print b
-// gdb-check:$1 = generator_objects::main::{generator#0}::Unresumed{_ref__a: 0x[...]}
+// gdb-check:$1 = generator_objects::main::{generator_env#0}::Unresumed{_ref__a: 0x[...]}
 // gdb-command:continue
 // gdb-command:print b
-// gdb-check:$2 = generator_objects::main::{generator#0}::Suspend0{c: 6, d: 7, _ref__a: 0x[...]}
+// gdb-check:$2 = generator_objects::main::{generator_env#0}::Suspend0{c: 6, d: 7, _ref__a: 0x[...]}
 // gdb-command:continue
 // gdb-command:print b
-// gdb-check:$3 = generator_objects::main::{generator#0}::Suspend1{c: 7, d: 8, _ref__a: 0x[...]}
+// gdb-check:$3 = generator_objects::main::{generator_env#0}::Suspend1{c: 7, d: 8, _ref__a: 0x[...]}
 // gdb-command:continue
 // gdb-command:print b
-// gdb-check:$4 = generator_objects::main::{generator#0}::Returned{_ref__a: 0x[...]}
+// gdb-check:$4 = generator_objects::main::{generator_env#0}::Returned{_ref__a: 0x[...]}
 
 // === LLDB TESTS ==================================================================================
 
 // lldb-command:run
 // lldb-command:print b
-// lldbg-check:(generator_objects::main::{generator#0}) $0 =
+// lldbg-check:(generator_objects::main::{generator_env#0}) $0 =
 // lldb-command:continue
 // lldb-command:print b
-// lldbg-check:(generator_objects::main::{generator#0}) $1 =
+// lldbg-check:(generator_objects::main::{generator_env#0}) $1 =
 // lldb-command:continue
 // lldb-command:print b
-// lldbg-check:(generator_objects::main::{generator#0}) $2 =
+// lldbg-check:(generator_objects::main::{generator_env#0}) $2 =
 // lldb-command:continue
 // lldb-command:print b
-// lldbg-check:(generator_objects::main::{generator#0}) $3 =
+// lldbg-check:(generator_objects::main::{generator_env#0}) $3 =
 
 #![feature(omit_gdb_pretty_printer_section, generators, generator_trait)]
 #![omit_gdb_pretty_printer_section]
@@ -66,4 +66,6 @@ fn main() {
     _zzz(); // #break
 }
 
-fn _zzz() {()}
+fn _zzz() {
+    ()
+}
diff --git a/src/test/debuginfo/issue-57822.rs b/src/test/debuginfo/issue-57822.rs
index 1a26b0a3255b7..62e7eb13c2dc9 100644
--- a/src/test/debuginfo/issue-57822.rs
+++ b/src/test/debuginfo/issue-57822.rs
@@ -11,20 +11,20 @@
 // gdb-command:run
 
 // gdb-command:print g
-// gdb-check:$1 = issue_57822::main::{closure#1} {f: issue_57822::main::{closure#0} {x: 1}}
+// gdb-check:$1 = issue_57822::main::{closure_env#1} {f: issue_57822::main::{closure_env#0} {x: 1}}
 
 // gdb-command:print b
-// gdb-check:$2 = issue_57822::main::{generator#3}::Unresumed{a: issue_57822::main::{generator#2}::Unresumed{y: 2}}
+// gdb-check:$2 = issue_57822::main::{generator_env#3}::Unresumed{a: issue_57822::main::{generator_env#2}::Unresumed{y: 2}}
 
 // === LLDB TESTS ==================================================================================
 
 // lldb-command:run
 
 // lldb-command:print g
-// lldbg-check:(issue_57822::main::{closure#1}) $0 = { f = { x = 1 } }
+// lldbg-check:(issue_57822::main::{closure_env#1}) $0 = { f = { x = 1 } }
 
 // lldb-command:print b
-// lldbg-check:(issue_57822::main::{generator#3}) $1 =
+// lldbg-check:(issue_57822::main::{generator_env#3}) $1 =
 
