Merge pull request #2207 from Shaikh-Ubaid/support_func_with_no_ret_as_callback

Support function with no return type as callback

Author: certik

integration_tests/CMakeLists.txt

@@ -722,6 +722,7 @@ RUN(NAME global_syms_06    LABELS cpython llvm c)
 
 RUN(NAME callback_01       LABELS cpython llvm c)
 RUN(NAME callback_02       LABELS cpython llvm c)
+RUN(NAME callback_03       LABELS cpython llvm c)
 
 # Intrinsic Functions
 RUN(NAME intrinsics_01     LABELS cpython llvm NOFAST) # any

integration_tests/callback_03.py

@@ -0,0 +1,13 @@
+from lpython import i32, Callable
+
+def foo(x : i32) -> None:
+    print(x)
+    assert x == 3
+
+def bar(func : Callable[[i32], None], arg : i32) -> i32:
+    func(arg)
+
+def main0():
+    bar(foo, 3)
+
+main0()

src/lpython/semantics/python_ast_to_asr.cpp

@@ -1703,6 +1703,10 @@ class CommonVisitor : public AST::BaseVisitor<Struct> {
                 abi, is_argument);
         }
 
+        if (AST::is_a<AST::ConstantNone_t>(annotation)) {
+            return nullptr;
+        }
+
         if (AST::is_a<AST::Subscript_t>(annotation)) {
             AST::Subscript_t *s = AST::down_cast<AST::Subscript_t>(&annotation);
             if (AST::is_a<AST::Name_t>(*s->m_value)) {