fixes #27586, prefer context type in generic inference

pkg/dev_compiler/lib/src/compiler/code_generator.dart

Index: pkg/dev_compiler/lib/src/compiler/code_generator.dart
diff --git a/pkg/dev_compiler/lib/src/compiler/code_generator.dart b/pkg/dev_compiler/lib/src/compiler/code_generator.dart
index deb528af8607798c265d03bb753f4b880d096c10..331531cdb2bacc1790e161755f2e7e59799a90fd 100644
--- a/pkg/dev_compiler/lib/src/compiler/code_generator.dart
+++ b/pkg/dev_compiler/lib/src/compiler/code_generator.dart
@@ -5409,10 +5409,11 @@ class CodeGenerator extends GeneralizingAstVisitor
     return result is JS.Node ? annotate(result, node) : result;
   }
 
-  List/*<T>*/ _visitList/*<T extends AstNode>*/(Iterable/*<T>*/ nodes) {
+  // TODO(jmesserly): we should make sure this only returns JS AST nodes.
+  List/*<R>*/ _visitList/*<T extends AstNode, R>*/(Iterable/*<T>*/ nodes) {
     if (nodes == null) return null;
-    var result = /*<T>*/ [];
-    for (var node in nodes) result.add(_visit(node) as dynamic/*=T*/);
+    var result = /*<R>*/ [];
+    for (var node in nodes) result.add(_visit(node) as dynamic/*=R*/);
     return result;
   }