 #![feature(omit_gdb_pretty_printer_section, generators, generator_trait)]
 #![omit_gdb_pretty_printer_section]
@@ -50,4 +50,6 @@ fn main() {
     zzz(); // #break
 }
 
-fn zzz() { () }
+fn zzz() {
+    ()
+}
diff --git a/src/test/debuginfo/type-names.rs b/src/test/debuginfo/type-names.rs
index 2c10360fc924e..c96921285626a 100644
--- a/src/test/debuginfo/type-names.rs
+++ b/src/test/debuginfo/type-names.rs
@@ -122,7 +122,6 @@
 // gdb-command:whatis has_associated_type_trait
 // gdb-check:type = &(dyn type_names::Trait3<u32, AssocType=isize> + core::marker::Send)
 
-
 // BARE FUNCTIONS
 // gdb-command:whatis rust_fn
 // gdb-check:type = (fn(core::option::Option<isize>, core::option::Option<&type_names::mod1::Struct2>), usize)
@@ -153,10 +152,10 @@
 
 // CLOSURES
 // gdb-command:whatis closure1
-// gdb-check:type = (type_names::main::{closure#0}, usize)
+// gdb-check:type = (type_names::main::{closure_env#0}, usize)
 
 // gdb-command:whatis closure2
-// gdb-check:type = (type_names::main::{closure#1}, usize)
+// gdb-check:type = (type_names::main::{closure_env#1}, usize)
 
 // FOREIGN TYPES
 // gdb-command:whatis foreign1
@@ -254,8 +253,8 @@
 
 // CLOSURES
 // cdb-command:dv /t closure*
-// cdb-check:struct tuple$<type_names::main::closure$1,usize> closure2 = [...]
-// cdb-check:struct tuple$<type_names::main::closure$0,usize> closure1 = [...]
+// cdb-check:struct tuple$<type_names::main::closure_env$1,usize> closure2 = [...]
+// cdb-check:struct tuple$<type_names::main::closure_env$0,usize> closure1 = [...]
 
 // FOREIGN TYPES
 // cdb-command:dv /t foreign*
@@ -279,7 +278,9 @@ enum Enum1 {
     Variant2(isize),
 }
 
-extern { type ForeignType1; }
+extern "C" {
+    type ForeignType1;
+}
 
 mod mod1 {
     pub use self::Enum2::{Variant1, Variant2};
@@ -300,7 +301,9 @@ mod mod1 {
         }
     }
 
-    extern { pub type ForeignType2; }
+    extern "C" {
+        pub type ForeignType2;
+    }
 }
 
 trait Trait1 {
@@ -311,7 +314,9 @@ trait Trait2<T1, T2> {
 }
 trait Trait3<T> {
     type AssocType;
-    fn dummy(&self) -> T { panic!() }
+    fn dummy(&self) -> T {
+        panic!()
+    }
 }
 
 impl Trait1 for isize {}
@@ -441,8 +446,8 @@ fn main() {
     let closure2 = (|x: i8, y: f32| (x as f32) + y, 0_usize);
 
     // Foreign Types
-    let foreign1 = unsafe{ 0 as *const ForeignType1 };
-    let foreign2 = unsafe{ 0 as *const mod1::ForeignType2 };
+    let foreign1 = unsafe { 0 as *const ForeignType1 };
+    let foreign2 = unsafe { 0 as *const mod1::ForeignType2 };
 
     zzz(); // #break
 }
diff --git a/src/test/debuginfo/var-captured-in-nested-closure.rs b/src/test/debuginfo/var-captured-in-nested-closure.rs
index d811915c38767..537c0b50b8b64 100644
--- a/src/test/debuginfo/var-captured-in-nested-closure.rs
+++ b/src/test/debuginfo/var-captured-in-nested-closure.rs
@@ -108,7 +108,7 @@
 // cdb-command: dx closure_local
 // cdb-check:closure_local    : 8 [Type: [...]]
 // cdb-command: dx nested_closure
-// cdb-check:nested_closure   [Type: var_captured_in_nested_closure::main::closure$0::closure$0]
+// cdb-check:nested_closure   [Type: var_captured_in_nested_closure::main::closure$0::closure_env$0]
 
 // cdb-command: g