diff --git a/pkg/dart2wasm/lib/constants.dart b/pkg/dart2wasm/lib/constants.dart
index e83a277c7d4..b3b742bee45 100644
--- a/pkg/dart2wasm/lib/constants.dart
+++ b/pkg/dart2wasm/lib/constants.dart
@@ -164,7 +164,7 @@ typedef ConstantCodeGeneratorLazy = bool Function(
 class Constants {
   final Translator translator;
   final Map<Constant, ConstantInfo> constantInfo = {};
-  w.DataSegmentBuilder? int32Segment;
+  w.DataSegmentBuilder? byteSegment;
   late final ClassInfo typeInfo = translator.classInfo[translator.typeClass]!;
 
   late final _constantAccessor = _ConstantAccessor(translator);
@@ -888,25 +888,40 @@ class ConstantCreator extends ConstantVisitor<ConstantInfo?>
         // This can be a little bit larger than individual array stores, but the
         // data section will compress better, so for app.wasm.gz it'a a win and
         // will cause much faster validation & faster initialization.
-        if (arrayType.elementType.type == w.NumType.i32) {
+        final fieldType = arrayType.elementType.type;
+        final isI32 = fieldType == w.NumType.i32;
+        final isI16 = fieldType == w.PackedType.i16;
+        if (isI32 || isI16) {
           // Initialize array contents from passive data segment.
           final w.DataSegmentBuilder segment =
-              constants.int32Segment ??= b.moduleBuilder.dataSegments.define();
-
+              constants.byteSegment ??= b.moduleBuilder.dataSegments.define();
           final field = translator.wasmI32Value.fieldReference;
 
-          final list = Uint32List(elements.length);
-          for (int i = 0; i < list.length; ++i) {
-            // The constant is a `const WasmI32 {WasmI32._value: <XXX>}`
-            final constant = elements[i] as InstanceConstant;
-            assert(constant.classNode == translator.wasmI32Class);
-            list[i] = (constant.fieldValues[field] as IntConstant).value;
+          Uint8List bytes;
+          if (isI16) {
+            final list = Uint16List(elements.length);
+            for (int i = 0; i < list.length; ++i) {
+              // The constant is a `const WasmI32 {WasmI32._value: <XXX>}`
+              final constant = elements[i] as InstanceConstant;
+              assert(constant.classNode == translator.wasmI32Class);
+              list[i] = (constant.fieldValues[field] as IntConstant).value;
+            }
+            bytes = list.buffer.asUint8List();
+          } else {
+            assert(isI32);
+            final list = Uint32List(elements.length);
+            for (int i = 0; i < list.length; ++i) {
+              // The constant is a `const WasmI32 {WasmI32._value: <XXX>}`
+              final constant = elements[i] as InstanceConstant;
+              assert(constant.classNode == translator.wasmI32Class);
+              list[i] = (constant.fieldValues[field] as IntConstant).value;
+            }
+            bytes = list.buffer.asUint8List();
           }
-          final offset = segment.length;
-          segment.append(list.buffer.asUint8List());
-          b.i32_const(offset);
+          b.i32_const(segment.length);
           b.i32_const(elements.length);
           b.array_new_data(arrayType, segment);
+          segment.append(bytes);
           return;
         }
 
diff --git a/pkg/dart2wasm/lib/kernel_nodes.dart b/pkg/dart2wasm/lib/kernel_nodes.dart
index a568206bb46..6bd8c6e76a4 100644
--- a/pkg/dart2wasm/lib/kernel_nodes.dart
+++ b/pkg/dart2wasm/lib/kernel_nodes.dart
@@ -127,8 +127,10 @@ mixin KernelNodes {
       index.getField("dart:core", "_ModuleRtt", "typeRowDisplacementOffsets");
   late final Field moduleRttDisplacementTable =
       index.getField("dart:core", "_ModuleRtt", "typeRowDisplacementTable");
-  late final Field moduleRttSubstTable = index.getField(
+  late final Field moduleRttDisplacementSubstTable = index.getField(
       "dart:core", "_ModuleRtt", "typeRowDisplacementSubstTable");
+  late final Field moduleRttSubstTable =
+      index.getField("dart:core", "_ModuleRtt", "canonicalSubstitutionTable");
   late final Field moduleRttTypeNames =
       index.getField("dart:core", "_ModuleRtt", "typeNames");
   late final Procedure registerModuleRtt =
@@ -438,6 +440,8 @@ mixin KernelNodes {
       index.getTopLevelField('dart:_internal', 'i8ConstImmutableArray');
   late final Field i32ConstArrayCache =
       index.getTopLevelField('dart:_internal', 'i32ConstArray');
+  late final Field i16ConstArrayCache =
+      index.getTopLevelField('dart:_internal', 'i16ConstArray');
   late final Field i64ConstImmutableArrayCache =
       index.getTopLevelField('dart:_internal', 'i64ConstImmutableArray');
   late final Field boxedIntImmutableArrayCache =
@@ -468,6 +472,7 @@ mixin KernelNodes {
     _makeElementType(namedParameterClass): namedParameterConstArrayCache,
     _makeElementType(coreTypes.stringClass): stringConstArrayCache,
     _makeElementType(wasmI32Class): i32ConstArrayCache,
+    _makeElementType(wasmI16Class): i16ConstArrayCache,
     _makeElementType(wasmArrayClass,
         typeArguments: [_makeElementType(typeClass)]): typeArrayConstArrayCache,
   };
diff --git a/pkg/dart2wasm/lib/types.dart b/pkg/dart2wasm/lib/types.dart
index 1312caee186..c0d54025324 100644
--- a/pkg/dart2wasm/lib/types.dart
+++ b/pkg/dart2wasm/lib/types.dart
@@ -1249,6 +1249,8 @@ class RuntimeTypeInformation {
         InterfaceType(translator.typeClass, Nullability.nonNullable);
     final arrayOfType = InterfaceType(
         translator.wasmArrayClass, Nullability.nonNullable, [typeType]);
+    final wasmI16 =
+        InterfaceType(translator.wasmI16Class, Nullability.nonNullable);
     final wasmI32 =
         InterfaceType(translator.wasmI32Class, Nullability.nonNullable);
 
@@ -1260,17 +1262,21 @@ class RuntimeTypeInformation {
 
     rows.sort((Row a, Row b) => -weight(a).compareTo(weight(b)));
     final table = buildRowDisplacementTable(rows, firstAvailable: 1);
+    const invalidClassId = 0;
     final typeRowDisplacementTable = translator.constants.makeArrayOf(wasmI32, [
       for (final entry in table)
-        translator.constants.makeWasmI32(entry == null
-            ? 0
-            : (entry.$2 == noSubstitutionIndex ? -entry.$1 : entry.$1)),
+        translator.constants
+            .makeWasmI32(entry == null ? invalidClassId : entry.$1),
     ]);
     final typeRowDisplacementSubstTable =
-        translator.constants.makeArrayOf(arrayOfType, [
+        translator.constants.makeArrayOf(wasmI16, [
       for (final entry in table)
-        _substitutionTableByIndex[
-            entry == null ? noSubstitutionIndex : entry.$2],
+        translator.constants
+            .makeWasmI32(entry == null ? noSubstitutionIndex : entry.$2),
+    ]);
+    final canonicalSubstitutionTable =
+        translator.constants.makeArrayOf(arrayOfType, [
+      for (final sustitution in _substitutionTableByIndex) sustitution,
     ]);
 
