Fix #23871: identical on consts should be always const

runtime/vm/ast.cc

Index: runtime/vm/ast.cc
diff --git a/runtime/vm/ast.cc b/runtime/vm/ast.cc
index ef224e29aa84a4f1802839e064628e8d73ca5c9a..26618b51f23308e76dfb7051f3f86006c1836b62 100644
--- a/runtime/vm/ast.cc
+++ b/runtime/vm/ast.cc
@@ -229,8 +229,6 @@ const Instance* ComparisonNode::EvalConstExpr() const {
       return NULL;
     case Token::kEQ:
     case Token::kNE:
-    case Token::kEQ_STRICT:
-    case Token::kNE_STRICT:
       // The comparison is a compile time const if both operands are either a
       // number, string, or boolean value (but not necessarily the same type).
       if ((left_val->IsNumber() ||
@@ -244,6 +242,11 @@ const Instance* ComparisonNode::EvalConstExpr() const {
         return &Bool::False();
       }
       return NULL;
+    case Token::kEQ_STRICT:
+    case Token::kNE_STRICT:
+      // identical(a, b) is a compile time const if both operands are
+      // compile time constants, regardless of their type.
+      return &Bool::True();
     default:
       return NULL;
   }