[vm] Implement constant Maps in the VM

This CL changes the frontend to emit map and set constants which are
then processed by the constant reader in the VM.

This CL also introduces support for sending the const maps and sets
in messages between isolates and saving it in snapshots.

TEST=tests/language/const/map_test.dart (et al, for lookups)
TEST=tests/lib/isolate/message3_test.dart (et al, for isolate messages)
TEST=tools/test.py -c dartkp (for consts from clustered snapshot)
TEST=tools/test.py -n app_jitk-linux-debug-x64 (for consts from app
     jit snapshots)
TEST=Building the SDK which uses const Maps in clustered snapshots.

Closes: #45908

Change-Id: I1f8150a8aba8298c4e64d2571dd147743526135a
Cq-Include-Trybots: luci.dart.try:analyzer-nnbd-linux-release-try,app-kernel-linux-debug-x64-try,dart-sdk-linux-try,front-end-nnbd-linux-release-x64-try,pkg-linux-debug-try,vm-canary-linux-debug-try,vm-kernel-asan-linux-release-x64-try,vm-kernel-checked-linux-release-x64-try,vm-kernel-linux-debug-x64c-try,vm-kernel-linux-debug-x64-try,vm-kernel-linux-debug-simarm64c-try,vm-kernel-nnbd-linux-release-simarm-try,vm-kernel-optcounter-threshold-linux-release-x64-try,vm-kernel-precomp-android-release-arm_x64-try,vm-kernel-precomp-linux-debug-x64-try,vm-kernel-precomp-linux-debug-x64c-try,vm-kernel-reload-linux-debug-x64-try,vm-kernel-reload-rollback-linux-debug-x64-try,vm-precomp-ffi-qemu-linux-release-arm-try,vm-kernel-precomp-linux-debug-simarm_x64-try,vm-kernel-precomp-linux-debug-x64-try,vm-kernel-precomp-tsan-linux-release-x64-try,vm-kernel-tsan-linux-release-x64-try
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/203765
Reviewed-by: Martin Kustermann <kustermann@google.com>

pkg/front_end/lib/src/fasta/source/source_loader.dart

@@ -1589,10 +1589,6 @@ abstract class Map<K, V> extends Iterable {
   void operator []=(K key, V value) {}
 }
 
-abstract class _ImmutableMap<K, V> implements Map<K, V> {
-  dynamic _kvPairs;
-}
-
 abstract class pragma {
   String name;
   Object options;

pkg/front_end/testcases/agnostic/map.dart.strong.expect

@@ -4,14 +4,13 @@ import "dart:core" as core;
 
 static const field core::List<core::int> a = #C1;
 static const field core::List<core::int?> b = #C2;
-static const field core::Map<core::List<core::int?>, core::int> c = #C6;
+static const field core::Map<core::List<core::int?>, core::int> c = #C5;
 static method main() → dynamic {}
 
 constants  {
   #C1 = <core::int>[]
   #C2 = <core::int?>[]
   #C3 = 0
   #C4 = 1
-  #C5 = <dynamic>[#C1, #C3, #C2, #C4]
-  #C6 = core::_ImmutableMap<core::List<core::int?>, core::int> {_kvPairs:#C5}
+  #C5 = <core::List<core::int?>, core::int>{#C1:#C3, #C2:#C4)
 }

pkg/front_end/testcases/agnostic/map.dart.strong.transformed.expect

@@ -4,14 +4,13 @@ import "dart:core" as core;
 
 static const field core::List<core::int> a = #C1;
 static const field core::List<core::int?> b = #C2;
-static const field core::Map<core::List<core::int?>, core::int> c = #C6;
+static const field core::Map<core::List<core::int?>, core::int> c = #C5;
 static method main() → dynamic {}
 
 constants  {
   #C1 = <core::int>[]
   #C2 = <core::int?>[]
   #C3 = 0
   #C4 = 1
-  #C5 = <dynamic>[#C1, #C3, #C2, #C4]
-  #C6 = core::_ImmutableMap<core::List<core::int?>, core::int> {_kvPairs:#C5}
+  #C5 = <core::List<core::int?>, core::int>{#C1:#C3, #C2:#C4)
 }

pkg/front_end/testcases/agnostic/map.dart.weak.expect

@@ -4,14 +4,13 @@ import "dart:core" as core;
 
