Ensure generic constraints are checked before inner extension. (#7685)

* Ensure generic constraints are checked before inner extension.

* Add warning for non-standard generic extension.

* Fix tests.

* Fix test.

* Ban interface types from equality constraints.

* Fix.

3 files changed, 55 insertions, 0 deletions

diff --git a/tests/language-feature/extensions/generic-extension-2.slang b/tests/language-feature/extensions/generic-extension-2.slang
index 2728a73d6..d56455e3d 100644
--- a/tests/language-feature/extensions/generic-extension-2.slang
+++ b/tests/language-feature/extensions/generic-extension-2.slang
@@ -1,4 +1,6 @@
 //TEST(compute):COMPARE_COMPUTE(filecheck-buffer=CHECK): -shaderobj
+
+#pragma warning(disable:30856)
 interface IFoo<T>
 {
     T getFirst();    
diff --git a/tests/language-feature/extensions/generic-extension-5.slang b/tests/language-feature/extensions/generic-extension-5.slang
new file mode 100644
index 000000000..e6466d614
--- /dev/null
+++ b/tests/language-feature/extensions/generic-extension-5.slang
@@ -0,0 +1,52 @@
+//TEST:INTERPRET(filecheck=CHECK):
+interface IGen<A>
+{
+    associatedtype TB;
+    TB getVal();
+}
+
+struct Foo1<A> : IGen<A>
+{
+    typealias TB = int;
+    int val = 0;
+    TB getVal()
+    {
+       return val; 
+    }
+}
+
+struct Foo2<A> : IGen<A>
+{
+    typealias TB = int;
+    int val = 0;
+    TB getVal()
+    {
+       return val; 
+    }
+}
+
+struct Logic<A1, C1 : IGen<A1>, C2 : IGen<A1>>
+{
+    int val = 0;
+}
+
+extension<A, C1, C2> Logic<A, C1, C2>
+    where C1 : IGen<A>
+    where C2 : IGen<A>
+    where C1.TB == C2.TB
+{
+    [mutating]
+    void setVal(int dataIn)
+    {
+        val = dataIn;
+    }
+}
+
+void main()
+{
+    Logic<int, Foo1<int>, Foo2<int>> logic;
+    logic.setVal(42);
+    int result = logic.val;
+    printf("Result: %d\n", result);
+    // CHECK: Result: 42
+}
\ No newline at end of file
diff --git a/tests/language-feature/overloaded-subscript.slang b/tests/language-feature/overloaded-subscript.slang
index 68ad1111a..e928e97ec 100644
--- a/tests/language-feature/overloaded-subscript.slang
+++ b/tests/language-feature/overloaded-subscript.slang
@@ -13,6 +13,7 @@ interface IRWBuf<T> : IBuf<T>
     void write(int x, T v);
 }
 
+#pragma warning(disable:30856)
 extension<T, U : IBuf<T>> U
 {
     __subscript(int x) -> T { get { return read(x); } }