diff --git a/Cargo.lock b/Cargo.lock
index a8b5ebc71..9ca4e6a0b 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -703,9 +703,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "17392a012ea30ef05a610aa97dfb49496e71c9f676b27879922ea5bdf60d9d3f"
 dependencies = [
  "atty",
- "humantime",
  "log",
- "regex",
  "termcolor",
 ]
 
@@ -915,12 +913,6 @@ version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "79296f72d53a89096cbc9a88c9547ee8dfe793388674620e2207593d370550ac"
 
-[[package]]
-name = "humantime"
-version = "2.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9a3a5bfb195931eeb336b2a7b4d761daec841b97f947d34394601737a7bba5e4"
-
 [[package]]
 name = "indexmap"
 version = "1.6.2"
@@ -1267,17 +1259,6 @@ dependencies = [
  "num-traits",
 ]
 
-[[package]]
-name = "num-iter"
-version = "0.1.42"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b2021c8337a54d21aca0d59a92577a029af9431cb59b909b03252b9c164fad59"
-dependencies = [
- "autocfg",
- "num-integer",
- "num-traits",
-]
-
 [[package]]
 name = "num-rational"
 version = "0.4.0"
@@ -2056,7 +2037,6 @@ dependencies = [
  "num-bigint",
  "num-complex",
  "num-integer",
- "num-iter",
  "num-rational",
  "num-traits",
  "num_cpus",
@@ -2069,7 +2049,6 @@ dependencies = [
  "puruspe",
  "rand 0.8.3",
  "rand_core 0.6.2",
- "regex",
  "result-like",
  "rustc_version_runtime",
  "rustpython-ast",
@@ -2084,7 +2063,6 @@ dependencies = [
  "rustyline",
  "schannel",
  "serde",
- "serde_json",
  "sha-1",
  "sha2",
  "sha3",
diff --git a/Cargo.toml b/Cargo.toml
index 36ab0ded9..a6ca39e48 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -9,6 +9,7 @@ license = "MIT"
 include = ["LICENSE", "Cargo.toml", "src/**/*.rs"]
 
 [workspace]
+resolver = "2"
 members = [
     ".", "ast", "bytecode", "common", "compiler", "compiler/porcelain",
     "derive", "jit", "parser", "vm", "vm/pylib-crate", "wasm/lib",
@@ -26,7 +27,7 @@ ssl = ["rustpython-vm/ssl"]
 
 [dependencies]
 log = "0.4"
-env_logger = "0.8.3"
+env_logger = { version = "0.8", default-features = false, features = ["atty", "termcolor"] }
 clap = "2.33"
 rustpython-compiler = { path = "compiler/porcelain", version = "0.1.1" }
 rustpython-parser = { path = "parser", version = "0.1.1" }
diff --git a/Lib/json/__init__.py b/Lib/json/__init__.py
index 4b7d8897b..1ba8b48bd 100644
--- a/Lib/json/__init__.py
+++ b/Lib/json/__init__.py
@@ -107,11 +107,6 @@ from .decoder import JSONDecoder, JSONDecodeError
 from .encoder import JSONEncoder
 import codecs
 
-_use_serde_json = False
-def use_serde_json(x=True):
-    global _use_serde_json
-    _use_serde_json = x
-
 _default_encoder = JSONEncoder(
     skipkeys=False,
     ensure_ascii=True,
@@ -359,13 +354,6 @@ def loads(s, *, cls=None, object_hook=None, parse_float=None,
     if (cls is None and object_hook is None and
             parse_int is None and parse_float is None and
             parse_constant is None and object_pairs_hook is None and not kw):
-        if _use_serde_json:
-            try:
-                import _serde_json
-            except ImportError:
-                pass
-            else:
-                return _serde_json.decode(s)
         return _default_decoder.decode(s)
     if cls is None:
         cls = JSONDecoder
diff --git a/vm/Cargo.toml b/vm/Cargo.toml
index 0335576bf..d983ba6c3 100644
--- a/vm/Cargo.toml
+++ b/vm/Cargo.toml
@@ -22,7 +22,7 @@ ast = ["rustpython-ast"]
 compiler = ["rustpython-compiler", "rustpython-compiler-core", "ast"]
 parser = ["rustpython-parser", "ast"]
 
-ssl = ["openssl", "openssl-sys", "openssl-probe"]
+ssl = ["openssl", "openssl-sys", "openssl-probe", "foreign-types-shared"]
 