 static const field core::List<core::int> a = #C1;
 static const field core::List<core::int?> b = #C2;
-static const field core::Map<core::List<core::int?>, core::int> c = #C6;
+static const field core::Map<core::List<core::int?>, core::int> c = #C5;
 static method main() → dynamic {}
 
 constants  {
   #C1 = <core::int*>[]
   #C2 = <core::int?>[]
   #C3 = 0
   #C4 = 1
-  #C5 = <dynamic>[#C1, #C3, #C2, #C4]
-  #C6 = core::_ImmutableMap<core::List<core::int?>*, core::int*> {_kvPairs:#C5}
+  #C5 = <core::List<core::int?>*, core::int*>{#C1:#C3, #C2:#C4)
 }

pkg/front_end/testcases/agnostic/map.dart.weak.outline.expect

@@ -12,5 +12,5 @@ static method main() → dynamic
 Extra constant evaluation status:
 Evaluated: ListLiteral @ org-dartlang-testcase:///map.dart:5:16 -> ListConstant(const <int*>[])
 Evaluated: ListLiteral @ org-dartlang-testcase:///map.dart:6:17 -> ListConstant(const <int?>[])
-Evaluated: MapLiteral @ org-dartlang-testcase:///map.dart:7:11 -> InstanceConstant(const _ImmutableMap<List<int?>*, int*>{_ImmutableMap._kvPairs: const <dynamic>[const <int*>[], 0, const <int?>[], 1]})
+Evaluated: MapLiteral @ org-dartlang-testcase:///map.dart:7:11 -> MapConstant(const <List<int?>*, int*>{const <int*>[]: 0, const <int?>[]: 1})
 Extra constant evaluation: evaluated: 3, effectively constant: 3

pkg/front_end/testcases/agnostic/map.dart.weak.transformed.expect

@@ -4,14 +4,13 @@ import "dart:core" as core;
 
 static const field core::List<core::int> a = #C1;
 static const field core::List<core::int?> b = #C2;
-static const field core::Map<core::List<core::int?>, core::int> c = #C6;
+static const field core::Map<core::List<core::int?>, core::int> c = #C5;
 static method main() → dynamic {}
 
 constants  {
   #C1 = <core::int*>[]
   #C2 = <core::int?>[]
   #C3 = 0
   #C4 = 1
-  #C5 = <dynamic>[#C1, #C3, #C2, #C4]
-  #C6 = core::_ImmutableMap<core::List<core::int?>*, core::int*> {_kvPairs:#C5}
+  #C5 = <core::List<core::int?>*, core::int*>{#C1:#C3, #C2:#C4)
 }

pkg/front_end/testcases/agnostic/set.dart.strong.expect

@@ -4,14 +4,11 @@ import "dart:core" as core;
 
 static const field core::List<core::int> a = #C1;
 static const field core::List<core::int?> b = #C2;
-static const field core::Set<core::List<core::int?>> c = #C6;
+static const field core::Set<core::List<core::int?>> c = #C3;
 static method main() → dynamic {}
 
 constants  {
   #C1 = <core::int>[]
   #C2 = <core::int?>[]
-  #C3 = null
-  #C4 = <dynamic>[#C1, #C3, #C2, #C3]
-  #C5 = core::_ImmutableMap<core::List<core::int?>, Null> {_kvPairs:#C4}
-  #C6 = col::_UnmodifiableSet<core::List<core::int?>> {_map:#C5}
+  #C3 = <core::List<core::int?>>{#C1, #C2}
 }

pkg/front_end/testcases/agnostic/set.dart.strong.transformed.expect

@@ -4,14 +4,11 @@ import "dart:core" as core;
 
 static const field core::List<core::int> a = #C1;
 static const field core::List<core::int?> b = #C2;
-static const field core::Set<core::List<core::int?>> c = #C6;
+static const field core::Set<core::List<core::int?>> c = #C3;
 static method main() → dynamic {}
 
 constants  {
   #C1 = <core::int>[]
   #C2 = <core::int?>[]
-  #C3 = null
-  #C4 = <dynamic>[#C1, #C3, #C2, #C3]
-  #C5 = core::_ImmutableMap<core::List<core::int?>, Null> {_kvPairs:#C4}
-  #C6 = col::_UnmodifiableSet<core::List<core::int?>> {_map:#C5}
+  #C3 = <core::List<core::int?>>{#C1, #C2}
 }

