diff --git a/pkg/dart2wasm/lib/io_util.dart b/pkg/dart2wasm/lib/io_util.dart
index 2d8666a3f54..f57035fb857 100644
--- a/pkg/dart2wasm/lib/io_util.dart
+++ b/pkg/dart2wasm/lib/io_util.dart
@@ -127,7 +127,8 @@ class CompilerPhaseInputOutputManager {
     final wasmOptPath = options.wasmOptPath?.toFilePath() ?? 'wasm-opt';
     final result = await _runProcess(wasmOptPath, args);
     if (result.exitCode != 0) {
-      throw Exception('wasm-opt failed with exit code ${result.exitCode}:'
+      throw Exception(
+          'wasm-opt failed on module $inputModuleName with exit code ${result.exitCode}:'
           '\n${result.stdout}\n${result.stderr}');
     }
   }
diff --git a/pkg/dart2wasm/lib/translator.dart b/pkg/dart2wasm/lib/translator.dart
index 6ce0069cd2e..64572748046 100644
--- a/pkg/dart2wasm/lib/translator.dart
+++ b/pkg/dart2wasm/lib/translator.dart
@@ -1695,10 +1695,13 @@ class Translator with KernelNodes {
         return null;
       }
 
+      final entryReference =
+          getFunctionEntry(member.reference, uncheckedEntry: false);
+
       return SingleClosureTarget._(
         member,
-        paramInfoForDirectCall(member.reference),
-        signatureForDirectCall(member.reference),
+        paramInfoForDirectCall(entryReference),
+        signatureForDirectCall(entryReference),
         null,
       );
     } else {
diff --git a/pkg/dart2wasm/tool/compile_benchmark b/pkg/dart2wasm/tool/compile_benchmark
index c1e900eeae8..f5aa8e28863 100755
--- a/pkg/dart2wasm/tool/compile_benchmark
+++ b/pkg/dart2wasm/tool/compile_benchmark
@@ -72,6 +72,7 @@ VM_ARGS=()
 DART2WASM_ARGS=("--require-js-string-builtin")
 DART_FILE=""
 OUTPUT_FILE=""
+PHASES=""
 while [ $# -gt 0 ]; do
     case "$1" in
       --compile-benchmark=*)
@@ -102,6 +103,11 @@ while [ $# -gt 0 ]; do
       shift
       ;;
 
+    --phases=*)
+      PHASES="${1#--phases=}"
+      shift
+      ;;
+
     --extra-compiler-option=--platform=*)
       PLATFORM_FILENAME="${1#--extra-compiler-option=--platform=}"
       shift
@@ -156,6 +162,10 @@ if [ -z "$DART_FILE" -o -z "$OUTPUT_FILE" ]; then
   exit 1
 fi
 
+if [ -z "$PHASES" ]; then
+  PHASES="cfe,tfa,codegen"
+fi
+
 
 PLATFORM_ARG="--platform=$PLATFORM_FILENAME"
 DART2WASM_AOT_SNAPSHOT="$BIN_DIR/$SNAPSHOT_NAME.snapshot"
@@ -192,9 +202,9 @@ COMPILER_GZIP_SIZE=0
 
 function run_compiler() {
   if [ $RUN_SRC -eq 1 ]; then
-    dart2wasm_command=("$DART" "${VM_ARGS[@]}" "$DART2WASM_SRC" "$LIBRARIES_JSON_ARG" "${DART2WASM_ARGS[@]}" "--phases=cfe,tfa,codegen" "$DART_FILE" "$OUTPUT_FILE")
+    dart2wasm_command=("$DART" "${VM_ARGS[@]}" "$DART2WASM_SRC" "$LIBRARIES_JSON_ARG" "${DART2WASM_ARGS[@]}" "--phases=$PHASES" "$DART_FILE" "$OUTPUT_FILE")
   else
-    dart2wasm_command=("$DART_AOT_RUNTIME" "${VM_ARGS[@]}" "$DART2WASM_AOT_SNAPSHOT" "$PLATFORM_ARG" "${DART2WASM_ARGS[@]}" "--phases=cfe,tfa,codegen" "$DART_FILE" "$OUTPUT_FILE")
+    dart2wasm_command=("$DART_AOT_RUNTIME" "${VM_ARGS[@]}" "$DART2WASM_AOT_SNAPSHOT" "$PLATFORM_ARG" "${DART2WASM_ARGS[@]}" "--phases=$PHASES" "$DART_FILE" "$OUTPUT_FILE")
   fi
 
   if [ -n "$COMPILE_BENCHMARK_BASE_NAME" ]; then
diff --git a/tests/language/closure/dynamic_closure_param_test.dart b/tests/language/closure/dynamic_closure_param_test.dart
new file mode 100644
index 00000000000..c16111ab5d9
--- /dev/null
+++ b/tests/language/closure/dynamic_closure_param_test.dart
@@ -0,0 +1,36 @@
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+class Arg {}
+
+abstract class Base<T> {
+  void foo(T a);
+}
+
+class A extends Base<Arg> {
+  @override
+  void foo(Arg a, [String? b]) {
+    print(a);
+    print(b);
+  }
+}
+
+class B extends A {
+  @override
+  void foo(Arg a, [String? b, int c = 0]) {
+    print(a);
+    print(b);
+    print(c);
+  }
+}
+
+void check(void Function(Arg) closure) {
+  closure(Arg());
+}
+
+void main() {
+  final closure = A().foo;
+  check(closure);
+  B().foo(Arg(), 'b', 3);
+}