     final typeRowDisplacementOffsets =
@@ -1288,8 +1294,9 @@ class RuntimeTypeInformation {
       translator.moduleRttOffsets.fieldReference: typeRowDisplacementOffsets,
       translator.moduleRttDisplacementTable.fieldReference:
           typeRowDisplacementTable,
-      translator.moduleRttSubstTable.fieldReference:
+      translator.moduleRttDisplacementSubstTable.fieldReference:
           typeRowDisplacementSubstTable,
+      translator.moduleRttSubstTable.fieldReference: canonicalSubstitutionTable,
       translator.moduleRttTypeNames.fieldReference: typeNames,
     });
   }
diff --git a/pkg/dart2wasm/test/ir_tests/deferred.constant.multi_module_use.wat b/pkg/dart2wasm/test/ir_tests/deferred.constant.multi_module_use.wat
index 35d0d9fbf44..01590b0d852 100644
--- a/pkg/dart2wasm/test/ir_tests/deferred.constant.multi_module_use.wat
+++ b/pkg/dart2wasm/test/ir_tests/deferred.constant.multi_module_use.wat
@@ -19,7 +19,7 @@
     (result (ref $MyConstClass))))
   (table $static0-0 (export "static0-0") 2 (ref null $type0))
   (table $static1-0 (export "static1-0") 1 (ref null $type2))
-  (global $"C383 \"bad\"" (ref $JSStringImpl) <...>)
+  (global $"C384 \"bad\"" (ref $JSStringImpl) <...>)
   (func $"mainImpl <noInline>" (param $var0 i32)
     (local $var1 (ref $MyConstClass))
     i64.const 0
@@ -35,7 +35,7 @@
     ref.eq
     i32.eqz
     if
-      global.get $"C383 \"bad\""
+      global.get $"C384 \"bad\""
       call $Error._throwWithCurrentStackTrace
       unreachable
     end
diff --git a/pkg/dart2wasm/test/ir_tests/deferred.constant.multi_module_use_module1.wat b/pkg/dart2wasm/test/ir_tests/deferred.constant.multi_module_use_module1.wat
index 830418166e4..3a6a464b604 100644
--- a/pkg/dart2wasm/test/ir_tests/deferred.constant.multi_module_use_module1.wat
+++ b/pkg/dart2wasm/test/ir_tests/deferred.constant.multi_module_use_module1.wat
@@ -16,7 +16,7 @@
     (result (ref $MyConstClass))))
   (global $.h0-nonshared-const (import "" "h0-nonshared-const") (ref extern))
   (table $module0.static1-0 (import "module0" "static1-0") 1 (ref null $type0))
-  (global $"C505 MyConstClass" (ref $MyConstClass)
+  (global $"C506 MyConstClass" (ref $MyConstClass)
     (i32.const 120)
     (i32.const 0)
     (i32.const 4)
@@ -27,7 +27,7 @@
   (func $"modH0Use <noInline>" (param $var0 i32) (result (ref $MyConstClass))
     local.get $var0
     if (result (ref $MyConstClass))
-      global.get $"C505 MyConstClass"
+      global.get $"C506 MyConstClass"
     else
       i32.const 0
       call_indirect $module0.static1-0 (result (ref $MyConstClass))
diff --git a/pkg/dart2wasm/test/ir_tests/deferred.constant.multi_module_use_module2.wat b/pkg/dart2wasm/test/ir_tests/deferred.constant.multi_module_use_module2.wat
index abe5e9b4153..ec61084d99b 100644
--- a/pkg/dart2wasm/test/ir_tests/deferred.constant.multi_module_use_module2.wat
+++ b/pkg/dart2wasm/test/ir_tests/deferred.constant.multi_module_use_module2.wat
@@ -13,7 +13,7 @@
     (field $field0 i32)
     (field $field1 (mut i32)))))
   (global $.shared-const (import "" "shared-const") (ref extern))
-  (global $"C503 MyConstClass" (ref $MyConstClass)
+  (global $"C504 MyConstClass" (ref $MyConstClass)
     (i32.const 120)
     (i32.const 0)
     (i32.const 4)
diff --git a/pkg/dart2wasm/test/ir_tests/deferred.constant.multi_module_use_module3.wat b/pkg/dart2wasm/test/ir_tests/deferred.constant.multi_module_use_module3.wat
index 7dd4862d50a..645388afabc 100644
--- a/pkg/dart2wasm/test/ir_tests/deferred.constant.multi_module_use_module3.wat
+++ b/pkg/dart2wasm/test/ir_tests/deferred.constant.multi_module_use_module3.wat
@@ -16,7 +16,7 @@
     (result (ref $MyConstClass))))
   (global $.h1-nonshared-const (import "" "h1-nonshared-const") (ref extern))
   (table $module0.static1-0 (import "module0" "static1-0") 1 (ref null $type0))
-  (global $"C501 MyConstClass" (ref $MyConstClass)
+  (global $"C502 MyConstClass" (ref $MyConstClass)
     (i32.const 120)
     (i32.const 0)
     (i32.const 4)
@@ -27,7 +27,7 @@
   (func $"modH1Use <noInline>" (param $var0 i32) (result (ref $MyConstClass))
     local.get $var0
     if (result (ref $MyConstClass))
-      global.get $"C501 MyConstClass"
+      global.get $"C502 MyConstClass"
     else
       i32.const 0
       call_indirect $module0.static1-0 (result (ref $MyConstClass))
diff --git a/pkg/dart2wasm/test/ir_tests/deferred.constant.type_use.wat b/pkg/dart2wasm/test/ir_tests/deferred.constant.type_use.wat
index fca83a44e10..94686a518b0 100644
--- a/pkg/dart2wasm/test/ir_tests/deferred.constant.type_use.wat
+++ b/pkg/dart2wasm/test/ir_tests/deferred.constant.type_use.wat
@@ -5,7 +5,7 @@
   (type $_InterfaceType <...>)
   (type $type0 <...>)
   (table $static0-0 (export "static0-0") 1 (ref null $type0))
-  (global $"C419 _InterfaceType" (ref $_InterfaceType) <...>)
+  (global $"C420 _InterfaceType" (ref $_InterfaceType) <...>)
   (func $_loaded implicit getter (result (ref $_DefaultSet&_HashFieldBase&SetMixin)) <...>)
   (func $"useFoo <noInline>"
     call $"useFooAsType <noInline>"
@@ -26,7 +26,7 @@
     drop
   )
   (func $"useFooAsType <noInline>"
-    global.get $"C419 _InterfaceType"
+    global.get $"C420 _InterfaceType"
     call $print
     drop
   )
diff --git a/pkg/dart2wasm/test/ir_tests/deferred.constant.type_use_module1.wat b/pkg/dart2wasm/test/ir_tests/deferred.constant.type_use_module1.wat
index f7e769c848f..52683bf16b0 100644
--- a/pkg/dart2wasm/test/ir_tests/deferred.constant.type_use_module1.wat
+++ b/pkg/dart2wasm/test/ir_tests/deferred.constant.type_use_module1.wat
@@ -7,7 +7,7 @@
   (type $JSStringImpl <...>)
   (type $Object <...>)
   (global $".Foo called " (import "" "Foo called ") (ref extern))
-  (global $"C467 \"Foo called \"" (ref $JSStringImpl)
+  (global $"C468 \"Foo called \"" (ref $JSStringImpl)
     (i32.const 4)
     (i32.const 0)
     (global.get $".Foo called ")
diff --git a/pkg/dart2wasm/test/ir_tests/deferred.constant_module1.wat b/pkg/dart2wasm/test/ir_tests/deferred.constant_module1.wat
index 29051842c8d..c25b05317f6 100644
--- a/pkg/dart2wasm/test/ir_tests/deferred.constant_module1.wat
+++ b/pkg/dart2wasm/test/ir_tests/deferred.constant_module1.wat
@@ -15,30 +15,30 @@
   (type $_TopType <...>)
   (func $print (import "module0" "func3") (param (ref null $#Top)) (result (ref null $#Top)))
   (global $"C1 WasmArray<_Type>[0]" (import "module0" "global1") (ref $Array<_Type>))
-  (global $"C319 WasmArray<_NamedParameter>[0]" (import "module0" "global4") (ref $Array<_NamedParameter>))
-  (global $"C344 _TopType" (import "module0" "global2") (ref $_TopType))
-  (global $"C63 WasmArray<_Type>[1]" (import "module0" "global3") (ref $Array<_Type>))
+  (global $"C320 WasmArray<_NamedParameter>[0]" (import "module0" "global4") (ref $Array<_NamedParameter>))
+  (global $"C345 _TopType" (import "module0" "global2") (ref $_TopType))
+  (global $"C64 WasmArray<_Type>[1]" (import "module0" "global3") (ref $Array<_Type>))
   (global $.globalH0Foo (import "" "globalH0Foo") (ref extern))
   (table $module0.constant-table0 (import "module0" "constant-table0") 1 (ref null $_FunctionType))
-  (global $"C478 globalH0Foo tear-off" (mut (ref null $#Closure-0-1))
+  (global $"C479 globalH0Foo tear-off" (mut (ref null $#Closure-0-1))
     (ref.null none))
-  (global $"C479 H0" (mut (ref null $H0))
+  (global $"C480 H0" (mut (ref null $H0))
     (ref.null none))
-  (global $"C480 \"globalH0Foo\"" (ref $JSStringImpl)
+  (global $"C481 \"globalH0Foo\"" (ref $JSStringImpl)
     (i32.const 4)
     (i32.const 0)
     (global.get $.globalH0Foo)
     (struct.new $JSStringImpl))
   (global $global0 (ref $#DummyStruct) <...>)
   (global $global2 (ref $#Vtable-0-1) <...>)
-  (func $"C479 H0 (lazy initializer)}" (result (ref $H0))
+  (func $"C480 H0 (lazy initializer)}" (result (ref $H0))
     (local $var0 (ref $_FunctionType))
     (local $var1 (ref $#Closure-0-1))
     (local $var2 (ref $H0))
     i32.const 118
     i32.const 0
     block $label0 (result (ref $#Closure-0-1))
-      global.get $"C478 globalH0Foo tear-off"
+      global.get $"C479 globalH0Foo tear-off"
       br_on_non_null $label0
       i32.const 38
       i32.const 0
@@ -55,10 +55,10 @@
         i64.const 0
         global.get $"C1 WasmArray<_Type>[0]"
         global.get $"C1 WasmArray<_Type>[0]"
-        global.get $"C344 _TopType"
-        global.get $"C63 WasmArray<_Type>[1]"
+        global.get $"C345 _TopType"
+        global.get $"C64 WasmArray<_Type>[1]"
         i64.const 1
-        global.get $"C319 WasmArray<_NamedParameter>[0]"
+        global.get $"C320 WasmArray<_NamedParameter>[0]"
         struct.new $_FunctionType
         local.tee $var0
         table.set $module0.constant-table0
@@ -66,20 +66,20 @@
       end $label1
       struct.new $#Closure-0-1
       local.tee $var1
-      global.set $"C478 globalH0Foo tear-off"
+      global.set $"C479 globalH0Foo tear-off"
       local.get $var1
     end $label0
     struct.new $H0
     local.tee $var2
-    global.set $"C479 H0"
+    global.set $"C480 H0"
     local.get $var2
   )
   (func $"globalH0Foo tear-off trampoline" (param $var0 (ref struct)) (param $var1 (ref null $#Top)) (result (ref null $#Top))
-    global.get $"C480 \"globalH0Foo\""
+    global.get $"C481 \"globalH0Foo\""
     call $print
   )
   (func $globalH0Foo (param $var0 i64) (result (ref null $#Top))
-    global.get $"C480 \"globalH0Foo\""
+    global.get $"C481 \"globalH0Foo\""
     call $print
   )
 )
\ No newline at end of file
diff --git a/pkg/dart2wasm/test/ir_tests/deferred.constant_module2.wat b/pkg/dart2wasm/test/ir_tests/deferred.constant_module2.wat
index 90226e4d08e..f32d6d3b626 100644
--- a/pkg/dart2wasm/test/ir_tests/deferred.constant_module2.wat
+++ b/pkg/dart2wasm/test/ir_tests/deferred.constant_module2.wat
@@ -26,28 +26,28 @@
   (global $"C1 WasmArray<_Type>[0]" (import "module0" "global1") (ref $Array<_Type>))
   (global $"C21 \")\"" (import "module0" "global0") (ref $JSStringImpl))
   (global $"C28 _InterfaceType" (import "module0" "global7") (ref $_InterfaceType))
-  (global $"C319 WasmArray<_NamedParameter>[0]" (import "module0" "global4") (ref $Array<_NamedParameter>))
-  (global $"C344 _TopType" (import "module0" "global2") (ref $_TopType))
-  (global $"C63 WasmArray<_Type>[1]" (import "module0" "global3") (ref $Array<_Type>))
+  (global $"C320 WasmArray<_NamedParameter>[0]" (import "module0" "global4") (ref $Array<_NamedParameter>))
+  (global $"C345 _TopType" (import "module0" "global2") (ref $_TopType))
+  (global $"C64 WasmArray<_Type>[1]" (import "module0" "global3") (ref $Array<_Type>))
   (global $.globalH1Bar< (import "" "globalH1Bar<") (ref extern))
   (table $module0.constant-table0 (import "module0" "constant-table0") 1 (ref null $_FunctionType))
-  (global $"C472 _FunctionType" (ref $_FunctionType) <...>)
-  (global $"C473 globalH1Foo tear-off" (mut (ref null $#Closure-1-1))
+  (global $"C473 _FunctionType" (ref $_FunctionType) <...>)
+  (global $"C474 globalH1Foo tear-off" (mut (ref null $#Closure-1-1))
     (ref.null none))