pkg/front_end/testcases/agnostic/set.dart.weak.expect

@@ -4,14 +4,11 @@ import "dart:core" as core;
 
 static const field core::List<core::int> a = #C1;
 static const field core::List<core::int?> b = #C2;
-static const field core::Set<core::List<core::int?>> c = #C6;
+static const field core::Set<core::List<core::int?>> c = #C3;
 static method main() → dynamic {}
 
 constants  {
   #C1 = <core::int*>[]
   #C2 = <core::int?>[]
-  #C3 = null
-  #C4 = <dynamic>[#C1, #C3, #C2, #C3]
-  #C5 = core::_ImmutableMap<core::List<core::int?>*, Null> {_kvPairs:#C4}
-  #C6 = col::_UnmodifiableSet<core::List<core::int?>*> {_map:#C5}
+  #C3 = <core::List<core::int?>*>{#C1, #C2}
 }

pkg/front_end/testcases/agnostic/set.dart.weak.outline.expect

@@ -12,5 +12,5 @@ static method main() → dynamic
 Extra constant evaluation status:
 Evaluated: ListLiteral @ org-dartlang-testcase:///set.dart:5:16 -> ListConstant(const <int*>[])
 Evaluated: ListLiteral @ org-dartlang-testcase:///set.dart:6:17 -> ListConstant(const <int?>[])
-Evaluated: SetLiteral @ org-dartlang-testcase:///set.dart:7:11 -> InstanceConstant(const _UnmodifiableSet<List<int?>*>{_UnmodifiableSet._map: const _ImmutableMap<List<int?>*, Null>{_ImmutableMap._kvPairs: const <dynamic>[const <int*>[], null, const <int?>[], null]}})
+Evaluated: SetLiteral @ org-dartlang-testcase:///set.dart:7:11 -> SetConstant(const <List<int?>*>{const <int*>[], const <int?>[]})
 Extra constant evaluation: evaluated: 3, effectively constant: 3

pkg/front_end/testcases/agnostic/set.dart.weak.transformed.expect

@@ -4,14 +4,11 @@ import "dart:core" as core;
 
 static const field core::List<core::int> a = #C1;
 static const field core::List<core::int?> b = #C2;
-static const field core::Set<core::List<core::int?>> c = #C6;
+static const field core::Set<core::List<core::int?>> c = #C3;
 static method main() → dynamic {}
 
 constants  {
   #C1 = <core::int*>[]
   #C2 = <core::int?>[]
-  #C3 = null
-  #C4 = <dynamic>[#C1, #C3, #C2, #C3]
-  #C5 = core::_ImmutableMap<core::List<core::int?>*, Null> {_kvPairs:#C4}
-  #C6 = col::_UnmodifiableSet<core::List<core::int?>*> {_map:#C5}
+  #C3 = <core::List<core::int?>*>{#C1, #C2}
 }

pkg/front_end/testcases/const_functions/const_functions_map.dart.strong.expect

@@ -8,7 +8,7 @@ import "package:expect/expect.dart";
 static const field core::Object? var1 = #C1;
 static const field core::Object? var2 = #C2;
 static const field core::Object? var3 = #C3;
-static const field core::Map<core::String, core::int> map = #C10;
+static const field core::Map<core::String, core::int> map = #C9;
 static const field core::Object? var4 = #C2;
 static const field core::Object? var5 = #C6;
 static const field core::Object? var6 = #C8;
@@ -17,7 +17,7 @@ static method fn(core::Map<core::Object, core::Object> map, core::Object key) 
   return map.{core::Map::[]}(key){(core::Object?) → core::Object?};
 }
 static method fn2() → core::int? {
-  return (#C13).{core::Map::[]}("key"){(core::Object?) → core::int?};
+  return (#C11).{core::Map::[]}("key"){(core::Object?) → core::int?};
 }
 static method main() → void {
   exp::Expect::equals(#C1, "val");
@@ -38,9 +38,7 @@ constants  {
   #C6 = 3
   #C7 = "key3"
   #C8 = 4
-  #C9 = <dynamic>[#C4, #C2, #C5, #C6, #C7, #C8]
-  #C10 = core::_ImmutableMap<core::String, core::int> {_kvPairs:#C9}
-  #C11 = "key"
-  #C12 = <dynamic>[#C11, #C2]
-  #C13 = core::_ImmutableMap<core::String, core::int> {_kvPairs:#C12}
+  #C9 = <core::String, core::int>{#C4:#C2, #C5:#C6, #C7:#C8)
+  #C10 = "key"
+  #C11 = <core::String, core::int>{#C10:#C2)
 }

pkg/front_end/testcases/const_functions/const_functions_map.dart.strong.transformed.expect

