diff --git a/crates/parser/src/conversion.rs b/crates/parser/src/conversion.rs
index f15c9ae..19b7586 100644
--- a/crates/parser/src/conversion.rs
+++ b/crates/parser/src/conversion.rs
@@ -113,13 +113,12 @@ pub(crate) fn convert_memarg(memarg: wasmparser::MemArg) -> MemArg {
 }
 
 pub fn process_operators<'a>(
-    offset: usize,
+    mut offset: usize,
     ops: impl Iterator<Item = Result<wasmparser::Operator<'a>, wasmparser::BinaryReaderError>>,
     mut validator: FuncValidator<ValidatorResources>,
 ) -> Result<Box<[Instruction]>> {
     let mut instructions = Vec::new();
 
-    let mut offset = offset.into();
     for op in ops {
         let op = op?;
         validator.op(offset, &op)?;
diff --git a/crates/tinywasm/Cargo.toml b/crates/tinywasm/Cargo.toml
index dd7da94..1865614 100644
--- a/crates/tinywasm/Cargo.toml
+++ b/crates/tinywasm/Cargo.toml
@@ -27,4 +27,3 @@ default=["std", "parser", "logging"]
 logging=["log", "tinywasm-types/logging", "tinywasm-parser?/logging"]
 std=["tinywasm-parser?/std", "tinywasm-types/std"]
 parser=["tinywasm-parser"]
-nightly=[]
diff --git a/crates/tinywasm/src/error.rs b/crates/tinywasm/src/error.rs
index 926a9bc..dc53106 100644
--- a/crates/tinywasm/src/error.rs
+++ b/crates/tinywasm/src/error.rs
@@ -71,6 +71,7 @@ impl Display for Error {
     }
 }
 
+#[cfg(any(feature = "std", all(not(feature = "std"), nightly)))]
 impl crate::std::error::Error for Error {}
 
 #[cfg(feature = "parser")]
diff --git a/crates/tinywasm/src/lib.rs b/crates/tinywasm/src/lib.rs
index 8abf280..179cca3 100644
--- a/crates/tinywasm/src/lib.rs
+++ b/crates/tinywasm/src/lib.rs
@@ -8,7 +8,7 @@
     )
 ))]
 #![warn(missing_docs, missing_debug_implementations, rust_2018_idioms, unreachable_pub)]
-#![cfg_attr(feature = "nightly", feature(error_in_core))]
+#![cfg_attr(nightly, feature(error_in_core))]
 
 //! A tiny WebAssembly Runtime written in Rust
 //!
@@ -56,14 +56,11 @@
 //! - `parser` (default): Enables the `tinywasm_parser` crate for parsing WebAssembly modules.
 //!
 //! ## No-std support
-//! TinyWasm supports `no_std` environments by disabling the `std` feature. This removes
-//! support for parsing from files and streams, but otherwise the API is the same.
-//! Additionally, you must use a nightly compiler as TinyWasm uses the `error_in_core` feature
-//! and have a `GlobalAlloc` implementation for allocating memory.
-
-// compiler error when using no_std without nightly
-#[cfg(all(not(feature = "std"), not(nightly)))]
-const _: () = { compile_error!("`nightly` feature is required for `no_std`") };
+//! TinyWasm supports `no_std` environments by disabling the `std` feature and registering
+//! a custom allocator. This removes support for parsing from files and streams,
+//! but otherwise the API is the same.
+//!
+//! Additionally, if you want proper error types, you must use a `nightly` compiler.
 
 mod std;
 extern crate alloc;
diff --git a/crates/tinywasm/src/std.rs b/crates/tinywasm/src/std.rs
index c31de8f..b77675b 100644
--- a/crates/tinywasm/src/std.rs
+++ b/crates/tinywasm/src/std.rs
@@ -13,6 +13,6 @@ pub(crate) mod error {
     #[cfg(feature = "std")]
     pub(crate) use std::error::Error;
 
-    #[cfg(not(feature = "std"))]
+    #[cfg(all(not(feature = "std"), nightly))]
     pub(crate) use core::error::Error;
 }
diff --git a/crates/tinywasm/tests/mvp.rs b/crates/tinywasm/tests/mvp.rs
index dacffe3..87a36d8 100644
--- a/crates/tinywasm/tests/mvp.rs
+++ b/crates/tinywasm/tests/mvp.rs
@@ -18,12 +18,10 @@ fn parse_module(mut module: wast::core::Module) -> Result<TinyWasmModule, Error>
 
 #[test]
 #[ignore]
-fn test_mvp() {
+fn test_mvp() -> Result<()> {
     let mut test_suite = TestSuite::new();
 
     wasm_testsuite::MVP_TESTS.iter().for_each(|group| {
-        println!("test: {}", group);
-
         let test_group = test_suite.test_group(group);
 
         let wast = wasm_testsuite::get_test_wast(group).expect("failed to get test wast");
@@ -59,11 +57,9 @@ fn test_mvp() {
                 AssertMalformed {
                     span,
                     module: QuoteWat::Wat(wast::Wat::Module(module)),
-                    message,
+                    message: _,
                 } => {
-                    println!("  assert_malformed: {}", message);
                     let res = std::panic::catch_unwind(|| parse_module(module).map(|_| ()));
-
                     test_group.add_result(
                         &format!("{}-malformed", name),
                         span,
@@ -85,9 +81,11 @@ fn test_mvp() {
     });
 
     if test_suite.failed() {
-        panic!("failed one or more tests: {:#?}", test_suite);
+        eprintln!("\n\nfailed one or more tests:\n{:#?}", test_suite);
+        Err(Error::Other("failed one or more tests".to_string()))
     } else {
-        println!("passed all tests: {:#?}", test_suite);
+        println!("\n\npassed all tests:\n{:#?}", test_suite);
+        Ok(())
     }
 }
 
@@ -169,11 +167,11 @@ impl TestGroup {
     }
 
     fn add_result(&mut self, name: &str, span: wast::token::Span, result: Result<()>) {
-        self.tests.insert(name.to_string(), TestCase { result, span });
+        self.tests.insert(name.to_string(), TestCase { result, _span: span });
     }
 }
 
 struct TestCase {
     result: Result<()>,
-    span: wast::token::Span,
+    _span: wast::token::Span,
 }
diff --git a/crates/wasm-testsuite/lib.rs b/crates/wasm-testsuite/lib.rs
index 50ff48f..7e6afb4 100644
--- a/crates/wasm-testsuite/lib.rs
+++ b/crates/wasm-testsuite/lib.rs
@@ -39,7 +39,7 @@ pub const V2_DRAFT_1_TESTS: &[&str] = &["address.wast","align.wast","binary-leb1
 
 /// Get all test file names and their contents.
 pub fn get_tests_wast(include_proposals: &[String]) -> impl Iterator<Item = (String, Cow<'static, [u8]>)> {
-    get_tests(&include_proposals)
+    get_tests(include_proposals)
         .filter_map(|name| Some((name.clone(), get_test_wast(&name)?)))
         .map(|(name, data)| (name, Cow::Owned(data.to_vec())))
 }