1 files changed, 51 insertions, 0 deletions
diff --git a/tests/current-bugs/generic/mutating-interface.slang b/tests/current-bugs/generic/mutating-interface.slang
new file mode 100644
index 000000000..2198b56b2
--- /dev/null
+++ b/tests/current-bugs/generic/mutating-interface.slang
@@ -0,0 +1,51 @@
+//DISABLE_TEST(compute):COMPARE_COMPUTE_EX:-slang -compute -shaderobj
+
+/* A test using interfaces with mutation.
+
+Doesn't work because
+
+.slang(18): error 30050: mutating method 'lock' cannot be called on an immutable value
+    lockable.lock();
+    
+If that section is removed we get on `doThing(count)`
+
+.slang(31): error 30047: argument passed to parameter '0' must be l-value.
+
+Which perhaps means an inteface cannot be used as a lvalue?
+*/
+
+//TEST_INPUT:ubuffer(data=[0 0 0 0], stride=4):out,name outputBuffer
+RWStructuredBuffer<int> outputBuffer;
+
+interface ILockable
+{
+    [mutating] void lock();
+    [mutating] void unlock();
+};
+
+struct IntCount : ILockable
+{
+    [mutating] void lock() { count ++; }
+    [mutating] void unlock() { --count; }
+    int count = 0;
+};
+
+int doThing(inout ILockable lockable)
+{
+    lockable.lock();
+    // do something...
+    
+    lockable.unlock();
+    return 0;
+}
+
+[numthreads(4, 1, 1)]
+void computeMain(uint3 dispatchThreadID : SV_DispatchThreadID)
+{    
+    int index = dispatchThreadID.x;
+    
+    IntCount count;
+    doThing(count);
+    
+    outputBuffer[dispatchThreadID.x] = count.count;
+}
+\ No newline at end of file