-  (global $"C474 InstantiationConstant(globalH1Foo<int>)" (mut (ref null $#Closure-0-1))
+  (global $"C475 InstantiationConstant(globalH1Foo<int>)" (mut (ref null $#Closure-0-1))
     (ref.null none))
-  (global $"C475 H1" (mut (ref null $H1))
+  (global $"C476 H1" (mut (ref null $H1))
     (ref.null none))
-  (global $"C476 \"globalH1Bar<\"" (ref $JSStringImpl)
+  (global $"C477 \"globalH1Bar<\"" (ref $JSStringImpl)
     (i32.const 4)
     (i32.const 0)
     (global.get $.globalH1Bar<)
     (struct.new $JSStringImpl))
-  (global $"C477 \">(\"" (ref $JSStringImpl) <...>)
+  (global $"C478 \">(\"" (ref $JSStringImpl) <...>)
   (global $global0 (ref $#DummyStruct) <...>)
   (global $global2 (ref $#Vtable-1-1) <...>)
   (func $#dummy function (ref struct) -> (ref null #Top) (param $var0 (ref struct)) (result (ref null $#Top)) <...>)
-  (func $"C475 H1 (lazy initializer)}" (result (ref $H1))
+  (func $"C476 H1 (lazy initializer)}" (result (ref $H1))
     (local $var0 (ref $#Closure-1-1))
     (local $var1 (ref $_FunctionType))
     (local $var2 (ref $#Closure-0-1))
@@ -55,21 +55,21 @@
     i32.const 119
     i32.const 0
     block $label0 (result (ref $#Closure-0-1))
-      global.get $"C474 InstantiationConstant(globalH1Foo<int>)"
+      global.get $"C475 InstantiationConstant(globalH1Foo<int>)"
       br_on_non_null $label0
       i32.const 38
       i32.const 0
       block $label1 (result (ref $#Closure-1-1))
-        global.get $"C473 globalH1Foo tear-off"
+        global.get $"C474 globalH1Foo tear-off"
         br_on_non_null $label1
         i32.const 38
         i32.const 0
         global.get $global0
         global.get $global2
-        global.get $"C472 _FunctionType"
+        global.get $"C473 _FunctionType"
         struct.new $#Closure-1-1
         local.tee $var0
-        global.set $"C473 globalH1Foo tear-off"
+        global.set $"C474 globalH1Foo tear-off"
         local.get $var0
       end $label1
       global.get $"C28 _InterfaceType"
@@ -88,10 +88,10 @@
         i64.const 0
         global.get $"C1 WasmArray<_Type>[0]"
         global.get $"C1 WasmArray<_Type>[0]"
-        global.get $"C344 _TopType"
-        global.get $"C63 WasmArray<_Type>[1]"
+        global.get $"C345 _TopType"
+        global.get $"C64 WasmArray<_Type>[1]"
         i64.const 1
-        global.get $"C319 WasmArray<_NamedParameter>[0]"
+        global.get $"C320 WasmArray<_NamedParameter>[0]"
         struct.new $_FunctionType
         local.tee $var1
         table.set $module0.constant-table0
@@ -99,18 +99,18 @@
       end $label2
       struct.new $#Closure-0-1
       local.tee $var2
-      global.set $"C474 InstantiationConstant(globalH1Foo<int>)"
+      global.set $"C475 InstantiationConstant(globalH1Foo<int>)"
       local.get $var2
     end $label0
     struct.new $H1
     local.tee $var3
-    global.set $"C475 H1"
+    global.set $"C476 H1"
     local.get $var3
   )
   (func $"globalH1Foo tear-off trampoline" (param $var0 (ref struct)) (param $var1 (ref $_Type)) (param $var2 (ref null $#Top)) (result (ref null $#Top))
-    global.get $"C476 \"globalH1Bar<\""
+    global.get $"C477 \"globalH1Bar<\""
     local.get $var1
-    global.get $"C477 \">(\""
+    global.get $"C478 \">(\""
     local.get $var2
     global.get $"C21 \")\""
     array.new_fixed $Array<Object?> 5
@@ -121,16 +121,16 @@
   (func $"modH1UseH1 <noInline>" (result (ref null $#Top))
     (local $var0 (ref $#Closure-0-1))
     block $label0 (result (ref $H1))
-      global.get $"C475 H1"
+      global.get $"C476 H1"
       br_on_non_null $label0
-      call $"C475 H1 (lazy initializer)}"
+      call $"C476 H1 (lazy initializer)}"
     end $label0
     call $print
     drop
     block $label1 (result (ref $H1))
-      global.get $"C475 H1"
+      global.get $"C476 H1"
       br_on_non_null $label1
-      call $"C475 H1 (lazy initializer)}"
+      call $"C476 H1 (lazy initializer)}"
     end $label1
     struct.get $H1 $fun
     local.tee $var0
diff --git a/pkg/dart2wasm/test/ir_tests/deferred.fine_grained.devirtualized.wat b/pkg/dart2wasm/test/ir_tests/deferred.fine_grained.devirtualized.wat
index f3d9635ee6d..123a8bfcf1f 100644
--- a/pkg/dart2wasm/test/ir_tests/deferred.fine_grained.devirtualized.wat
+++ b/pkg/dart2wasm/test/ir_tests/deferred.fine_grained.devirtualized.wat
@@ -7,17 +7,17 @@
   (global $".Foo1.doitDispatch(" (import "" "Foo1.doitDispatch(") (ref extern))
   (global $".FooBase(" (import "" "FooBase(") (ref extern))
   (table $static0-0 (export "static0-0") 1 (ref null $type0))
-  (global $"C385 \"FooBase(\"" (ref $JSStringImpl)
+  (global $"C386 \"FooBase(\"" (ref $JSStringImpl)
     (i32.const 4)
     (i32.const 0)
     (global.get $".FooBase(")
     (struct.new $JSStringImpl))
-  (global $"C386 \"Foo1.doitDispatch(\"" (ref $JSStringImpl)
+  (global $"C387 \"Foo1.doitDispatch(\"" (ref $JSStringImpl)
     (i32.const 4)
     (i32.const 0)
     (global.get $".Foo1.doitDispatch(")
     (struct.new $JSStringImpl))
-  (global $"C387 \"Foo0.doitDispatch(\"" (ref $JSStringImpl)
+  (global $"C388 \"Foo0.doitDispatch(\"" (ref $JSStringImpl)
     (i32.const 4)
     (i32.const 0)
     (global.get $".Foo0.doitDispatch(")
@@ -46,7 +46,7 @@
   )
   (func $runtimeTrue implicit getter (result i32) <...>)
   (func $Foo0.doitDispatch (param $var0 (ref $Object)) (param $var1 (ref null $#Top)) (result (ref null $#Top))
-    global.get $"C387 \"Foo0.doitDispatch(\""
+    global.get $"C388 \"Foo0.doitDispatch(\""
     local.get $var1
     global.get $"C8 \")\""
     call $JSStringImpl._interpolate3
@@ -58,7 +58,7 @@
   )
   (func $Foo1 (result (ref $Object)) <...>)
   (func $Foo1.doitDispatch (export "func1") (param $var0 (ref $Object)) (param $var1 (ref null $#Top)) (result (ref null $#Top))
-    global.get $"C386 \"Foo1.doitDispatch(\""
+    global.get $"C387 \"Foo1.doitDispatch(\""
     local.get $var1
     global.get $"C8 \")\""
     call $JSStringImpl._interpolate3
@@ -69,7 +69,7 @@
     ref.null none
   )
   (func $FooBase.doitDispatch (param $var0 (ref null $#Top))
-    global.get $"C385 \"FooBase(\""
+    global.get $"C386 \"FooBase(\""
     local.get $var0
     global.get $"C8 \")\""
     call $JSStringImpl._interpolate3
diff --git a/pkg/dart2wasm/test/ir_tests/deferred.fine_grained.devirtualized_module1.wat b/pkg/dart2wasm/test/ir_tests/deferred.fine_grained.devirtualized_module1.wat
index 0e45d2ce028..d5962c2eb24 100644
--- a/pkg/dart2wasm/test/ir_tests/deferred.fine_grained.devirtualized_module1.wat
+++ b/pkg/dart2wasm/test/ir_tests/deferred.fine_grained.devirtualized_module1.wat
@@ -8,14 +8,14 @@
   (func $JSStringImpl._interpolate3 (import "module0" "func2") (param (ref null $#Top) (ref null $#Top) (ref null $#Top)) (result (ref $JSStringImpl)))
   (func $print (import "module0" "func3") (param (ref null $#Top)) (result (ref null $#Top)))
   (global $".Foo1.doitDevirt(" (import "" "Foo1.doitDevirt(") (ref extern))
-  (global $"C317 1" (import "module0" "global1") (ref $BoxedInt))
-  (global $"C346 2" (import "module0" "global3") (ref $BoxedInt))
-  (global $"C385 \"FooBase(\"" (import "module0" "global5") (ref $JSStringImpl))
+  (global $"C318 1" (import "module0" "global1") (ref $BoxedInt))
+  (global $"C347 2" (import "module0" "global3") (ref $BoxedInt))
+  (global $"C386 \"FooBase(\"" (import "module0" "global5") (ref $JSStringImpl))
   (global $"C8 \")\"" (import "module0" "global4") (ref $JSStringImpl))
   (global $baseObj (import "module0" "global0") (ref null $Object))
   (global $foo1Obj (import "module0" "global2") (ref null $Object))
   (table $module0.dispatch0 (import "module0" "dispatch0") 773 funcref)
-  (global $"C504 \"Foo1.doitDevirt(\"" (ref $JSStringImpl)
+  (global $"C505 \"Foo1.doitDevirt(\"" (ref $JSStringImpl)
     (i32.const 4)
     (i32.const 0)
     (global.get $".Foo1.doitDevirt(")
@@ -29,7 +29,7 @@
         br $label0
       end $label1
       local.tee $var0
-      global.get $"C317 1"
+      global.get $"C318 1"
       local.get $var0
       struct.get $Object $field0
       i32.const 444
@@ -41,7 +41,7 @@
         br_on_non_null $label2
         br $label0
       end $label2
-      global.get $"C346 2"
+      global.get $"C347 2"
       call $Foo1.doitDispatch
       drop
       block $label3 (result (ref $Object))
@@ -63,14 +63,14 @@
     unreachable
   )
   (func $Foo1.doitDevirt (param $var0 (ref $Object))
-    global.get $"C504 \"Foo1.doitDevirt(\""
-    global.get $"C317 1"
+    global.get $"C505 \"Foo1.doitDevirt(\""
+    global.get $"C318 1"
     global.get $"C8 \")\""
     call $JSStringImpl._interpolate3
     call $print
     drop
-    global.get $"C385 \"FooBase(\""
-    global.get $"C317 1"
+    global.get $"C386 \"FooBase(\""
+    global.get $"C318 1"
     global.get $"C8 \")\""
     call $JSStringImpl._interpolate3
     call $print
diff --git a/pkg/dart2wasm/test/ir_tests/deferred.fine_grained.wat b/pkg/dart2wasm/test/ir_tests/deferred.fine_grained.wat
index a144bf60778..0d45969e868 100644
--- a/pkg/dart2wasm/test/ir_tests/deferred.fine_grained.wat
+++ b/pkg/dart2wasm/test/ir_tests/deferred.fine_grained.wat
@@ -14,29 +14,29 @@
   (table $static2-0 (export "static2-0") 4 (ref null $type4))
   (table $static3-0 (export "static3-0") 4 (ref null $type6))
   (global $"C12 0" (ref $BoxedInt) <...>)
-  (global $"C392 \"FooConstBase(\"" (ref $JSStringImpl)
+  (global $"C393 \"FooConstBase(\"" (ref $JSStringImpl)
     (i32.const 4)
     (i32.const 0)
     (global.get $".FooConstBase(")
     (struct.new $JSStringImpl))
-  (global $"C393 FooConst0" (ref $Object)
+  (global $"C394 FooConst0" (ref $Object)
     (i32.const 120)
     (i32.const 0)
     (struct.new $Object))
-  (global $"C394 \"FooConst0(\"" (ref $JSStringImpl)
+  (global $"C395 \"FooConst0(\"" (ref $JSStringImpl)
     (i32.const 4)
     (i32.const 0)
     (global.get $".FooConst0(")
     (struct.new $JSStringImpl))
-  (global $"C510 \"foo0Code(\"" (ref $JSStringImpl) <...>)
+  (global $"C511 \"foo0Code(\"" (ref $JSStringImpl) <...>)
   (global $"C8 \")\"" (ref $JSStringImpl) <...>)
   (global $fooGlobal0 (mut (ref null $#Top))
     (ref.null none))
   (func $"foo0Code <noInline>" (export "func12") (param $var0 (ref null $#Top)) (result (ref null $#Top))
-    global.get $"C393 FooConst0"
+    global.get $"C394 FooConst0"
     call $print
     drop
-    global.get $"C510 \"foo0Code(\""
+    global.get $"C511 \"foo0Code(\""
     local.get $var0
     global.get $"C8 \")\""
     call $JSStringImpl._interpolate3
@@ -47,7 +47,7 @@
     ref.null none
   )
   (func $FooConst0.doit (param $var0 (ref $Object)) (param $var1 (ref null $#Top)) (result (ref null $#Top))
-    global.get $"C394 \"FooConst0(\""
+    global.get $"C395 \"FooConst0(\""
     local.get $var1
     global.get $"C8 \")\""
     call $JSStringImpl._interpolate3
@@ -60,7 +60,7 @@
     ref.null none
   )
   (func $FooConstBase.doit (export "func14") (param $var0 (ref $Object)) (param $var1 (ref null $#Top)) (result (ref null $#Top))
-    global.get $"C392 \"FooConstBase(\""
+    global.get $"C393 \"FooConstBase(\""
     local.get $var1
     global.get $"C8 \")\""
