Fix exact-match witness synthesis for static functions (#6204)

* fix non-static methods when trying to synthesize method requirement witness

* add tests

* update test

* improve test

---------

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

3 files changed, 78 insertions, 0 deletions

diff --git a/tests/language-feature/interfaces/non-static-method-implemented-by-static.slang b/tests/language-feature/interfaces/non-static-method-implemented-by-static.slang
new file mode 100644
index 000000000..9c243af94
--- /dev/null
+++ b/tests/language-feature/interfaces/non-static-method-implemented-by-static.slang
@@ -0,0 +1,45 @@
+//TEST(compute):COMPARE_COMPUTE_EX:-vk -compute  -output-using-type
+
+//TEST_INPUT: set outputBuffer = out ubuffer(data=[0 0 0 0 0], stride=4);
+RWStructuredBuffer<int> outputBuffer;
+
+interface Base
+{
+    int getValue();
+    int getValue(float a);
+}
+
+struct Impl1 : Base
+{
+    // This is static and allowed to implement interface's non-static method.
+    static int getValue() { return 5; }
+    int getValue(float a) { return int(a) + 5; }
+}
+
+struct Impl2 : Base
+{
+    // This is static with one default parameter and allowed to implement interface's non-static method.
+    static int getValue(int a = 3) { return a + 5; }
+    int getValue(float a) { return int(a) + 5; }
+}
+
+int callGet<T : Base>(T t)
+{
+    return t.getValue();
+}
+
+[numthreads(1, 1, 1)]
+void computeMain()
+{
+    Impl1 impl1;
+    Impl2 impl2;
+
+    uint index = 0;
+
+    outputBuffer[index++] = Impl1::getValue();
+    outputBuffer[index++] = callGet(impl1);
+
+    outputBuffer[index++] = Impl2::getValue();
+    outputBuffer[index++] = callGet(impl2);
+    outputBuffer[index++] = impl2.getValue(5);
+}
diff --git a/tests/language-feature/interfaces/non-static-method-implemented-by-static.slang.expected.txt b/tests/language-feature/interfaces/non-static-method-implemented-by-static.slang.expected.txt
new file mode 100644
index 000000000..42d1e8278
--- /dev/null
+++ b/tests/language-feature/interfaces/non-static-method-implemented-by-static.slang.expected.txt
@@ -0,0 +1,6 @@
+type: int32_t
+5
+5
+8
+8
+10
diff --git a/tests/language-feature/interfaces/static-method-not-implemented.slang b/tests/language-feature/interfaces/static-method-not-implemented.slang
new file mode 100644
index 000000000..1d46c1be6
--- /dev/null
+++ b/tests/language-feature/interfaces/static-method-not-implemented.slang
@@ -0,0 +1,27 @@
+//DIAGNOSTIC_TEST:SIMPLE(filecheck=CHECK): -target spirv
+
+interface Base
+{
+    static int getValue();
+}
+
+struct Impl : Base
+{
+    // This is not static and not allowed to implement the interface's static method.
+    // CHECK: error 38105: member 'getValue' does not match interface requirement
+    int getValue() { return 5; }
+}
+
+int callGet<Foo : Base>()
+{
+    return Foo::getValue();
+}
+
+RWStructuredBuffer<int> result;
+
+[numthreads(1, 1, 1)]
+void computeMain()
+{
+    result[0] = callGet<Impl>();
+}
+