Fix crash on invalid entrypoint varying parameter. (#4349)

* Fix crash on invalid entrypoint varying parameter.

* Fix test.

3 files changed, 26 insertions, 2 deletions

diff --git a/source/slang/slang-diagnostic-defs.h b/source/slang/slang-diagnostic-defs.h
index eb7b5b993..f4bad6664 100644
--- a/source/slang/slang-diagnostic-defs.h
+++ b/source/slang/slang-diagnostic-defs.h
@@ -695,6 +695,8 @@ DIAGNOSTIC(39026, Error, matrixLayoutModifierOnNonMatrixType, "matrix layout mod
 
 DIAGNOSTIC(39027, Error, getAttributeAtVertexMustReferToPerVertexInput, "'GetAttributeAtVertex' must reference a vertex input directly, and the vertex input must be decorated with 'pervertex' or 'nointerpolation'.")
 
+DIAGNOSTIC(39028, Error, notValidVaryingParameter, "parameter '$0' is not a valid varying parameter.")
+
 //
 
 // 4xxxx - IL code generation.
diff --git a/source/slang/slang-parameter-binding.cpp b/source/slang/slang-parameter-binding.cpp
index 523ba9287..bce9b5d05 100644
--- a/source/slang/slang-parameter-binding.cpp
+++ b/source/slang/slang-parameter-binding.cpp
@@ -2185,9 +2185,11 @@ static RefPtr<TypeLayout> processEntryPointVaryingParameter(
                     state,
                     fieldVarLayout);
 
-                SLANG_ASSERT(fieldTypeLayout);
-                if(!fieldTypeLayout)
+                if (!fieldTypeLayout)
+                {
+                    getSink(context)->diagnose(field, Diagnostics::notValidVaryingParameter, field);
                     continue;
+                }
                 fieldVarLayout->typeLayout = fieldTypeLayout;
 
                 // The field needs to have offset information stored
@@ -4169,6 +4171,9 @@ ProgramLayout* TargetProgram::getOrCreateLayout(DiagnosticSink* sink)
     if( !m_layout )
     {
         m_layout = generateParameterBindings(this, sink);
+        if (sink->getErrorCount() != 0)
+            return nullptr;
+
         if( m_layout )
         {
             m_irModuleForLayout = createIRModuleForLayout(sink);
diff --git a/tests/bugs/invalid-entrypoint-param.slang b/tests/bugs/invalid-entrypoint-param.slang
new file mode 100644
index 000000000..bafb0fb88
--- /dev/null
+++ b/tests/bugs/invalid-entrypoint-param.slang
@@ -0,0 +1,17 @@
+//TEST:SIMPLE(filecheck=CHECK): -target spirv
+
+// `TT` is not valid for defining a varying entrypoint parameter,
+// and we should diagnose an error.
+
+// CHECK: error 39028
+
+struct TT
+{
+    Texture2D tex;    
+}
+
+[numthreads(1, 1, 1)]
+void f(TT t)
+{
+    return;
+}
\ No newline at end of file