     call $JSStringImpl._interpolate3
diff --git a/pkg/dart2wasm/test/ir_tests/deferred.fine_grained_module1.wat b/pkg/dart2wasm/test/ir_tests/deferred.fine_grained_module1.wat
index 2a1d43b6db0..ea7e1fecbb4 100644
--- a/pkg/dart2wasm/test/ir_tests/deferred.fine_grained_module1.wat
+++ b/pkg/dart2wasm/test/ir_tests/deferred.fine_grained_module1.wat
@@ -18,25 +18,25 @@
   (func $JSStringImpl._interpolate3 (import "module0" "func10") (param (ref null $#Top) (ref null $#Top) (ref null $#Top)) (result (ref $JSStringImpl)))
   (func $print (import "module0" "func9") (param (ref null $#Top)) (result (ref null $#Top)))
   (global $".FooConst5(" (import "" "FooConst5(") (ref extern))
-  (global $"C315 \"[]\"" (import "module0" "global6") (ref $JSStringImpl))
-  (global $"C391 5" (import "module0" "global5") (ref $BoxedInt))
-  (global $"C393 FooConst0" (import "module0" "global7") (ref $Object))
+  (global $"C316 \"[]\"" (import "module0" "global6") (ref $JSStringImpl))
+  (global $"C392 5" (import "module0" "global5") (ref $BoxedInt))
+  (global $"C394 FooConst0" (import "module0" "global7") (ref $Object))
   (global $"C8 \")\"" (import "module0" "global4") (ref $JSStringImpl))
   (table $module0.dispatch0 (import "module0" "dispatch0") 789 funcref)
   (table $module0.static1-0 (import "module0" "static1-0") 4 (ref null $type2))
   (table $module0.static2-0 (import "module0" "static2-0") 4 (ref null $type0))
   (table $module0.static3-0 (import "module0" "static3-0") 4 (ref null $type4))
-  (global $"C512 FooConst5" (ref $Object)
+  (global $"C513 FooConst5" (ref $Object)
     (i32.const 125)
     (i32.const 0)
     (struct.new $Object))
-  (global $"C513 \"foo5Code(\"" (ref $JSStringImpl) <...>)
-  (global $"C514 \"FooConst5(\"" (ref $JSStringImpl)
+  (global $"C514 \"foo5Code(\"" (ref $JSStringImpl) <...>)
+  (global $"C515 \"FooConst5(\"" (ref $JSStringImpl)
     (i32.const 4)
     (i32.const 0)
     (global.get $".FooConst5(")
     (struct.new $JSStringImpl))
-  (global $"C515 _InterfaceType" (ref $_InterfaceType) <...>)
+  (global $"C516 _InterfaceType" (ref $_InterfaceType) <...>)
   (global $allFooConstants (mut (ref null $WasmListBase))
     (ref.null none))
   (global $fooGlobal5 (mut (ref null $#Top))
@@ -46,16 +46,16 @@
     (local $var1 (ref $WasmListBase))
     (local $var2 (ref $Object))
     (local $var3 i64)
-    global.get $"C512 FooConst5"
+    global.get $"C513 FooConst5"
     call $print
     drop
-    global.get $"C513 \"foo5Code(\""
+    global.get $"C514 \"foo5Code(\""
     local.get $var0
     global.get $"C8 \")\""
     call $JSStringImpl._interpolate3
     call $print
     drop
-    global.get $"C391 5"
+    global.get $"C392 5"
     global.set $fooGlobal5
     call $"fooGlobal0 implicit getter"
     call $"foo0Code <noInline>"
@@ -83,8 +83,8 @@
     block $label0 (result (ref $WasmListBase))
       global.get $allFooConstants
       br_on_non_null $label0
-      global.get $"C515 _InterfaceType"
-      global.get $"C393 FooConst0"
+      global.get $"C516 _InterfaceType"
+      global.get $"C394 FooConst0"
       i32.const 0
       call_indirect $module0.static3-0 (result (ref $Object))
       i32.const 1
@@ -93,7 +93,7 @@
       call_indirect $module0.static3-0 (result (ref $Object))
       i32.const 3
       call_indirect $module0.static3-0 (result (ref $Object))
-      global.get $"C512 FooConst5"
+      global.get $"C513 FooConst5"
       array.new_fixed $Array<Object?> 6
       call $GrowableList._withData
       global.set $allFooConstants
@@ -107,7 +107,7 @@
     if
       i64.const 0
       local.get $var3
-      global.get $"C315 \"[]\""
+      global.get $"C316 \"[]\""
       call $"_throwIndexError <noInline>"
       unreachable
     end
@@ -127,7 +127,7 @@
   )
   (func $fooGlobal5 implicit getter (result (ref $#Top)) <...>)
   (func $FooConst5.doit (param $var0 (ref $Object)) (param $var1 (ref null $#Top)) (result (ref null $#Top))
-    global.get $"C514 \"FooConst5(\""
+    global.get $"C515 \"FooConst5(\""
     local.get $var1
     global.get $"C8 \")\""
     call $JSStringImpl._interpolate3
diff --git a/pkg/dart2wasm/test/ir_tests/deferred.fine_grained_module2.wat b/pkg/dart2wasm/test/ir_tests/deferred.fine_grained_module2.wat
index e96a06451e6..205adcfbd34 100644
--- a/pkg/dart2wasm/test/ir_tests/deferred.fine_grained_module2.wat
+++ b/pkg/dart2wasm/test/ir_tests/deferred.fine_grained_module2.wat
@@ -7,36 +7,36 @@
   (func $JSStringImpl._interpolate3 (import "module0" "func10") (param (ref null $#Top) (ref null $#Top) (ref null $#Top)) (result (ref $JSStringImpl)))
   (func $print (import "module0" "func9") (param (ref null $#Top)) (result (ref null $#Top)))
   (global $".FooConst1(" (import "" "FooConst1(") (ref extern))
-  (global $"C321 1" (import "module0" "global8") (ref $BoxedInt))
+  (global $"C322 1" (import "module0" "global8") (ref $BoxedInt))
   (global $"C8 \")\"" (import "module0" "global4") (ref $JSStringImpl))
-  (global $"C516 FooConst1" (ref $Object)
+  (global $"C517 FooConst1" (ref $Object)
     (i32.const 121)
     (i32.const 0)
     (struct.new $Object))
-  (global $"C523 \"FooConst1(\"" (ref $JSStringImpl)
+  (global $"C524 \"FooConst1(\"" (ref $JSStringImpl)
     (i32.const 4)
     (i32.const 0)
     (global.get $".FooConst1(")
     (struct.new $JSStringImpl))
-  (global $"C531 \"foo1Code(\"" (ref $JSStringImpl) <...>)
+  (global $"C532 \"foo1Code(\"" (ref $JSStringImpl) <...>)
   (global $fooGlobal1 (mut (ref null $#Top))
     (ref.null none))
   (func $"foo1Code <noInline>" (param $var0 (ref null $#Top)) (result (ref null $#Top))
-    global.get $"C516 FooConst1"
+    global.get $"C517 FooConst1"
     call $print
     drop
-    global.get $"C531 \"foo1Code(\""
+    global.get $"C532 \"foo1Code(\""
     local.get $var0
     global.get $"C8 \")\""
     call $JSStringImpl._interpolate3
     call $print
     drop
-    global.get $"C321 1"
+    global.get $"C322 1"
     global.set $fooGlobal1
     ref.null none
   )
   (func $FooConst1.doit (param $var0 (ref $Object)) (param $var1 (ref null $#Top)) (result (ref null $#Top))
-    global.get $"C523 \"FooConst1(\""
+    global.get $"C524 \"FooConst1(\""
     local.get $var1
     global.get $"C8 \")\""
     call $JSStringImpl._interpolate3
diff --git a/pkg/dart2wasm/test/ir_tests/deferred.fine_grained_module3.wat b/pkg/dart2wasm/test/ir_tests/deferred.fine_grained_module3.wat
index 1826b789116..10b2ec9d912 100644
--- a/pkg/dart2wasm/test/ir_tests/deferred.fine_grained_module3.wat
+++ b/pkg/dart2wasm/test/ir_tests/deferred.fine_grained_module3.wat
@@ -7,36 +7,36 @@
   (func $JSStringImpl._interpolate3 (import "module0" "func10") (param (ref null $#Top) (ref null $#Top) (ref null $#Top)) (result (ref $JSStringImpl)))
   (func $print (import "module0" "func9") (param (ref null $#Top)) (result (ref null $#Top)))
   (global $".FooConst2(" (import "" "FooConst2(") (ref extern))
-  (global $"C350 2" (import "module0" "global12") (ref $BoxedInt))
+  (global $"C351 2" (import "module0" "global12") (ref $BoxedInt))
   (global $"C8 \")\"" (import "module0" "global4") (ref $JSStringImpl))
-  (global $"C517 FooConst2" (ref $Object)
+  (global $"C518 FooConst2" (ref $Object)
     (i32.const 122)
     (i32.const 0)
     (struct.new $Object))
-  (global $"C522 \"FooConst2(\"" (ref $JSStringImpl)
+  (global $"C523 \"FooConst2(\"" (ref $JSStringImpl)
     (i32.const 4)
     (i32.const 0)
     (global.get $".FooConst2(")
     (struct.new $JSStringImpl))
-  (global $"C530 \"foo2Code(\"" (ref $JSStringImpl) <...>)
+  (global $"C531 \"foo2Code(\"" (ref $JSStringImpl) <...>)
   (global $fooGlobal2 (mut (ref null $#Top))
     (ref.null none))
   (func $"foo2Code <noInline>" (param $var0 (ref null $#Top)) (result (ref null $#Top))
-    global.get $"C517 FooConst2"
+    global.get $"C518 FooConst2"
     call $print
     drop
-    global.get $"C530 \"foo2Code(\""
+    global.get $"C531 \"foo2Code(\""
     local.get $var0
     global.get $"C8 \")\""
     call $JSStringImpl._interpolate3
     call $print
     drop
-    global.get $"C350 2"
+    global.get $"C351 2"
     global.set $fooGlobal2
     ref.null none
   )
   (func $FooConst2.doit (param $var0 (ref $Object)) (param $var1 (ref null $#Top)) (result (ref null $#Top))
-    global.get $"C522 \"FooConst2(\""
+    global.get $"C523 \"FooConst2(\""
     local.get $var1
     global.get $"C8 \")\""
     call $JSStringImpl._interpolate3
diff --git a/pkg/dart2wasm/test/ir_tests/deferred.fine_grained_module4.wat b/pkg/dart2wasm/test/ir_tests/deferred.fine_grained_module4.wat
index 5001a31632e..6a9e855bb19 100644
--- a/pkg/dart2wasm/test/ir_tests/deferred.fine_grained_module4.wat
+++ b/pkg/dart2wasm/test/ir_tests/deferred.fine_grained_module4.wat
@@ -7,36 +7,36 @@
   (func $JSStringImpl._interpolate3 (import "module0" "func10") (param (ref null $#Top) (ref null $#Top) (ref null $#Top)) (result (ref $JSStringImpl)))
   (func $print (import "module0" "func9") (param (ref null $#Top)) (result (ref null $#Top)))
   (global $".FooConst3(" (import "" "FooConst3(") (ref extern))
-  (global $"C429 3" (import "module0" "global11") (ref $BoxedInt))
+  (global $"C430 3" (import "module0" "global11") (ref $BoxedInt))
   (global $"C8 \")\"" (import "module0" "global4") (ref $JSStringImpl))
-  (global $"C518 FooConst3" (ref $Object)
+  (global $"C519 FooConst3" (ref $Object)
     (i32.const 123)
     (i32.const 0)
     (struct.new $Object))
-  (global $"C521 \"FooConst3(\"" (ref $JSStringImpl)
+  (global $"C522 \"FooConst3(\"" (ref $JSStringImpl)
     (i32.const 4)
     (i32.const 0)
     (global.get $".FooConst3(")
     (struct.new $JSStringImpl))
-  (global $"C529 \"foo3Code(\"" (ref $JSStringImpl) <...>)
+  (global $"C530 \"foo3Code(\"" (ref $JSStringImpl) <...>)
   (global $fooGlobal3 (mut (ref null $#Top))
     (ref.null none))
   (func $"foo3Code <noInline>" (param $var0 (ref null $#Top)) (result (ref null $#Top))
-    global.get $"C518 FooConst3"
+    global.get $"C519 FooConst3"
     call $print
     drop
-    global.get $"C529 \"foo3Code(\""
+    global.get $"C530 \"foo3Code(\""
     local.get $var0
     global.get $"C8 \")\""
     call $JSStringImpl._interpolate3
     call $print
     drop
-    global.get $"C429 3"
+    global.get $"C430 3"
     global.set $fooGlobal3
     ref.null none
   )
   (func $FooConst3.doit (param $var0 (ref $Object)) (param $var1 (ref null $#Top)) (result (ref null $#Top))
-    global.get $"C521 \"FooConst3(\""
+    global.get $"C522 \"FooConst3(\""
     local.get $var1
     global.get $"C8 \")\""
     call $JSStringImpl._interpolate3
diff --git a/pkg/dart2wasm/test/ir_tests/deferred.fine_grained_module5.wat b/pkg/dart2wasm/test/ir_tests/deferred.fine_grained_module5.wat
index 2488b7f2699..bea75bab05b 100644
--- a/pkg/dart2wasm/test/ir_tests/deferred.fine_grained_module5.wat
+++ b/pkg/dart2wasm/test/ir_tests/deferred.fine_grained_module5.wat
@@ -7,36 +7,36 @@
   (func $JSStringImpl._interpolate3 (import "module0" "func10") (param (ref null $#Top) (ref null $#Top) (ref null $#Top)) (result (ref $JSStringImpl)))
