4 files changed, 35 insertions, 3 deletions
diff --git a/tests/features/test_concurrency_suite.zc b/tests/features/test_concurrency_suite.zc
index 836594d..aa7512a 100644
--- a/tests/features/test_concurrency_suite.zc
+++ b/tests/features/test_concurrency_suite.zc
@@ -59,7 +59,7 @@ test "test_thread" {
     c.val = 0;
     c.lock = Mutex::new();
     
-    const N = 10000;
+    def N = 10000;
     
     var t1_res = Thread::spawn(fn() {
         for (var i=0; i<N; ++i) {
diff --git a/tests/features/test_const_def.zc b/tests/features/test_const_def.zc
new file mode 100644
index 0000000..b104196
--- /dev/null
+++ b/tests/features/test_const_def.zc
@@ -0,0 +1,32 @@
+
+test "def_constants" {
+    def PI = 3.14159;
+    def MAX = 100;
+    
+    assert(MAX == 100, "def constant value mismatch");
+    // PI check (float) - exact match might be tricky but 3.14159 is literal
+    
+    var x = MAX; 
+    assert(x == 100, "Assign from def");
+}
+
+test "def_scoping" {
+    def VAL = 1;
+    {
+        def VAL = 2; // Shadowing
+        assert(VAL == 2, "Shadowed def");
+    }
+    assert(VAL == 1, "Original def preserved");
+}
+
+test "const_type_qualifier" {
+    var x: const int = 10;
+    assert(x == 10, "const Var init");
+    
+    // Address of const var should be allowed
+    var p: const int* = &x; 
+    assert(*p == 10, "Pointer to const var");
+}
+
+// Note: Negative tests (compilation failures) are hard to test in this harness currently
+// but we verified the logic in parser_expr.c
diff --git a/tests/features/test_match_ref.zc b/tests/features/test_match_ref.zc
index cdd0835..0442dc7 100644
--- a/tests/features/test_match_ref.zc
+++ b/tests/features/test_match_ref.zc
@@ -50,7 +50,7 @@ enum Test {
 }
 
 test "match ref binding concrete" {
-    const t = Test::ONE(Hello{ world: 123 });
+    var t = Test::ONE(Hello{ world: 123 });
 
     var val = 0;
     match t {
diff --git a/tests/features/test_operators_suite.zc b/tests/features/test_operators_suite.zc
index 68b73fe..cf0f4c2 100644
--- a/tests/features/test_operators_suite.zc
+++ b/tests/features/test_operators_suite.zc
@@ -93,7 +93,7 @@ test "test_operator_overloading" {
     f1 |= f2; 
     "Result bits: {f1.bits} (Expected 5)";
     
-    const MAX_LIMIT = 100;
+    def MAX_LIMIT = 100;
 }
 
 test "test_extended_overloading" {