[Language Server]: Show signature help on generic parameters. (#7913)

* Show signature help on generic parameters.

* Fix.

* Update tests.

* slang-test: make vvl error go through stderr.

* update slang-rhi

* Update slang-rhi

2 files changed, 5 insertions, 2 deletions

diff --git a/tests/diagnostics/extension-visibility.slang b/tests/diagnostics/extension-visibility.slang
index 029b16b86..9923e678d 100644
--- a/tests/diagnostics/extension-visibility.slang
+++ b/tests/diagnostics/extension-visibility.slang
@@ -3,7 +3,7 @@
 // Confirm that visibility of `extensions` is
 // correctly scoped via `import`.
 
-//DIAGNOSTIC_TEST:SIMPLE:
+//DIAGNOSTIC_TEST:SIMPLE(filecheck=CHECK):
 
 import extension_visibility_a;
 
@@ -16,3 +16,5 @@ int shouldntWork(MyThing thing)
 {
 	return helper(thing);
 }
+
+// CHECK: could not specialize generic for arguments of type
\ No newline at end of file
diff --git a/tests/diagnostics/generic-type-inference-fail.slang b/tests/diagnostics/generic-type-inference-fail.slang
index 803c7584c..106570587 100644
--- a/tests/diagnostics/generic-type-inference-fail.slang
+++ b/tests/diagnostics/generic-type-inference-fail.slang
@@ -1,4 +1,4 @@
-//DIAGNOSTIC_TEST:SIMPLE:
+//DIAGNOSTIC_TEST:SIMPLE(filecheck=CHECK):
 
 interface IAssoc
 {
@@ -63,6 +63,7 @@ int test()
     var obj = CreateT<Impl>(2);
     var obj2 = CreateT_Assoc<Impl>(1);
     
+    // CHECK: could not specialize generic for arguments of type
     var obj3 = CreateT_Assoc_Inner(1); // ERROR.
 
     return obj.GetAssoc().Compute() + obj2.Compute() + obj3.Compute();