feat: no unnecessary encode utf8 (#686)

resources/test/fixtures/U012.py

@@ -0,0 +1,52 @@
+# ASCII literals should be replaced by a bytes literal
+"foo".encode("utf-8")  # b"foo"
+"foo".encode("u8")  # b"foo"
+"foo".encode()  # b"foo"
+"foo".encode("UTF8")  # b"foo"
+U"foo".encode("utf-8")  # b"foo"
+"foo".encode(encoding="utf-8")  # b"foo"
+"""
+Lorem
+
+Ipsum
+""".encode(
+    "utf-8"
+)
+# b"""
+# Lorem
+#
+# Ipsum
+# """
+
+# `encode` on variables should not be processed.
+string = "hello there"
+string.encode("utf-8")
+
+bar = "bar"
+f"foo{bar}".encode("utf-8")  # f"foo{bar}".encode()
+encoding = "latin"
+"foo".encode(encoding)
+f"foo{bar}".encode(encoding)
+
+# `encode` with custom args and kwargs should not be processed.
+"foo".encode("utf-8", errors="replace")
+"foo".encode("utf-8", "replace")
+"foo".encode(errors="replace")
+"foo".encode(encoding="utf-8", errors="replace")
+
+# `encode` with custom args and kwargs on unicode should not be processed.
+"unicode text©".encode("utf-8", errors="replace")
+"unicode text©".encode("utf-8", "replace")
+"unicode text©".encode(errors="replace")
+"unicode text©".encode(encoding="utf-8", errors="replace")
+
+# Unicode literals should only be stripped of default encoding.
+"unicode text©".encode("utf-8")  # "unicode text©".encode()
+"unicode text©".encode()
+"unicode text©".encode(encoding="UTF8")  # "unicode text©".encode()
+
+r"fo\o".encode("utf-8")  # br"fo\o"
+u"foo".encode("utf-8")  # b"foo"
+R"fo\o".encode("utf-8")  # br"fo\o"
+U"foo".encode("utf-8")  # b"foo"
+print("foo".encode())  # print(b"foo")