@@ -8,7 +8,7 @@ import "package:expect/expect.dart";
 static const field core::Object? var1 = #C1;
 static const field core::Object? var2 = #C2;
 static const field core::Object? var3 = #C3;
-static const field core::Map<core::String, core::int> map = #C10;
+static const field core::Map<core::String, core::int> map = #C9;
 static const field core::Object? var4 = #C2;
 static const field core::Object? var5 = #C6;
 static const field core::Object? var6 = #C8;
@@ -17,7 +17,7 @@ static method fn(core::Map<core::Object, core::Object> map, core::Object key) 
   return map.{core::Map::[]}(key){(core::Object?) → core::Object?};
 }
 static method fn2() → core::int? {
-  return (#C13).{core::Map::[]}("key"){(core::Object?) → core::int?};
+  return (#C11).{core::Map::[]}("key"){(core::Object?) → core::int?};
 }
 static method main() → void {
   exp::Expect::equals(#C1, "val");
@@ -38,9 +38,7 @@ constants  {
   #C6 = 3
   #C7 = "key3"
   #C8 = 4
-  #C9 = <dynamic>[#C4, #C2, #C5, #C6, #C7, #C8]
-  #C10 = core::_ImmutableMap<core::String, core::int> {_kvPairs:#C9}
-  #C11 = "key"
-  #C12 = <dynamic>[#C11, #C2]
-  #C13 = core::_ImmutableMap<core::String, core::int> {_kvPairs:#C12}
+  #C9 = <core::String, core::int>{#C4:#C2, #C5:#C6, #C7:#C8)
+  #C10 = "key"
+  #C11 = <core::String, core::int>{#C10:#C2)
 }

pkg/front_end/testcases/const_functions/const_functions_map.dart.weak.expect

@@ -8,7 +8,7 @@ import "package:expect/expect.dart";
 static const field core::Object? var1 = #C1;
 static const field core::Object? var2 = #C2;
 static const field core::Object? var3 = #C3;
-static const field core::Map<core::String, core::int> map = #C10;
+static const field core::Map<core::String, core::int> map = #C9;
 static const field core::Object? var4 = #C2;
 static const field core::Object? var5 = #C6;
 static const field core::Object? var6 = #C8;
@@ -17,7 +17,7 @@ static method fn(core::Map<core::Object, core::Object> map, core::Object key) 
   return map.{core::Map::[]}(key){(core::Object?) → core::Object?};
 }
 static method fn2() → core::int? {
-  return (#C13).{core::Map::[]}("key"){(core::Object?) → core::int?};
+  return (#C11).{core::Map::[]}("key"){(core::Object?) → core::int?};
 }
 static method main() → void {
   exp::Expect::equals(#C1, "val");
@@ -38,9 +38,7 @@ constants  {
   #C6 = 3
   #C7 = "key3"
   #C8 = 4
-  #C9 = <dynamic>[#C4, #C2, #C5, #C6, #C7, #C8]
-  #C10 = core::_ImmutableMap<core::String*, core::int*> {_kvPairs:#C9}
-  #C11 = "key"
-  #C12 = <dynamic>[#C11, #C2]
-  #C13 = core::_ImmutableMap<core::String*, core::int*> {_kvPairs:#C12}
+  #C9 = <core::String*, core::int*>{#C4:#C2, #C5:#C6, #C7:#C8)
+  #C10 = "key"
+  #C11 = <core::String*, core::int*>{#C10:#C2)
 }

pkg/front_end/testcases/const_functions/const_functions_map.dart.weak.outline.expect