   (func $print (import "module0" "func9") (param (ref null $#Top)) (result (ref null $#Top)))
   (global $".FooConst4(" (import "" "FooConst4(") (ref extern))
-  (global $"C369 4" (import "module0" "global10") (ref $BoxedInt))
+  (global $"C370 4" (import "module0" "global10") (ref $BoxedInt))
   (global $"C8 \")\"" (import "module0" "global4") (ref $JSStringImpl))
-  (global $"C519 FooConst4" (ref $Object)
+  (global $"C520 FooConst4" (ref $Object)
     (i32.const 124)
     (i32.const 0)
     (struct.new $Object))
-  (global $"C520 \"FooConst4(\"" (ref $JSStringImpl)
+  (global $"C521 \"FooConst4(\"" (ref $JSStringImpl)
     (i32.const 4)
     (i32.const 0)
     (global.get $".FooConst4(")
     (struct.new $JSStringImpl))
-  (global $"C528 \"foo4Code(\"" (ref $JSStringImpl) <...>)
+  (global $"C529 \"foo4Code(\"" (ref $JSStringImpl) <...>)
   (global $fooGlobal4 (mut (ref null $#Top))
     (ref.null none))
   (func $"foo4Code <noInline>" (param $var0 (ref null $#Top)) (result (ref null $#Top))
-    global.get $"C519 FooConst4"
+    global.get $"C520 FooConst4"
     call $print
     drop
-    global.get $"C528 \"foo4Code(\""
+    global.get $"C529 \"foo4Code(\""
     local.get $var0
     global.get $"C8 \")\""
     call $JSStringImpl._interpolate3
     call $print
     drop
-    global.get $"C369 4"
+    global.get $"C370 4"
     global.set $fooGlobal4
     ref.null none
   )
   (func $FooConst4.doit (param $var0 (ref $Object)) (param $var1 (ref null $#Top)) (result (ref null $#Top))
-    global.get $"C520 \"FooConst4(\""
+    global.get $"C521 \"FooConst4(\""
     local.get $var1
     global.get $"C8 \")\""
     call $JSStringImpl._interpolate3
diff --git a/pkg/dart2wasm/test/ir_tests/dyn_closure.wat b/pkg/dart2wasm/test/ir_tests/dyn_closure.wat
index 5009545a2a3..0b339c03dd6 100644
--- a/pkg/dart2wasm/test/ir_tests/dyn_closure.wat
+++ b/pkg/dart2wasm/test/ir_tests/dyn_closure.wat
@@ -20,9 +20,9 @@
   (type $type2 <...>)
   (global $"C1 WasmArray<_Type>[0]" (ref $Array<_Type>) <...>)
   (global $"C28 _InterfaceType" (ref $_InterfaceType) <...>)
-  (global $"C316 WasmArray<_NamedParameter>[0]" (ref $Array<_NamedParameter>) <...>)
-  (global $"C342 _TopType" (ref $_TopType) <...>)
-  (global $"C346 foo tear-off" (ref $#Closure-0-2)
+  (global $"C317 WasmArray<_NamedParameter>[0]" (ref $Array<_NamedParameter>) <...>)
+  (global $"C343 _TopType" (ref $_TopType) <...>)
+  (global $"C347 foo tear-off" (ref $#Closure-0-2)
     (i32.const 56)
     (i32.const 0)
     (global.get $global0)
@@ -34,7 +34,7 @@
     (i32.const 0)
     (global.get $"C1 WasmArray<_Type>[0]")
     (global.get $"C1 WasmArray<_Type>[0]")
-    (global.get $"C342 _TopType")
+    (global.get $"C343 _TopType")
     (global.get $"C28 _InterfaceType")
     (i32.const 10)
     (i32.const 0)
@@ -44,10 +44,10 @@
     (struct.new $_InterfaceType)
     (array.new_fixed $Array<_Type> 2)
     (i64.const 1)
-    (global.get $"C316 WasmArray<_NamedParameter>[0]")
+    (global.get $"C317 WasmArray<_NamedParameter>[0]")
     (struct.new $_FunctionType)
     (struct.new $#Closure-0-2))
-  (global $"C350 bar tear-off" (ref $#Closure-0-2)
+  (global $"C351 bar tear-off" (ref $#Closure-0-2)
     (i32.const 56)
     (i32.const 0)
     (global.get $global0)
@@ -59,7 +59,7 @@
     (i32.const 0)
     (global.get $"C1 WasmArray<_Type>[0]")
     (global.get $"C1 WasmArray<_Type>[0]")
-    (global.get $"C342 _TopType")
+    (global.get $"C343 _TopType")
     (global.get $"C28 _InterfaceType")
     (i32.const 10)
     (i32.const 0)
@@ -69,7 +69,7 @@
     (struct.new $_InterfaceType)
     (array.new_fixed $Array<_Type> 2)
     (i64.const 1)
-    (global.get $"C316 WasmArray<_NamedParameter>[0]")
+    (global.get $"C317 WasmArray<_NamedParameter>[0]")
     (struct.new $_FunctionType)
     (struct.new $#Closure-0-2))
   (global $global0 (ref $#DummyStruct) <...>)
diff --git a/pkg/dart2wasm/test/ir_tests/dyn_closure_function_apply.wat b/pkg/dart2wasm/test/ir_tests/dyn_closure_function_apply.wat
index 90c7aae5324..6592f029c26 100644
--- a/pkg/dart2wasm/test/ir_tests/dyn_closure_function_apply.wat
+++ b/pkg/dart2wasm/test/ir_tests/dyn_closure_function_apply.wat
@@ -20,9 +20,9 @@
   (type $type2 <...>)
   (global $"C1 WasmArray<_Type>[0]" (ref $Array<_Type>) <...>)
   (global $"C28 _InterfaceType" (ref $_InterfaceType) <...>)
-  (global $"C316 WasmArray<_NamedParameter>[0]" (ref $Array<_NamedParameter>) <...>)
-  (global $"C342 _TopType" (ref $_TopType) <...>)
-  (global $"C346 foo tear-off" (ref $#Closure-0-2)
+  (global $"C317 WasmArray<_NamedParameter>[0]" (ref $Array<_NamedParameter>) <...>)
+  (global $"C343 _TopType" (ref $_TopType) <...>)
+  (global $"C347 foo tear-off" (ref $#Closure-0-2)
     (i32.const 56)
     (i32.const 0)
     (global.get $global0)
@@ -34,7 +34,7 @@
     (i32.const 0)
     (global.get $"C1 WasmArray<_Type>[0]")
     (global.get $"C1 WasmArray<_Type>[0]")
-    (global.get $"C342 _TopType")
+    (global.get $"C343 _TopType")
     (global.get $"C28 _InterfaceType")
     (i32.const 10)
     (i32.const 0)
@@ -44,10 +44,10 @@
     (struct.new $_InterfaceType)
     (array.new_fixed $Array<_Type> 2)
     (i64.const 1)
-    (global.get $"C316 WasmArray<_NamedParameter>[0]")
+    (global.get $"C317 WasmArray<_NamedParameter>[0]")
     (struct.new $_FunctionType)
     (struct.new $#Closure-0-2))
-  (global $"C351 bar tear-off" (ref $#Closure-0-2)
+  (global $"C352 bar tear-off" (ref $#Closure-0-2)
     (i32.const 56)
     (i32.const 0)
     (global.get $global0)
@@ -59,7 +59,7 @@
     (i32.const 0)
     (global.get $"C1 WasmArray<_Type>[0]")
     (global.get $"C1 WasmArray<_Type>[0]")
-    (global.get $"C342 _TopType")
+    (global.get $"C343 _TopType")
     (global.get $"C28 _InterfaceType")
     (i32.const 10)
     (i32.const 0)
@@ -69,7 +69,7 @@
     (struct.new $_InterfaceType)
     (array.new_fixed $Array<_Type> 2)
     (i64.const 1)
-    (global.get $"C316 WasmArray<_NamedParameter>[0]")
+    (global.get $"C317 WasmArray<_NamedParameter>[0]")
     (struct.new $_FunctionType)
     (struct.new $#Closure-0-2))
   (global $global0 (ref $#DummyStruct) <...>)
diff --git a/pkg/dart2wasm/test/ir_tests/dyn_closure_function_apply_named.wat b/pkg/dart2wasm/test/ir_tests/dyn_closure_function_apply_named.wat
index edcc5027d78..2123b909597 100644
--- a/pkg/dart2wasm/test/ir_tests/dyn_closure_function_apply_named.wat
+++ b/pkg/dart2wasm/test/ir_tests/dyn_closure_function_apply_named.wat
@@ -24,9 +24,9 @@
   (type $type2 <...>)
   (global $"C1 WasmArray<_Type>[0]" (ref $Array<_Type>) <...>)
   (global $"C28 _InterfaceType" (ref $_InterfaceType) <...>)
-  (global $"C316 WasmArray<_NamedParameter>[0]" (ref $Array<_NamedParameter>) <...>)
-  (global $"C342 _TopType" (ref $_TopType) <...>)
-  (global $"C346 foo tear-off" (ref $#Closure-0-2)
+  (global $"C317 WasmArray<_NamedParameter>[0]" (ref $Array<_NamedParameter>) <...>)
+  (global $"C343 _TopType" (ref $_TopType) <...>)
+  (global $"C347 foo tear-off" (ref $#Closure-0-2)
     (i32.const 56)
     (i32.const 0)
     (global.get $global0)
@@ -38,7 +38,7 @@
     (i32.const 0)
     (global.get $"C1 WasmArray<_Type>[0]")
     (global.get $"C1 WasmArray<_Type>[0]")
-    (global.get $"C342 _TopType")
+    (global.get $"C343 _TopType")
     (global.get $"C28 _InterfaceType")
     (i32.const 10)
     (i32.const 0)
@@ -48,11 +48,11 @@
     (struct.new $_InterfaceType)
     (array.new_fixed $Array<_Type> 2)
     (i64.const 1)
-    (global.get $"C316 WasmArray<_NamedParameter>[0]")
+    (global.get $"C317 WasmArray<_NamedParameter>[0]")
     (struct.new $_FunctionType)
     (struct.new $#Closure-0-2))
-  (global $"C348 _InterfaceType" (ref $_InterfaceType) <...>)
-  (global $"C351 bar tear-off" (ref $#Closure-0-2)
+  (global $"C349 _InterfaceType" (ref $_InterfaceType) <...>)
+  (global $"C352 bar tear-off" (ref $#Closure-0-2)
     (i32.const 56)
     (i32.const 0)
     (global.get $global0)
@@ -64,12 +64,12 @@
     (i32.const 0)
     (global.get $"C1 WasmArray<_Type>[0]")
     (global.get $"C1 WasmArray<_Type>[0]")
-    (global.get $"C342 _TopType")
+    (global.get $"C343 _TopType")
     (global.get $"C28 _InterfaceType")
-    (global.get $"C348 _InterfaceType")
+    (global.get $"C349 _InterfaceType")
     (array.new_fixed $Array<_Type> 2)
     (i64.const 1)
-    (global.get $"C316 WasmArray<_NamedParameter>[0]")
+    (global.get $"C317 WasmArray<_NamedParameter>[0]")
     (struct.new $_FunctionType)
     (struct.new $#Closure-0-2))
   (global $global0 (ref $#DummyStruct) <...>)
diff --git a/pkg/dart2wasm/test/ir_tests/hello.wat b/pkg/dart2wasm/test/ir_tests/hello.wat
index aa293a5cbd5..6cbc00aa2b2 100644
--- a/pkg/dart2wasm/test/ir_tests/hello.wat
+++ b/pkg/dart2wasm/test/ir_tests/hello.wat
@@ -5,12 +5,12 @@
     (field $field0 i32)
     (field $_ref externref))))
   (global $".hello world" (import "" "hello world") (ref extern))
-  (global $"C340 \"hello world\"" (ref $JSStringImpl)
+  (global $"C341 \"hello world\"" (ref $JSStringImpl)
     (i32.const 4)
     (global.get $".hello world")
     (struct.new $JSStringImpl))
   (func $"main <noInline>"
-    global.get $"C340 \"hello world\""
+    global.get $"C341 \"hello world\""
     call $print
   )
   (func $print (param $var0 (ref $#Top)) <...>)
diff --git a/pkg/dart2wasm/test/ir_tests/import_name_module1.wat b/pkg/dart2wasm/test/ir_tests/import_name_module1.wat
index 2fe1a1fea01..ad3be8ee9ac 100644
--- a/pkg/dart2wasm/test/ir_tests/import_name_module1.wat
+++ b/pkg/dart2wasm/test/ir_tests/import_name_module1.wat
@@ -10,7 +10,7 @@
     (field $field1 (mut i32)))))
   (func $print (import "module0" "func0") (param (ref null $#Top)) (result (ref null $#Top)))
   (global $".hello world" (import "" "hello world") (ref extern))
-  (global $"C465 \"hello world\"" (ref $JSStringImpl)
+  (global $"C466 \"hello world\"" (ref $JSStringImpl)
     (i32.const 4)
     (i32.const 0)
     (global.get $".hello world")
@@ -20,7 +20,7 @@
     ref.null none
   )
   (func $"mainFoo <noInline>"
-    global.get $"C465 \"hello world\""
+    global.get $"C466 \"hello world\""
     call $print
     drop
   )
diff --git a/sdk/lib/_internal/wasm/lib/dynamic_module.dart b/sdk/lib/_internal/wasm/lib/dynamic_module.dart
index 347a2386b62..d438f17534a 100644
--- a/sdk/lib/_internal/wasm/lib/dynamic_module.dart
+++ b/sdk/lib/_internal/wasm/lib/dynamic_module.dart
@@ -113,6 +113,8 @@ final nameParameterConstArray = WasmArrayConstCache();
 @pragma('dyn-module:callable')
 final i8ConstImmutableArray = WasmArrayConstCache();
 @pragma('dyn-module:callable')
+final i16ConstArray = WasmArrayConstCache();
+@pragma('dyn-module:callable')
 final i32ConstArray = WasmArrayConstCache();
 @pragma('dyn-module:callable')
 final i64ConstImmutableArray = WasmArrayConstCache();
diff --git a/sdk/lib/_internal/wasm/lib/type.dart b/sdk/lib/_internal/wasm/lib/type.dart
index f6d62ce7ec2..e792bdff64a 100644
--- a/sdk/lib/_internal/wasm/lib/type.dart
+++ b/sdk/lib/_internal/wasm/lib/type.dart
@@ -661,7 +661,7 @@ class _RecordType extends _Type {
       identical(names, other.names);
 }
 
