Fix some bad behavior around static methods (#1289)

These are steps towards a fix for the problem of not being able to call a static method as follows:

    SomeType::someMethod();

One problem in the above is that the parser gets confused and parses an (anonynmous!) function declaration. This change doesn't address that problem, but *does* fix the problem that when checking fails to coerce `SomeType::someMethod` into a type it was triggering an unimplemented-feature exception rather than a real error message.

Another problem was that if the above is re-written to try to avoid the parser bug:

    (SomeType::someMethod)();

we end up with a call where the base expression (the callee) is a `ParenExpr` and the code for handling calls wasn't expecting that. Instead, it sent the overload resolution logic into an unimplemented case that was bailing by throwing an arbitrary C++ exception instead of emitting a diagnostic.

This latter issue was fixed in two ways. First, the code path that failed to emit a diagnostic now emits a reasonable one for the unimplemented feature (this still ends up being a fatal compiler error). Second, we properly handle the case of trying to call a `ParenExpr` by unwrapping it and using the base expression instead, so that `(<func>)(<args>)` is always treated the same as `<func>(<args>)`.

2 files changed, 38 insertions, 0 deletions

diff --git a/tests/bugs/static-method.slang b/tests/bugs/static-method.slang
new file mode 100644
index 000000000..dfb13b4a8
--- /dev/null
+++ b/tests/bugs/static-method.slang
@@ -0,0 +1,34 @@
+// static-method.slang
+
+//TEST(compute):COMPARE_COMPUTE_EX:-slang -compute
+
+struct S
+{
+	static void doThing(in out int x, int y)
+	{
+		x += y;
+	}
+}
+
+//TEST_INPUT:ubuffer(data=[0 0 0 0], stride=4):out
+RWStructuredBuffer<int> outputBuffer : register(u0);
+
+int test(int t)
+{
+	// TODO: This case is currently being mis-handled by the parser
+//	S::doThing(t, 0x10);
+
+	(S::doThing(t, 0x200));
+
+	(S::doThing)(t, 0x4000);
+
+	return t;
+}
+
+[numthreads(4)]
+void computeMain(uint3 tid : SV_DispatchThreadID)
+{
+	int val = tid.x;
+	val = test(val);
+	outputBuffer[tid.x] = val;
+}
diff --git a/tests/bugs/static-method.slang.expected.txt b/tests/bugs/static-method.slang.expected.txt
new file mode 100644
index 000000000..017c3bd20
--- /dev/null
+++ b/tests/bugs/static-method.slang.expected.txt
@@ -0,0 +1,4 @@
+4200
+4201
+4202
+4203