@@ -21,11 +21,11 @@ static method main() → void
 
 
 Extra constant evaluation status:
-Evaluated: MapLiteral @ org-dartlang-testcase:///const_functions_map.dart:9:17 -> InstanceConstant(const _ImmutableMap<Object*, Object*>{_ImmutableMap._kvPairs: const <dynamic>["key", "val"]})
-Evaluated: MapLiteral @ org-dartlang-testcase:///const_functions_map.dart:11:17 -> InstanceConstant(const _ImmutableMap<Object*, Object*>{_ImmutableMap._kvPairs: const <dynamic>["key", 2]})
-Evaluated: MapLiteral @ org-dartlang-testcase:///const_functions_map.dart:13:17 -> InstanceConstant(const _ImmutableMap<Object*, Object*>{_ImmutableMap._kvPairs: const <dynamic>["key", 2]})
-Evaluated: MapLiteral @ org-dartlang-testcase:///const_functions_map.dart:15:13 -> InstanceConstant(const _ImmutableMap<String*, int*>{_ImmutableMap._kvPairs: const <dynamic>["key1", 2, "key2", 3, "key3", 4]})
-Evaluated: StaticGet @ org-dartlang-testcase:///const_functions_map.dart:16:17 -> InstanceConstant(const _ImmutableMap<String*, int*>{_ImmutableMap._kvPairs: const <dynamic>["key1", 2, "key2", 3, "key3", 4]})
-Evaluated: StaticGet @ org-dartlang-testcase:///const_functions_map.dart:17:17 -> InstanceConstant(const _ImmutableMap<String*, int*>{_ImmutableMap._kvPairs: const <dynamic>["key1", 2, "key2", 3, "key3", 4]})
-Evaluated: StaticGet @ org-dartlang-testcase:///const_functions_map.dart:18:17 -> InstanceConstant(const _ImmutableMap<String*, int*>{_ImmutableMap._kvPairs: const <dynamic>["key1", 2, "key2", 3, "key3", 4]})
+Evaluated: MapLiteral @ org-dartlang-testcase:///const_functions_map.dart:9:17 -> MapConstant(const <Object*, Object*>{"key": "val"})
+Evaluated: MapLiteral @ org-dartlang-testcase:///const_functions_map.dart:11:17 -> MapConstant(const <Object*, Object*>{"key": 2})
+Evaluated: MapLiteral @ org-dartlang-testcase:///const_functions_map.dart:13:17 -> MapConstant(const <Object*, Object*>{"key": 2})
+Evaluated: MapLiteral @ org-dartlang-testcase:///const_functions_map.dart:15:13 -> MapConstant(const <String*, int*>{"key1": 2, "key2": 3, "key3": 4})
+Evaluated: StaticGet @ org-dartlang-testcase:///const_functions_map.dart:16:17 -> MapConstant(const <String*, int*>{"key1": 2, "key2": 3, "key3": 4})
+Evaluated: StaticGet @ org-dartlang-testcase:///const_functions_map.dart:17:17 -> MapConstant(const <String*, int*>{"key1": 2, "key2": 3, "key3": 4})
+Evaluated: StaticGet @ org-dartlang-testcase:///const_functions_map.dart:18:17 -> MapConstant(const <String*, int*>{"key1": 2, "key2": 3, "key3": 4})
 Extra constant evaluation: evaluated: 14, effectively constant: 7

pkg/front_end/testcases/const_functions/const_functions_map.dart.weak.transformed.expect

@@ -8,7 +8,7 @@ import "package:expect/expect.dart";
 static const field core::Object? var1 = #C1;
 static const field core::Object? var2 = #C2;
 static const field core::Object? var3 = #C3;
-static const field core::Map<core::String, core::int> map = #C10;
+static const field core::Map<core::String, core::int> map = #C9;
 static const field core::Object? var4 = #C2;
 static const field core::Object? var5 = #C6;
 static const field core::Object? var6 = #C8;
@@ -17,7 +17,7 @@ static method fn(core::Map<core::Object, core::Object> map, core::Object key) 
   return map.{core::Map::[]}(key){(core::Object?) → core::Object?};
 }
 static method fn2() → core::int? {
-  return (#C13).{core::Map::[]}("key"){(core::Object?) → core::int?};
+  return (#C11).{core::Map::[]}("key"){(core::Object?) → core::int?};
 }
 static method main() → void {
   exp::Expect::equals(#C1, "val");
@@ -38,9 +38,7 @@ constants  {
   #C6 = 3
   #C7 = "key3"
   #C8 = 4
-  #C9 = <dynamic>[#C4, #C2, #C5, #C6, #C7, #C8]
-  #C10 = core::_ImmutableMap<core::String*, core::int*> {_kvPairs:#C9}
-  #C11 = "key"
-  #C12 = <dynamic>[#C11, #C2]
-  #C13 = core::_ImmutableMap<core::String*, core::int*> {_kvPairs:#C12}
+  #C9 = <core::String*, core::int*>{#C4:#C2, #C5:#C6, #C7:#C8)
+  #C10 = "key"
+  #C11 = <core::String*, core::int*>{#C10:#C2)
 }