-/// The non-negative index into [_ModuleRtt.typeRowDisplacementSubstTable] that
+/// The non-negative index into [_ModuleRtt.canonicalSubstitutionTable] that
 /// represents that no substitution is needed.
 external WasmI32 get _noSubstitutionIndex;
 
@@ -697,12 +697,15 @@ class _ModuleRtt {
   ///
   /// Used via
   /// ```
-  ///    baseOffset = _typeRowDisplacementOffsets[Base.classId]`
+  ///    baseOffset = typeRowDisplacementOffsets[Base.classId]`
   ///    index = baseOffset + Sub.classId
-  ///    value = _typeRowDisplacementTable[index]
+  ///    value = typeRowDisplacementTable[index]
   ///    if (value == Base.classId) {
   ///      // => Sub.classId is a subclass of Base.classId
-  ///      // => Can use `index` into `typeRowDisplacementSubstTable[index]`
+  ///      // => Can find how to translate Sub's type parameters to Base's type
+  ///      //    parameters via substitution:
+  ///      substIndex = typeRowDisplacementSubstTable[index];
+  ///      substitution = canonicalSubstitutionTable[substIndex]
   ///    }
   ///```
   ///
@@ -711,17 +714,23 @@ class _ModuleRtt {
   /// are ignored for all other compilations.
   final WasmArray<WasmI32> typeRowDisplacementTable;
 
