Fix more strong mode errors in analyzer

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 48490141f235f045e2c72d3876bd718fd4be8067..17cef9bf9b74c9ef8e8d2176938166d3917fc871 100644
--- a/pkg/analyzer/lib/src/generated/resolver.dart
+++ b/pkg/analyzer/lib/src/generated/resolver.dart
@@ -7543,8 +7543,10 @@ class ResolverVisitor extends ScopedVisitor {
 
     // Same number of type formals. Instantiate the function type so its
     // parameter and return type are in terms of the surrounding context.
-    return fnType.instantiate(
-        typeParameters.map((t) => t.name.staticElement.type).toList());
+    return fnType.instantiate(typeParameters
+        .map((TypeParameter t) =>
+            (t.name.staticElement as TypeParameterElement).type)
+        .toList());
   }
 
   /**