Fix crash when private ctor is used for coercion. (#7858)

* Fix crash when private ctor is used for coercion.

* Fix tests.

* Fix.

* Fix test error.

3 files changed, 63 insertions, 0 deletions

diff --git a/tests/language-server/private-ctor-call/bsdfs.slang b/tests/language-server/private-ctor-call/bsdfs.slang
new file mode 100644
index 000000000..ff50ab352
--- /dev/null
+++ b/tests/language-server/private-ctor-call/bsdfs.slang
@@ -0,0 +1,28 @@
+module bsdfs;
+__include lambert_diffuse_btdf;
+
+public struct BSDFContext
+{
+    float iorI;  ///< IOR from incidence medium
+    float iorT;  ///< IOR trom transmission medium
+    bool inited; ///< Flag to indicate if the struct was initialized
+
+    __init(float iorI_, float iorT_)
+    {
+        iorI = iorI_;
+        iorT = iorT_;
+        inited = true;
+    }
+
+    __init()
+    {
+        iorI = 1.f;
+        iorT = 1.f;
+        inited = false;
+    }
+}
+
+public interface IBSDF
+{
+    public float3 eval(const float3 wi, const float3 wo, BSDFContext bc);
+}
diff --git a/tests/language-server/private-ctor-call/lambert_diffuse_btdf.slang b/tests/language-server/private-ctor-call/lambert_diffuse_btdf.slang
new file mode 100644
index 000000000..82f766da4
--- /dev/null
+++ b/tests/language-server/private-ctor-call/lambert_diffuse_btdf.slang
@@ -0,0 +1,22 @@
+implementing bsdfs;
+public struct LambertDiffuseBTDF : IBSDF, IDifferentiable
+{
+    float3 albedo = {}; ///< Diffuse albedo.
+#if 0
+    public __init(float3 albedo_)
+#else
+    __init(float3 albedo_)
+#endif
+    {
+        this.albedo = albedo_;
+    }
+
+    [Differentiable]
+    public float3 eval(const float3 wi, const float3 wo, BSDFContext bc)
+    {
+        if (min(wi.z, -wo.z) < 1e-6f)
+            return float3(0.f);
+
+        return (1.0 / 3.1415) * albedo * -wo.z;
+    }
+}
diff --git a/tests/language-server/private-ctor-call/test-main.slang b/tests/language-server/private-ctor-call/test-main.slang
new file mode 100644
index 000000000..2074c3b8d
--- /dev/null
+++ b/tests/language-server/private-ctor-call/test-main.slang
@@ -0,0 +1,13 @@
+//TEST:LANG_SERVER(filecheck=CHECK):
+
+module "test-main";
+
+import bsdfs;
+
+LambertDiffuseBTDF createTranslucent(float3 color, float3 normal)
+{
+//HOVER:10,21
+    return LambertDiffuseBTDF( color );
+}
+
+//CHECK: LambertDiffuseBTDF.init