-  /// Holds the canonical type argument substitution index for matching table
-  /// entries (see above).
+  /// Same entries and indexing scheme as [typeRowDisplacementTable] but stores
+  /// the index into [canonicalSubstitutionTable].
   ///
-  /// If `index` matches in [typeRowDisplacementTable] then the same index can be
-  /// used in this array to find the type argument substitution array for
-  /// translating type arguments from a base class to a direct/indirect class.
+  /// We use WasmI16 as we don't expect there to be more than 64k type
+  /// substitutions.
+  final WasmArray<WasmI16> typeRowDisplacementSubstTable;
+
+  /// Holds the canonical type argument substitutions.
   ///
-  /// Takes two class IDs of classes to be queried. For dynamic modules this will
-  /// allow the compiler to scope the query to a specific module. The class IDs
-  /// are ignored for all other compilations.
-  final WasmArray<WasmArray<_Type>> typeRowDisplacementSubstTable;
+  /// The entries can be used to translate type arguments from a subclass to the
+  /// type arguments of a super class.
+  ///
+  /// This array is indexed by values stores in the
+  /// [typeRowDisplacementSubstTable].
+  ///
+  /// (See [typeRowDisplacementTable] above for more information).
+  final WasmArray<WasmArray<_Type>> canonicalSubstitutionTable;
 
