Fix a bug in default ctor synthesizing (#6527)

* Fix a bug in default ctor synthesizing

- This is fix for the implementation bug, when a struct has explicit ctor
  we should not synthesize the default ctor anymore.

- When invoke the synthesized ctor converted from initializer list, we should
  check if the struct is a c-style type if it struct has no synthesized ctor. In this
  case we should report error because it's invalid to use initializer list here.

- The only exception is the unsized array, we still have to fall back to use the
  legacy initializer list logic to initialize the unsized array until we formalize a
  proper solution.

- update test.

3 files changed, 99 insertions, 0 deletions

diff --git a/tests/initializer-list/explicit-ctor-diagnostic.slang b/tests/initializer-list/explicit-ctor-diagnostic.slang
index a9d0e9858..6ce65c016 100644
--- a/tests/initializer-list/explicit-ctor-diagnostic.slang
+++ b/tests/initializer-list/explicit-ctor-diagnostic.slang
@@ -16,4 +16,7 @@ void test()
 {
    // CHECK: error 39999: too many arguments to call (got 2, expected 1)
    ExplicitCtor e = {1, 2}; // error, no ctor matches initializer list.
+
+   // CHECK: error 39999: not enough arguments to call (got 0, expected 1)
+   ExplicitCtor e1 = {};
 }
diff --git a/tests/initializer-list/struct-inherit-diagnostics.slang b/tests/initializer-list/struct-inherit-diagnostics.slang
new file mode 100644
index 000000000..247431570
--- /dev/null
+++ b/tests/initializer-list/struct-inherit-diagnostics.slang
@@ -0,0 +1,39 @@
+//DIAGNOSTIC_TEST:SIMPLE(filecheck=CHECK):
+
+struct DefaultStruct_base
+{
+    int data0;
+    __init()
+    {
+        data0 = 2;
+    }
+};
+
+struct DefaultStruct1 : DefaultStruct_base
+{
+    int data1 = 1;
+};
+
+struct DefaultStruct2 : DefaultStruct_base
+{
+
+};
+
+[numthreads(1, 1, 1)]
+void computeMain(uint3 dispatchThreadID: SV_DispatchThreadID)
+{
+    //CHECK: error 30504: cannot use initializer list for type 'DefaultStruct1'
+    DefaultStruct1 s1 = {};
+
+    //CHECK: error 30504: cannot use initializer list for type 'DefaultStruct1'
+    DefaultStruct1 s2 = {1};
+
+    //CHECK: error 30504: cannot use initializer list for type 'DefaultStruct1'
+    DefaultStruct1 s3 = {1, 2};
+
+    //CHECK: error 30504: cannot use initializer list for type 'DefaultStruct2'
+    DefaultStruct2 s4 = {};
+
+    //CHECK: error 30504: cannot use initializer list for type 'DefaultStruct2'
+    DefaultStruct2 s5 = {1};
+}
diff --git a/tests/initializer-list/struct-inherit.slang b/tests/initializer-list/struct-inherit.slang
new file mode 100644
index 000000000..71487a74f
--- /dev/null
+++ b/tests/initializer-list/struct-inherit.slang
@@ -0,0 +1,57 @@
+//TEST(compute, vulkan):COMPARE_COMPUTE(filecheck-buffer=BUF):-vk -compute -entry computeMain 
+//TEST(compute, vulkan):COMPARE_COMPUTE(filecheck-buffer=BUF):-vk -compute -entry computeMain -emit-spirv-directly
+//TEST(compute, vulkan):COMPARE_COMPUTE(filecheck-buffer=BUF):-cpu -compute -entry computeMain
+//TEST(smoke,compute):COMPARE_COMPUTE(filecheck-buffer=BUF):-dx12 -use-dxil -compute -entry computeMain
+
+//TEST_INPUT:ubuffer(data=[0], stride=4):out,name=outputBuffer
+RWStructuredBuffer<int> outputBuffer;
+
+static int myTwo = 2;
+static int myThree = 1+2;
+
+struct DefaultStruct_base
+{
+    int data0 = 1;
+    int data1;
+
+    __init()
+    {
+        data0 = 2;
+        data1 = 3;
+    }
+};
+
+struct DefaultStruct1 : DefaultStruct_base
+{
+    int data2 = 1;
+    __init()
+    {
+        if (data0 == 2)
+        {
+            data2 = 4;
+        }
+    }
+};
+
+struct DefaultStruct2 : DefaultStruct_base
+{
+    __init()
+    {
+    }
+};
+
+[numthreads(1, 1, 1)]
+void computeMain(uint3 dispatchThreadID: SV_DispatchThreadID)
+{
+    DefaultStruct1 s1;
+    DefaultStruct2 s2;
+
+    // BUF: 1
+    outputBuffer[0] = true
+        && s1.data0 == 2
+        && s1.data1 == 3
+        && s1.data2 == 4
+        && s2.data0 == 2
+        && s2.data1 == 3
+        ;
+}