pkg/front_end/testcases/constructor_tearoffs/issue46719.dart.strong.expect

@@ -23,35 +23,34 @@ extension FunctionApplier on core::Function {
 static method m<X extends core::Object? = dynamic>(self::m::X% x) → core::List<self::m::X%>
   return <self::m::X%>[x];
 static method FunctionApplier|applyAndPrint(lowered final core::Function #this, core::List<core::Object?> positionalArguments) → void
-  return core::print(core::Function::apply(#this, positionalArguments, #C2));
+  return core::print(core::Function::apply(#this, positionalArguments, #C1));
 static method FunctionApplier|get#applyAndPrint(lowered final core::Function #this) → (core::List<core::Object?>) → void
   return (core::List<core::Object?> positionalArguments) → void => self::FunctionApplier|applyAndPrint(#this, positionalArguments);
 static method test() → dynamic {
-  (#C4).{core::Object::toString}(){() → core::String};
+  (#C3).{core::Object::toString}(){() → core::String};
 }
 static method main() → void {
   self::A<dynamic> a = new self::A::•<dynamic>();
   self::FunctionApplier|applyAndPrint(a.{self::A::m}{<X extends core::Object? = dynamic>(X%) → core::List<X%>}<core::int>, <core::Object?>[2]);
   self::FunctionApplier|applyAndPrint(a.{self::A::m}{<X extends core::Object? = dynamic>(X%) → core::List<X%>}<core::String>, <core::Object?>["three"]);
-  self::FunctionApplier|applyAndPrint(#C6, <core::Object?>[2]);
-  self::FunctionApplier|applyAndPrint(#C7, <core::Object?>["three"]);
-  self::FunctionApplier|applyAndPrint(#C9, <core::Object?>[2]);
-  self::FunctionApplier|applyAndPrint(#C10, <core::Object?>["three"]);
-  self::FunctionApplier|applyAndPrint(#C6, <core::Object?>[2]);
-  self::FunctionApplier|applyAndPrint(#C7, <core::Object?>["three"]);
+  self::FunctionApplier|applyAndPrint(#C5, <core::Object?>[2]);
+  self::FunctionApplier|applyAndPrint(#C6, <core::Object?>["three"]);
+  self::FunctionApplier|applyAndPrint(#C8, <core::Object?>[2]);
+  self::FunctionApplier|applyAndPrint(#C9, <core::Object?>["three"]);
+  self::FunctionApplier|applyAndPrint(#C5, <core::Object?>[2]);
+  self::FunctionApplier|applyAndPrint(#C6, <core::Object?>["three"]);
+  (#C2).{core::Object::toString}(){() → core::String};
   (#C3).{core::Object::toString}(){() → core::String};
-  (#C4).{core::Object::toString}(){() → core::String};
 }
 
 constants  {
-  #C1 = <dynamic>[]
-  #C2 = core::_ImmutableMap<core::Symbol, dynamic> {_kvPairs:#C1}
-  #C3 = constructor-tearoff self::A::named
-  #C4 = instantiation self::A::named <core::int>
-  #C5 = static-tearoff self::A::n
-  #C6 = instantiation self::A::n <core::int>
-  #C7 = instantiation self::A::n <core::String>
-  #C8 = static-tearoff self::m
-  #C9 = instantiation self::m <core::int>
-  #C10 = instantiation self::m <core::String>
+  #C1 = <core::Symbol, dynamic>{)
+  #C2 = constructor-tearoff self::A::named
+  #C3 = instantiation self::A::named <core::int>
+  #C4 = static-tearoff self::A::n
+  #C5 = instantiation self::A::n <core::int>
+  #C6 = instantiation self::A::n <core::String>
+  #C7 = static-tearoff self::m
+  #C8 = instantiation self::m <core::int>
+  #C9 = instantiation self::m <core::String>
 }