diff --git a/src/analyze.cpp b/src/analyze.cpp
index a20c2091c..e0539df10 100644
--- a/src/analyze.cpp
+++ b/src/analyze.cpp
@@ -1224,6 +1224,9 @@ ZigType *get_fn_type(CodeGen *g, FnTypeId *fn_type_id) {
 
         fn_type->data.fn.gen_param_count = gen_param_types.length;
 
+        for (size_t i = 0; i < gen_param_types.length; i += 1) {
+            assert(gen_param_types.items[i] != nullptr);
+        }
         fn_type->data.fn.raw_type_ref = LLVMFunctionType(gen_return_type->type_ref,
                 gen_param_types.items, (unsigned int)gen_param_types.length, fn_type_id->is_var_args);
         fn_type->type_ref = LLVMPointerType(fn_type->data.fn.raw_type_ref, 0);
diff --git a/src/ir.cpp b/src/ir.cpp
index 30f40b3a1..77b34e755 100644
--- a/src/ir.cpp
+++ b/src/ir.cpp
@@ -19643,7 +19643,7 @@ static ZigType *ir_analyze_instruction_fn_proto(IrAnalyze *ira, IrInstructionFnP
                 return ira->codegen->builtin_types.entry_invalid;
             if (type_requires_comptime(param_type)) {
                 if (!calling_convention_allows_zig_types(fn_type_id.cc)) {
-                    ir_add_error(ira, &instruction->base,
+                    ir_add_error(ira, param_type_value,
                         buf_sprintf("parameter of type '%s' not allowed in function with calling convention '%s'",
                             buf_ptr(&param_type->name), calling_convention_name(fn_type_id.cc)));
                     return ira->codegen->builtin_types.entry_invalid;
@@ -19654,6 +19654,12 @@ static ZigType *ir_analyze_instruction_fn_proto(IrAnalyze *ira, IrInstructionFnP
                 out_val->data.x_type = get_generic_fn_type(ira->codegen, &fn_type_id);
                 return ira->codegen->builtin_types.entry_type;
             }
+            if (!type_has_bits(param_type) && !calling_convention_allows_zig_types(fn_type_id.cc)) {
+                ir_add_error(ira, param_type_value,
+                    buf_sprintf("parameter of type '%s' has 0 bits; not allowed in function with calling convention '%s'",
+                        buf_ptr(&param_type->name), calling_convention_name(fn_type_id.cc)));
+                return ira->codegen->builtin_types.entry_invalid;
+            }
             param_info->type = param_type;
         }
 
diff --git a/test/compile_errors.zig b/test/compile_errors.zig
index 185ca6297..dda45a589 100644
--- a/test/compile_errors.zig
+++ b/test/compile_errors.zig
@@ -1291,6 +1291,7 @@ pub fn addCases(cases: *tests.CompileErrorContext) void {
         \\
         \\extern fn bar(x: *void) void { }
     ,
+        ".tmp_source.zig:1:30: error: parameter of type '*void' has 0 bits; not allowed in function with calling convention 'ccc'",
         ".tmp_source.zig:7:18: error: parameter of type '*void' has 0 bits; not allowed in function with calling convention 'ccc'",
     );