Expand _AssertionError._evaluateAssertion in the frontend

runtime/vm/parser.cc

Index: runtime/vm/parser.cc
diff --git a/runtime/vm/parser.cc b/runtime/vm/parser.cc
index e75d86d82291669b6fd6f85271c8a1f9288e38b4..d4544829e36a596bd721f1dcb8e916d829bc9165 100644
--- a/runtime/vm/parser.cc
+++ b/runtime/vm/parser.cc
@@ -9249,13 +9249,24 @@ AstNode* Parser::ParseAssertStatement(bool is_const) {
   ExpectToken(Token::kRPAREN);
 
   if (!is_const) {
-    // Check for assertion condition being a function if not const.
-    ArgumentListNode* arguments = new (Z) ArgumentListNode(condition_pos);
-    arguments->Add(condition);
-    condition = MakeStaticCall(
-        Symbols::AssertionError(),
-        Library::PrivateCoreLibName(Symbols::EvaluateAssertion()), arguments);
+    if (condition->IsClosureNode()) {
+      // We always have to invoke a closure node.
+      InstanceCallNode* invoke_condition =
+          new (Z) InstanceCallNode(condition_pos, condition, Symbols::Call(),
+                                   new (Z) ArgumentListNode(condition_pos));
+      condition = invoke_condition;
+    } else if (condition->IsComparisonNode() || condition->IsUnaryOpNode()) {
+      // Cannot be a function, skip type test and invocation.
+    } else {
+      // Check for assertion condition being a function if not const.
+      ArgumentListNode* arguments = new (Z) ArgumentListNode(condition_pos);
+      arguments->Add(condition);
+      condition = MakeStaticCall(
+          Symbols::AssertionError(),
+          Library::PrivateCoreLibName(Symbols::EvaluateAssertion()), arguments);
+    }
   }
+
   AstNode* not_condition =
       new (Z) UnaryOpNode(condition_pos, Token::kNOT, condition);