Support cast UnsignedIntegerToUnsignedInteger

Author: ubaidsk

src/libasr/ASR.asdl

@@ -429,6 +429,7 @@ cast_kind
     | IntegerToCharacter
     | LogicalToCharacter
     | UnsignedIntegerToInteger
+    | UnsignedIntegerToUnsignedInteger
     | UnsignedIntegerToReal
     | UnsignedIntegerToLogical
     | IntegerToUnsignedInteger

src/libasr/codegen/asr_to_c_cpp.h

@@ -1754,8 +1754,10 @@ PyMODINIT_FUNC PyInit_lpython_module_)" + fn_name + R"((void) {
                 // src = src;
                 break;
             }
-            case (ASR::cast_kindType::IntegerToInteger) : {
+            case (ASR::cast_kindType::IntegerToInteger) :
+            case (ASR::cast_kindType::UnsignedIntegerToUnsignedInteger) : {
                 // In C++, we do not need to cast int <-> long long explicitly:
+                // we also do not need to cast uint8_t <-> uint32_t explicitly:
                 // src = src;
                 break;
             }

src/libasr/codegen/asr_to_llvm.cpp

@@ -6876,7 +6876,8 @@ class ASRToLLVMVisitor : public ASR::BaseVisitor<ASRToLLVMVisitor>
                 }
                 break;
             }
-            case (ASR::cast_kindType::IntegerToInteger) : {
+            case (ASR::cast_kindType::IntegerToInteger) :
+            case (ASR::cast_kindType::UnsignedIntegerToUnsignedInteger) : {
                 int arg_kind = -1, dest_kind = -1;
                 extract_kinds(x, arg_kind, dest_kind);
                 if( arg_kind > 0 && dest_kind > 0 &&

src/lpython/semantics/python_ast_to_asr.cpp

@@ -72,7 +72,8 @@ namespace CastingUtil {
     const std::map<ASR::ttypeType, ASR::cast_kindType>& kind_rules = {
         {ASR::ttypeType::Complex, ASR::cast_kindType::ComplexToComplex},
         {ASR::ttypeType::Real, ASR::cast_kindType::RealToReal},
-        {ASR::ttypeType::Integer, ASR::cast_kindType::IntegerToInteger}
+        {ASR::ttypeType::Integer, ASR::cast_kindType::IntegerToInteger},
+        {ASR::ttypeType::UnsignedInteger, ASR::cast_kindType::UnsignedIntegerToUnsignedInteger}
     };
 
     int get_type_priority(ASR::ttypeType type) {