 [dependencies]
 # Crypto:
@@ -38,7 +38,6 @@ num-bigint = { version = "0.4.0", features = ["serde"] }
 num-traits = "0.2.8"
 num-integer = "0.1.41"
 num-rational = "0.4.0"
-num-iter = "0.1.39"
 rand = "0.8"
 rand_core = "0.6"
 getrandom = { version = "0.2", features = ["js"] }
@@ -52,8 +51,6 @@ rustpython-bytecode = { path = "../bytecode", version = "0.1.2" }
 rustpython-jit = { path = "../jit", optional = true, version = "0.1.2" }
 rustpython-pylib = { path = "pylib-crate", optional = true, version = "0.1.0" }
 serde = { version = "1.0.66", features = ["derive"] }
-serde_json = "1.0"
-regex = "1"
 rustc_version_runtime = "0.2.0"
 puruspe = "0.1"
 caseless = "0.2.1"
@@ -73,7 +70,6 @@ paste = "1.0.5"
 base64 = "0.13"
 is-macro = "0.1"
 result-like = "^0.3"
-foreign-types-shared = "0.1"
 num_enum = "0.5"
 bstr = "0.2.12"
 crossbeam-utils = "0.8"
@@ -127,6 +123,7 @@ openssl = { version = "0.10.32", features = ["vendored"], optional = true }
 openssl-sys = { version = "0.9", optional = true }
 openssl-probe = { version = "0.1", optional = true }
 which = "4.0"
+foreign-types-shared = { version = "0.1", optional = true }
 
 [target.'cfg(any(not(target_arch = "wasm32"), target_os = "wasi"))'.dependencies]
 num_cpus = "1"
diff --git a/vm/src/exceptions.rs b/vm/src/exceptions.rs
index 2799a7d26..9ae76fab4 100644
--- a/vm/src/exceptions.rs
+++ b/vm/src/exceptions.rs
@@ -11,9 +11,9 @@ use crate::pyobject::{
     BorrowValue, IntoPyObject, PyClassImpl, PyContext, PyIterable, PyObjectRef, PyRef, PyResult,
     PyValue, TryFromObject, TypeProtocol,
 };
+use crate::sysmodule;
 use crate::types::create_type_with_slots;
 use crate::VirtualMachine;
-use crate::{py_serde, sysmodule};
 
 use crossbeam_utils::atomic::AtomicCell;
 use itertools::Itertools;
@@ -175,7 +175,7 @@ pub fn print_exception(vm: &VirtualMachine, exc: PyBaseExceptionRef) {
             let _ = write_exception(&mut stderr, vm, exc);
         } else {
             eprintln!("{}\nlost sys.stderr", errstr);
-            let _ = write_exception(&mut io::stderr(), vm, exc);
+            let _ = write_exception(&mut py_io::IoWriter(io::stderr()), vm, exc);
         }
     };
     if let Ok(excepthook) = vm.get_attribute(vm.sys_module.clone(), "excepthook") {
@@ -797,7 +797,7 @@ impl serde::Serialize for SerializeException<'_> {
             "context",
             &self.exc.context().as_ref().map(|e| Self::new(self.vm, e)),
         )?;
-        struc.serialize_field("suppress_context", &self.exc.suppress_context.load())?;
+        struc.serialize_field("suppress_context", &self.exc.get_suppress_context())?;
 
         let args = {
             struct Args<'vm>(&'vm VirtualMachine, PyTupleRef);
@@ -807,7 +807,7 @@ impl serde::Serialize for SerializeException<'_> {
                         self.1
                             .borrow_value()
                             .iter()
-                            .map(|arg| py_serde::PyObjectSerializer::new(self.0, arg)),
+                            .map(|arg| crate::py_serde::PyObjectSerializer::new(self.0, arg)),
                     )
                 }
             }
@@ -816,9 +816,9 @@ impl serde::Serialize for SerializeException<'_> {
         struc.serialize_field("args", &args)?;
 
         let rendered = {
-            let mut rendered = Vec::<u8>::new();
+            let mut rendered = String::new();
             write_exception(&mut rendered, self.vm, &self.exc).map_err(S::Error::custom)?;
-            String::from_utf8(rendered).map_err(S::Error::custom)?
+            rendered
         };
         struc.serialize_field("rendered", &rendered)?;
 
