From 160111a0e27c9325ddfc49a53fbb82d3c6f06c90 Mon Sep 17 00:00:00 2001
From: jsmall-nvidia <jsmall@nvidia.com>
Date: Wed, 9 Feb 2022 11:26:04 -0500
Subject: Generic experiments (#2119)

* #include an absolute path didn't work - because paths were taken to always be relative.

* Small fixes.
Added compiler crash with generic defined in a function.
Added enum-flags test that works (by limiting backing type to int), and using __EnumType constraint.

* Add comment about crash.

* Disable crashing test.
---
 tests/experiments/generic/enum-int-flags-2.slang   | 45 ++++++++++++++++++++++
 tests/experiments/generic/equality-3.slang         |  4 +-
 tests/experiments/generic/equality-5.slang         |  4 +-
 .../experiments/generic/generic-in-function.slang  | 30 +++++++++++++++
 4 files changed, 79 insertions(+), 4 deletions(-)
 create mode 100644 tests/experiments/generic/enum-int-flags-2.slang
 create mode 100644 tests/experiments/generic/generic-in-function.slang

diff --git a/tests/experiments/generic/enum-int-flags-2.slang b/tests/experiments/generic/enum-int-flags-2.slang
new file mode 100644
index 000000000..c5283fb7e
--- /dev/null
+++ b/tests/experiments/generic/enum-int-flags-2.slang
@@ -0,0 +1,45 @@
+//DISABLE_TEST(compute):COMPARE_COMPUTE_EX:-slang -compute -shaderobj
+
+/* A test to use generics to treat an enum as a set. 
+Here we simplify previous example, by not allowing the backing type be 
+a specialization parameter (and just use int).
+
+Moreover here E is constrained to __EnumType.
+
+Works
+*/
+
+//TEST_INPUT:ubuffer(data=[0 0 0 0], stride=4):out,name outputBuffer
+RWStructuredBuffer<float> outputBuffer;
+
+enum Enum
+{
+    A = 0x1,
+    B = 0x2, 
+    C = 0x4,
+};
+
+__generic<E : __EnumType>
+struct Flags
+{
+    [mutating] void set(E e) { value |= (int)e; }
+    bool isSet(E e) { return (((int)e) & value) != 0; }
+    int value = 0;
+};
+
+[numthreads(4, 1, 1)]
+void computeMain(uint3 dispatchThreadID : SV_DispatchThreadID)
+{
+    int index = dispatchThreadID.x;
+    
+    Flags<Enum> flags;
+
+    if (index & 1)
+    {
+        flags.set(Enum::A);
+    }
+    bool isASet = flags.isSet(Enum::A);
+   
+	outputBuffer[index] = isASet ? 2 : 1;
+}
+
diff --git a/tests/experiments/generic/equality-3.slang b/tests/experiments/generic/equality-3.slang
index e5e42aedf..033b90415 100644
--- a/tests/experiments/generic/equality-3.slang
+++ b/tests/experiments/generic/equality-3.slang
@@ -2,7 +2,9 @@
 
 /* A test for equality around interface types
 
-This style is discussed in the documentation here:
+This style is discussed in the documentation here (on This type):
+
+https://github.com/shader-slang/slang/blob/master/docs/user-guide/04-interfaces-generics.md
 
 Still has limitiation that it only works for an an implementation of an interface.  
  */
diff --git a/tests/experiments/generic/equality-5.slang b/tests/experiments/generic/equality-5.slang
index 41cadbbfc..0f2932d41 100644
--- a/tests/experiments/generic/equality-5.slang
+++ b/tests/experiments/generic/equality-5.slang
@@ -2,11 +2,9 @@
 
 /* A test for equality around interface types
 
-This is an attempt to get the *outside* impl of equality to work. The simple case does, but just to throw 
-a spanner in the works, lets mix in some inheritance. 
+This is an attempt to get the *outside* impl of equality to work. The simple case does, but just to throw a spanner in the works, lets mix in some inheritance. 
 
 An issue here (perhaps) is that this will compile - the isEqual implementation will just slice and probably not do what the implementer expected.
-    
  */
 
 //TEST_INPUT:ubuffer(data=[0 0 0 0], stride=4):out,name outputBuffer
diff --git a/tests/experiments/generic/generic-in-function.slang b/tests/experiments/generic/generic-in-function.slang
new file mode 100644
index 000000000..7a45d43de
--- /dev/null
+++ b/tests/experiments/generic/generic-in-function.slang
@@ -0,0 +1,30 @@
+//DISABLE_TEST(compute):COMPARE_COMPUTE_EX:-slang -compute -shaderobj
+
+/* It appears the use of a generic defined within a function appears to trigger a crash
+
+
+```
+void Type::accept(ITypeVisitor* visitor, void* extra)
+```
+
+As this is nullptr.
+*/
+
+RWStructuredBuffer<float> outputBuffer;
+
+int doThing()
+{    
+	int getValue<let N : int>() { return N; }
+    
+    return getValue<10>();
+}
+
+[numthreads(4, 1, 1)]
+void computeMain(uint3 dispatchThreadID : SV_DispatchThreadID)
+{
+	uint tid = dispatchThreadID.x;
+
+	float inVal = float(tid);
+
+	outputBuffer[tid] = doThing();
+}
-- 
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