   /// The names of all classes (indexed by class id) or null (if `--minify` was
   /// used)
@@ -732,6 +741,7 @@ class _ModuleRtt {
     this.typeRowDisplacementOffsets,
     this.typeRowDisplacementTable,
     this.typeRowDisplacementSubstTable,
+    this.canonicalSubstitutionTable,
     this.typeNames,
   );
 }
@@ -1023,7 +1033,7 @@ abstract class _TypeUniverse {
       substitutionIndex,
       // Since these are already proved to be subclasses, sId and tId are in the
       // same module or sId's module contains info for both.
-      _moduleRttForClassId(sId).typeRowDisplacementSubstTable,
+      _moduleRttForClassId(sId).canonicalSubstitutionTable,
     );
   }
 
@@ -1051,7 +1061,7 @@ abstract class _TypeUniverse {
       substitutionIndex,
       // Since these are already proved to be subclasses, sId and tId are in the
       // same module or sId's module contains info for both.
-      _moduleRttForClassId(sId).typeRowDisplacementSubstTable,
+      _moduleRttForClassId(sId).canonicalSubstitutionTable,
     );
   }
 
@@ -1076,7 +1086,7 @@ abstract class _TypeUniverse {
       substitutionIndex,
       // Since these are already proved to be subclasses, sId and tId are in the
       // same module or sId's module contains info for both.
-      _moduleRttForClassId(sId).typeRowDisplacementSubstTable,
+      _moduleRttForClassId(sId).canonicalSubstitutionTable,
     );
   }
 
@@ -1105,7 +1115,7 @@ abstract class _TypeUniverse {
       substitutionIndex,
       // Since these are already proved to be subclasses, sId and tId are in the
       // same module or sId's module contains info for both.
-      _moduleRttForClassId(sId).typeRowDisplacementSubstTable,
+      _moduleRttForClassId(sId).canonicalSubstitutionTable,
     );
   }
 
@@ -1195,12 +1205,17 @@ abstract class _TypeUniverse {
     return true;
   }
 
-  /// Checks that [sId] is direct/indirect subclass of [tId] and obtains
+  /// Checks whether [sId] is direct/indirect subclass of [tId] and obtains
   /// substitution array index to translate [sId]s type arguments to [tId]s
   /// type arguments.
   ///
-  /// Returns `null` if [sId] does not have [tId] in its transitive
-  /// extends/implements chain or
+  /// Returns
+  ///   * -1 if the [sId] is not a subtype of [tId]
+  ///   * [_noSubstitutionIndex] if the classes are related but no type
+  ///     arguments have to be translated (either classes are not generic or
+  ///     their type arguments are identical and don't have to be translated)
+  ///   * otherwise returns an index that can be used to index
+  ///     [_ModuleRtt.canonicalSubstitutionTable]
   @pragma('wasm:prefer-inline')
   static WasmI32 _checkSubclassRelationship(WasmI32 sId, WasmI32 tId) {
     // Caller should ensure that the target cannot be a top type (which is
@@ -1229,8 +1244,12 @@ abstract class _TypeUniverse {
     final WasmI32 index = offset[tId.toIntSigned()] + sId;
     if (index.geU(table.length.toWasmI32())) return (-1).toWasmI32();
     final value = table[index.toIntSigned()];
-    if (value == tId) return index;
-    if (value == -tId) return _noSubstitutionIndex;
+    if (value == tId) {
+      // Match: The [sId] is a subtype of [tId].
+      return rtt.typeRowDisplacementSubstTable
+          .readUnsigned(index.toIntSigned())
+          .toWasmI32();
+    }
     return (-1).toWasmI32();
   }