diff --git a/vm/src/lib.rs b/vm/src/lib.rs
index 3a92aed60..f7d90bb35 100644
--- a/vm/src/lib.rs
+++ b/vm/src/lib.rs
@@ -59,7 +59,7 @@ mod frozen;
 pub mod function;
 pub mod import;
 pub mod iterator;
-mod py_io;
+pub mod py_io;
 pub mod py_serde;
 pub mod pyobject;
 mod pyobjectrc;
diff --git a/vm/src/py_io.rs b/vm/src/py_io.rs
index 17c007772..0ab7dbef7 100644
--- a/vm/src/py_io.rs
+++ b/vm/src/py_io.rs
@@ -3,20 +3,49 @@ use crate::builtins::pystr::PyStr;
 use crate::exceptions::PyBaseExceptionRef;
 use crate::pyobject::{BorrowValue, PyObjectRef, PyResult};
 use crate::VirtualMachine;
-use std::{fmt, io};
+use std::{fmt, io, ops};
 
 pub trait Write {
     type Error;
     fn write_fmt(&mut self, args: fmt::Arguments) -> Result<(), Self::Error>;
 }
 
-impl<W> Write for W
+#[repr(transparent)]
+pub struct IoWriter<T>(pub T);
+
+impl<T> IoWriter<T> {
+    pub fn from_ref(x: &mut T) -> &mut Self {
+        // SAFETY: IoWriter is repr(transparent) over T
+        unsafe { &mut *(x as *mut T as *mut Self) }
+    }
+}
+
+impl<T> ops::Deref for IoWriter<T> {
+    type Target = T;
+    fn deref(&self) -> &T {
+        &self.0
+    }
+}
+impl<T> ops::DerefMut for IoWriter<T> {
+    fn deref_mut(&mut self) -> &mut T {
+        &mut self.0
+    }
+}
+
+impl<W> Write for IoWriter<W>
 where
     W: io::Write,
 {
     type Error = io::Error;
     fn write_fmt(&mut self, args: fmt::Arguments) -> io::Result<()> {
-        <W as io::Write>::write_fmt(self, args)
+        <W as io::Write>::write_fmt(&mut self.0, args)
+    }
+}
+
+impl Write for String {
+    type Error = fmt::Error;
+    fn write_fmt(&mut self, args: fmt::Arguments) -> fmt::Result {
+        <String as fmt::Write>::write_fmt(self, args)
     }
 }
 
diff --git a/vm/src/stdlib/math.rs b/vm/src/stdlib/math.rs
index fcd100e87..a2cd36cf8 100644
--- a/vm/src/stdlib/math.rs
+++ b/vm/src/stdlib/math.rs
@@ -473,13 +473,20 @@ fn math_fsum(iter: PyIterable<IntoPyFloat>, vm: &VirtualMachine) -> PyResult<f64
 
 fn math_factorial(value: PyIntRef, vm: &VirtualMachine) -> PyResult<BigInt> {
     let value = value.borrow_value();
+    let one = BigInt::one();
     if value.is_negative() {
         return Err(vm.new_value_error("factorial() not defined for negative values".to_owned()));
-    } else if *value <= BigInt::one() {
-        return Ok(BigInt::from(1u64));
+    } else if *value <= one {
+        return Ok(one);
     }
-    let ret: BigInt = num_iter::range_inclusive(BigInt::from(1u64), value.clone()).product();
-    Ok(ret)
+    // start from 2, since we know that value > 1 and 1*2=2
+    let mut current = one + 1;
+    let mut product = BigInt::from(2u8);
+    while current < *value {
+        current += 1;
+        product *= &current;
+    }
+    Ok(product)
 }
 
