fix: provide better error message for unsupported types in ARC4 conta…

…iners

src/puya/awst/wtypes.py

@@ -335,20 +335,30 @@ def _m_validator(self, _attribute: object, m: int) -> None:
             raise CodeError("Precision must be between 1 and 160 inclusive", self.source_location)
 
 
-def _required_arc4_wtypes(wtypes: Iterable[WType]) -> tuple[ARC4Type, ...]:
-    result = []
-    for wtype in wtypes:
-        if not isinstance(wtype, ARC4Type):
-            raise CodeError(f"expected ARC4 type: {wtype}")
-        result.append(wtype)
-    return tuple(result)
+def _tuple_requires_arc4_types(wtypes: Iterable[WType], node: WType) -> tuple[ARC4Type, ...]:
+    return tuple(
+        _narrow_arc4_wtype(wtype, "tuple", wtype.source_location or node.source_location)
+        for wtype in wtypes
+    )
+
+
+def _array_requires_arc4_type(wtype: WType, node: WType) -> ARC4Type:
+    return _narrow_arc4_wtype(wtype, "array", wtype.source_location or node.source_location)
+
+
+def _narrow_arc4_wtype(wtype: WType, context: str, loc: SourceLocation | None) -> ARC4Type:
+    if isinstance(wtype, ARC4Type):
+        return wtype
+    raise CodeError(f"{wtype} is not supported in an ARC4 {context}", loc)
 
 
 @typing.final
 @attrs.frozen(kw_only=True)
 class ARC4Tuple(ARC4Type):
     source_location: SourceLocation | None = attrs.field(default=None, eq=False)
-    types: tuple[ARC4Type, ...] = attrs.field(converter=_required_arc4_wtypes)
+    types: tuple[ARC4Type, ...] = attrs.field(
+        converter=attrs.Converter(_tuple_requires_arc4_types, takes_self=True)  # type: ignore[misc, call-overload]
+    )
     name: str = attrs.field(init=False)
     arc4_name: str = attrs.field(init=False, eq=False)
     immutable: bool = attrs.field(init=False)
@@ -387,15 +397,11 @@ def _is_arc4_encodeable_tuple(
     )
 
 
-def _expect_arc4_type(wtype: WType) -> ARC4Type:
-    if not isinstance(wtype, ARC4Type):
-        raise CodeError(f"expected ARC4 type: {wtype}")
-    return wtype
-
-
 @attrs.frozen(kw_only=True)
 class ARC4Array(ARC4Type):
-    element_type: ARC4Type = attrs.field(converter=_expect_arc4_type)
+    element_type: ARC4Type = attrs.field(
+        converter=attrs.Converter(_array_requires_arc4_type, takes_self=True)  # type: ignore[misc, call-overload]
+    )
     native_type: WType | None = None
     immutable: bool = False
 

tests/test_expected_output/arc4.test

@@ -65,8 +65,8 @@ def wrong_arg_type3() -> None:
 
 @subroutine
 def wrong_arg_type4() -> None:
-    arc4.emit("Event(string,uint8)", Event(arc4.String("a"), arc4.UInt8(1))) ## E: expected type algopy.arc4.String, got type test_emit_errors.Event \
-                                                                             ## E: expected 2 ABI arguments, got 1
+    arc4.emit("Event(string,uint8)", Event(arc4.String("a"), arc4.UInt8(1))) ## E: expected 2 ABI arguments, got 1 \
+                                                                             ## E: expected type algopy.arc4.String, got type test_emit_errors.Event
 
 @subroutine
 def wrong_arg_type5() -> None:
@@ -655,3 +655,14 @@ def c() -> None:
 @subroutine
 def d() -> None:
     assert not arc4.DynamicArray[int]() ## E: Python literals of type int cannot be used as runtime values
+
+## case: abimethod_reference_type_in_tuple
+from algopy import *
+
+class ARC4Reference(arc4.ARC4Contract):
+    @arc4.abimethod()
+    def test(self,
+        arg: tuple[Account, Asset], ## E: account is not supported in an ARC4 tuple
+        arg2: tuple[Account, Application],
+    ) -> None:
+        pass