fix(cpp1): do not pass UDT literal as NTTP

regression-tests/mixed-bugfix-for-literal-as-nttp.cpp2

@@ -0,0 +1,7 @@
+#include <chrono>
+using namespace std::chrono_literals;
+main: () = {
+  [[assert: 10 as i32 == 10]]
+  [[assert: 10LL as i32 == 10]]
+  [[assert: 10s as std::chrono::seconds == 10s]]
+}

regression-tests/test-results/mixed-bugfix-for-literal-as-nttp.cpp

@@ -0,0 +1,27 @@
+
+
+//=== Cpp2 type declarations ====================================================
+
+
+#include "cpp2util.h"
+
+
+
+//=== Cpp2 type definitions and function declarations ===========================
+
+#include <chrono>
+using namespace std::chrono_literals;
+#line 3 "mixed-bugfix-for-literal-as-nttp.cpp2"
+auto main() -> int;
+
+
+//=== Cpp2 function definitions =================================================
+
+
+#line 3 "mixed-bugfix-for-literal-as-nttp.cpp2"
+auto main() -> int{
+  cpp2::Default.expects(cpp2::as_<cpp2::i32, 10>()==10, "");
+  cpp2::Default.expects(cpp2::as_<cpp2::i32, 10LL>()==10, "");
+  cpp2::Default.expects(cpp2::as_<std::chrono::seconds>(10s)==10s, "");
+}
+

regression-tests/test-results/mixed-bugfix-for-literal-as-nttp.cpp2.output

@@ -0,0 +1,2 @@
+mixed-bugfix-for-literal-as-nttp.cpp2... ok (mixed Cpp1/Cpp2, Cpp2 code passes safety checks)
+

source/cppfront.cpp

@@ -3152,16 +3152,20 @@ class cppfront
             && n.expr->get_postfix_expression_node()
             && n.expr->get_postfix_expression_node()->expr
         );
-        if (auto t = n.expr->get_postfix_expression_node()->expr->get_token();
-            t
-            && is_literal(t->type())
-            && t->type() != lexeme::StringLiteral
-            && t->type() != lexeme::FloatLiteral
-            && std::ssize(n.ops) > 0
-            && *n.ops[0].op == "as"
-            )
         {
-            as_on_literal = true;
+            auto& p = n.expr->get_postfix_expression_node()->expr;
+            if (auto t = p->get_token();
+                t
+                && is_literal(t->type())
+                && t->type() != lexeme::StringLiteral
+                && t->type() != lexeme::FloatLiteral
+                && !std::get<primary_expression_node::literal>(p->expr)->user_defined_suffix
+                && std::ssize(n.ops) > 0
+                && *n.ops[0].op == "as"
+                )
+            {
+                as_on_literal = true;
+            }
         }
 
         for (