Band-aid fix for issue #24191.

pkg/analyzer/lib/src/generated/resolver.dart

Index: pkg/analyzer/lib/src/generated/resolver.dart
diff --git a/pkg/analyzer/lib/src/generated/resolver.dart b/pkg/analyzer/lib/src/generated/resolver.dart
index 6fe292ae7bb080e3ab0050adf1156820a35d321f..0119fa2200b44fcf33b37fbb8ef79877dd3db56b 100644
--- a/pkg/analyzer/lib/src/generated/resolver.dart
+++ b/pkg/analyzer/lib/src/generated/resolver.dart
@@ -11265,7 +11265,11 @@ class ResolverVisitor extends ScopedVisitor {
           return null;
         }
         DartType eventType = onDataParameters[0].type;
-        if (eventType.element == streamType.typeParameters[0]) {
+        // TODO(paulberry): checking that typeParameters.isNotEmpty is a
+        // band-aid fix for dartbug.com/24191.  Figure out what the correct
+        // logic should be.
+        if (streamType.typeParameters.isNotEmpty &&
+            eventType.element == streamType.typeParameters[0]) {
           return streamType.typeArguments[0];
         }
       }