fix[ux]: fold keccak and sha256 of constant hexbytes (#4536)

This commit allows `keccak` and `sha256` of a constant hexbytes value
to be folded.

Author: tserg

tests/functional/builtins/codegen/test_keccak256.py

@@ -111,3 +111,17 @@ def foo() -> bytes32:
     """
     c = get_contract(code)
     assert c.foo() == keccak(str_val.encode())
+
+
+def test_hash_constant_hexbytes(get_contract, keccak):
+    hexbytes_val = "67363d3d37363d34f03d5260086018f3"
+    code = f"""
+FOO: constant(Bytes[16]) = x"{hexbytes_val}"
+BAR: constant(bytes32) = keccak256(FOO)
+@external
+def foo() -> bytes32:
+    x: bytes32 = BAR
+    return x
+    """
+    c = get_contract(code)
+    assert c.foo() == keccak(bytes.fromhex(hexbytes_val))

tests/functional/builtins/codegen/test_sha256.py

@@ -103,3 +103,17 @@ def foo() -> bytes32:
     """
     c = get_contract(code)
     assert c.foo() == hashlib.sha256(str_val.encode()).digest()
+
+
+def test_sha256_constant_hexbytes(get_contract, keccak):
+    hexbytes_val = "67363d3d37363d34f03d5260086018f3"
+    code = f"""
+FOO: constant(Bytes[16]) = x"{hexbytes_val}"
+BAR: constant(bytes32) = sha256(FOO)
+@external
+def foo() -> bytes32:
+    x: bytes32 = BAR
+    return x
+    """
+    c = get_contract(code)
+    assert c.foo() == hashlib.sha256(bytes.fromhex(hexbytes_val)).digest()

vyper/builtins/functions.py

@@ -594,7 +594,7 @@ class Keccak256(BuiltinFunctionT):
     def _try_fold(self, node):
         validate_call_args(node, 1)
         value = node.args[0].get_folded_value()
-        if isinstance(value, vy_ast.Bytes):
+        if isinstance(value, (vy_ast.Bytes, vy_ast.HexBytes)):
             value = value.value
         elif isinstance(value, vy_ast.Str):
             value = value.value.encode()
@@ -641,7 +641,7 @@ class Sha256(BuiltinFunctionT):
     def _try_fold(self, node):
         validate_call_args(node, 1)
         value = node.args[0].get_folded_value()
-        if isinstance(value, vy_ast.Bytes):
+        if isinstance(value, (vy_ast.Bytes, vy_ast.HexBytes)):
             value = value.value
         elif isinstance(value, vy_ast.Str):
             value = value.value.encode()