 fn math_modf(x: IntoPyFloat) -> (f64, f64) {
diff --git a/vm/src/stdlib/mod.rs b/vm/src/stdlib/mod.rs
index 497a219c6..fccbc49df 100644
--- a/vm/src/stdlib/mod.rs
+++ b/vm/src/stdlib/mod.rs
@@ -26,8 +26,8 @@ mod operator;
 mod platform;
 pub(crate) mod pystruct;
 mod random;
-mod re;
-mod serde_json;
+// TODO: maybe make this an extension module, if we ever get those
+// mod re;
 #[cfg(not(target_arch = "wasm32"))]
 pub mod socket;
 mod sre;
@@ -114,9 +114,7 @@ pub fn get_module_inits() -> StdlibMap {
             "math" => math::make_module,
             "_operator" => operator::make_module,
             "_platform" => platform::make_module,
-            "regex_crate" => re::make_module,
             "_random" => random::make_module,
-            "_serde_json" => serde_json::make_module,
             "_sre" => sre::make_module,
             "_string" => string::make_module,
             "_struct" => pystruct::make_module,
diff --git a/vm/src/stdlib/serde_json.rs b/vm/src/stdlib/serde_json.rs
deleted file mode 100644
index 20d4af320..000000000
--- a/vm/src/stdlib/serde_json.rs
+++ /dev/null
@@ -1,39 +0,0 @@
-pub(crate) use _serde_json::make_module;
-
-#[pymodule]
-mod _serde_json {
-    use crate::builtins::pystr::PyStrRef;
-    use crate::common::borrow::BorrowValue;
-    use crate::exceptions::PyBaseExceptionRef;
-    use crate::py_serde;
-    use crate::pyobject::{PyResult, TryFromObject};
-    use crate::VirtualMachine;
-
-    #[pyfunction]
-    fn decode(s: PyStrRef, vm: &VirtualMachine) -> PyResult {
-        let res = (|| -> serde_json::Result<_> {
-            let mut de = serde_json::Deserializer::from_str(s.borrow_value());
-            let res = py_serde::deserialize(vm, &mut de)?;
-            de.end()?;
-            Ok(res)
-        })();
-
-        res.map_err(|err| match json_exception(err, s, vm) {
-            Ok(x) | Err(x) => x,
-        })
-    }
-
-    fn json_exception(
-        err: serde_json::Error,
-        s: PyStrRef,
-        vm: &VirtualMachine,
-    ) -> PyResult<PyBaseExceptionRef> {
-        let decode_error = vm.try_class("json", "JSONDecodeError")?;
-        let from_serde = vm.get_attribute(decode_error.into_object(), "_from_serde")?;
-        let mut err_msg = err.to_string();
-        let pos = err_msg.rfind(" at line ").unwrap();
-        err_msg.truncate(pos);
-        let decode_error = vm.invoke(&from_serde, (err_msg, s, err.line(), err.column()))?;
-        PyBaseExceptionRef::try_from_object(vm, decode_error)
-    }
-}
diff --git a/vm/src/stdlib/thread.rs b/vm/src/stdlib/thread.rs
index ccd14f386..7eece813d 100644
--- a/vm/src/stdlib/thread.rs
+++ b/vm/src/stdlib/thread.rs
@@ -5,12 +5,13 @@ use crate::builtins::tuple::PyTupleRef;
 /// Implementation of the _thread module
 use crate::exceptions::{self, IntoPyException};
 use crate::function::{FuncArgs, KwArgs, OptionalArg};
+use crate::py_io;
 use crate::pyobject::{
     BorrowValue, Either, IdProtocol, ItemProtocol, PyCallable, PyClassImpl, PyObjectRef, PyRef,
     PyResult, PyValue, StaticType, TypeProtocol,
 };
 use crate::slots::{SlotGetattro, SlotSetattro};
-use crate::vm::VirtualMachine;
+use crate::VirtualMachine;
 
 use parking_lot::{
     lock_api::{RawMutex as RawMutexT, RawMutexTimed, RawReentrantMutex},
@@ -255,12 +256,12 @@ fn run_thread(func: PyCallable, args: FuncArgs, vm: &VirtualMachine) {
     if let Err(exc) = func.invoke(args, vm) {
         // TODO: sys.unraisablehook
         let stderr = std::io::stderr();
-        let mut stderr = stderr.lock();
+        let mut stderr = py_io::IoWriter(stderr.lock());
         let repr = vm.to_repr(&func.into_object()).ok();
         let repr = repr
             .as_ref()
             .map_or("<object repr() failed>", |s| s.borrow_value());
-        writeln!(stderr, "Exception ignored in thread started by: {}", repr)
+        writeln!(*stderr, "Exception ignored in thread started by: {}", repr)
             .and_then(|()| exceptions::write_exception(&mut stderr, vm, &exc))
             .ok();
     }
diff --git a/vm/src/vm.rs b/vm/src/vm.rs
index 9acf5e817..fc7a6d242 100644
--- a/vm/src/vm.rs
+++ b/vm/src/vm.rs
@@ -782,9 +782,9 @@ impl VirtualMachine {
                 #[wasm_bindgen(js_namespace = console)]
                 fn error(s: &str);
             }
-            let mut s = Vec::<u8>::new();
+            let mut s = String::new();
             exceptions::write_exception(&mut s, self, &exc).unwrap();
-            error(std::str::from_utf8(&s).unwrap());
+            error(&s);
             panic!("{}; exception backtrace above", msg)
         }
     }