Disallow only resources in constant buffers in parameterblocks on metal (#6342)

* Neaten metal parameter block checking

* Disallow only resources in constant buffers in parameterblocks on metal

closes https://github.com/shader-slang/slang/issues/6200

* add unit test for metal parameterblock cbuffer

---------

Co-authored-by: Yong He <yonghe@outlook.com>

1 files changed, 20 insertions, 7 deletions

diff --git a/tests/diagnostics/nested-constant-buffer-in-parameter-block.slang b/tests/diagnostics/nested-constant-buffer-in-parameter-block.slang
index eb9ecdd14..9fb83f034 100644
--- a/tests/diagnostics/nested-constant-buffer-in-parameter-block.slang
+++ b/tests/diagnostics/nested-constant-buffer-in-parameter-block.slang
@@ -1,20 +1,33 @@
 //TEST:SIMPLE(filecheck=CHECK): -target metal
 
+struct T
+{
+    RWStructuredBuffer<int> buf;
+}
+    
+struct U
+{
+    ConstantBuffer<T> t;
+}
+
 struct S
 {
-    // CHECK-DAG: ([[# @LINE+1]]): error 56100:
-    ConstantBuffer<int> cb;
+    ConstantBuffer<RWStructuredBuffer<int>> cb;
 }
 
-ParameterBlock<S> s;
+// CHECK-DAG: ([[# @LINE+1]]): error 56101:
+ParameterBlock<S> s1;
+
+// CHECK-DAG: ([[# @LINE+1]]): error 56101:
+ParameterBlock<U> s2;
 
-// CHECK-DAG: ([[# @LINE+1]]): error 56100:
-ParameterBlock<ConstantBuffer<int>> s2;
+// CHECK-DAG: ([[# @LINE+1]]): error 56101:
+ParameterBlock<ConstantBuffer<RWStructuredBuffer<int>>> s3;
 
 RWStructuredBuffer<int> outputBuffer;
 
 [numthreads(1,1,1)]
 void kernelMain()
 {
-    outputBuffer[0] = s.cb + s2;
-}
\ No newline at end of file
+    outputBuffer[0] = s1.cb[0] + s2.t.buf[0] + s3[0];
+}