diff --git a/examples/callback-guest/callback-guest.rs b/examples/callback-guest/callback-guest.rs
index 129ad05c8ac..aec238ca199 100644
--- a/examples/callback-guest/callback-guest.rs
+++ b/examples/callback-guest/callback-guest.rs
@@ -4,7 +4,6 @@ extern "C" {
     fn host_callback() -> u32;
 }
 
-#[no_mangle]
 fn test_callback() -> u32 {
     42
 }
diff --git a/examples/callback-guest/callback-guest.wasm b/examples/callback-guest/callback-guest.wasm
index 05558297595..3595bcd592c 100755
Binary files a/examples/callback-guest/callback-guest.wasm and b/examples/callback-guest/callback-guest.wasm differ
diff --git a/lib/clif-backend/src/signal/mod.rs b/lib/clif-backend/src/signal/mod.rs
index cb6e147b1a7..19e71c70021 100644
--- a/lib/clif-backend/src/signal/mod.rs
+++ b/lib/clif-backend/src/signal/mod.rs
@@ -4,9 +4,10 @@ use crate::{
     trampoline::Trampolines,
 };
 use libc::c_void;
-use std::{any::Any, cell::Cell, ptr::NonNull, sync::Arc};
+use std::{cell::Cell, ptr::NonNull, sync::Arc};
 use wasmer_runtime_core::{
     backend::RunnableModule,
+    error::RuntimeError,
     module::ModuleInfo,
     typed_func::{Trampoline, Wasm},
     types::{LocalFuncIndex, SigIndex},
@@ -26,11 +27,9 @@ pub use self::unix::*;
 pub use self::windows::*;
 
 thread_local! {
-    pub static TRAP_EARLY_DATA: Cell<Option<Box<dyn Any + Send>>> = Cell::new(None);
+    pub static TRAP_EARLY_DATA: Cell<Option<RuntimeError>> = Cell::new(None);
 }
 
-pub struct CallProtError(pub Box<dyn Any + Send>);
-
 pub struct Caller {
     handler_data: HandlerData,
     trampolines: Arc<Trampolines>,
@@ -63,7 +62,7 @@ impl RunnableModule for Caller {
             func: NonNull<vm::Func>,
             args: *const u64,
             rets: *mut u64,
-            error_out: *mut Option<Box<dyn Any + Send>>,
+            error_out: *mut Option<RuntimeError>,
             invoke_env: Option<NonNull<c_void>>,
         ) -> bool {
             let handler_data = &*invoke_env.unwrap().cast().as_ptr();
@@ -80,7 +79,10 @@ impl RunnableModule for Caller {
 
             match res {
                 Err(err) => {
-                    *error_out = Some(err.0);
+                    // probably makes the most sense to actually do a translation here to a
+                    // a generic type defined in runtime-core
+                    // TODO: figure out _this_ error return story
+                    *error_out = Some(err.into());
                     false
                 }
                 Ok(()) => true,
@@ -101,7 +103,7 @@ impl RunnableModule for Caller {
         })
     }
 
-    unsafe fn do_early_trap(&self, data: Box<dyn Any + Send>) -> ! {
+    unsafe fn do_early_trap(&self, data: RuntimeError) -> ! {
         TRAP_EARLY_DATA.with(|cell| cell.set(Some(data)));
         trigger_trap()
     }
diff --git a/lib/clif-backend/src/signal/unix.rs b/lib/clif-backend/src/signal/unix.rs
index 98571cbbff3..965359e354f 100644
--- a/lib/clif-backend/src/signal/unix.rs
+++ b/lib/clif-backend/src/signal/unix.rs
@@ -10,7 +10,7 @@
 //! unless you have memory unsafety elsewhere in your code.
 //!
 use crate::relocation::{TrapCode, TrapData};
-use crate::signal::{CallProtError, HandlerData};
+use crate::signal::HandlerData;
 use libc::{c_int, c_void, siginfo_t};
 use nix::sys::signal::{
     sigaction, SaFlags, SigAction, SigHandler, SigSet, Signal, SIGBUS, SIGFPE, SIGILL, SIGSEGV,
@@ -19,6 +19,7 @@ use std::cell::{Cell, UnsafeCell};
 use std::ptr;
 use std::sync::Once;
 use wasmer_runtime_core::backend::ExceptionCode;
+use wasmer_runtime_core::error::InvokeError;
 
 extern "C" fn signal_trap_handler(
     signum: ::nix::libc::c_int,
@@ -65,7 +66,7 @@ pub unsafe fn trigger_trap() -> ! {
 pub fn call_protected<T>(
     handler_data: &HandlerData,
     f: impl FnOnce() -> T,
-) -> Result<T, CallProtError> {
+) -> Result<T, InvokeError> {
     unsafe {
         let jmp_buf = SETJMP_BUFFER.with(|buf| buf.get());
         let prev_jmp_buf = *jmp_buf;
@@ -79,16 +80,12 @@ pub fn call_protected<T>(
             *jmp_buf = prev_jmp_buf;
 
             if let Some(data) = super::TRAP_EARLY_DATA.with(|cell| cell.replace(None)) {
-                Err(CallProtError(data))
+                Err(InvokeError::EarlyTrap(Box::new(data)))
             } else {
                 let (faulting_addr, inst_ptr) = CAUGHT_ADDRESSES.with(|cell| cell.get());
 
-                if let Some(TrapData {
-                    trapcode,
-                    srcloc: _,
-                }) = handler_data.lookup(inst_ptr)
-                {
-                    Err(CallProtError(Box::new(match Signal::from_c_int(signum) {
+                if let Some(TrapData { trapcode, srcloc }) = handler_data.lookup(inst_ptr) {
+                    let code = match Signal::from_c_int(signum) {
                         Ok(SIGILL) => match trapcode {
                             TrapCode::StackOverflow => ExceptionCode::MemoryOutOfBounds,
                             TrapCode::HeapOutOfBounds => ExceptionCode::MemoryOutOfBounds,
@@ -101,9 +98,10 @@ pub fn call_protected<T>(
                             TrapCode::BadConversionToInteger => ExceptionCode::IllegalArithmetic,
                             TrapCode::UnreachableCodeReached => ExceptionCode::Unreachable,
                             _ => {
-                                return Err(CallProtError(Box::new(
-                                    "unknown clif trap code".to_string(),
-                                )))
+                                return Err(InvokeError::UnknownTrapCode {
+                                    trap_code: format!("{:?}", trapcode),
+                                    srcloc,
+                                })
                             }
                         },
                         Ok(SIGSEGV) | Ok(SIGBUS) => ExceptionCode::MemoryOutOfBounds,
@@ -112,7 +110,8 @@ pub fn call_protected<T>(
                             "ExceptionCode::Unknown signal:{:?}",
                             Signal::from_c_int(signum)
                         ),
-                    })))
+                    };
+                    Err(InvokeError::TrapCode { srcloc, code })
                 } else {
                     let signal = match Signal::from_c_int(signum) {
                         Ok(SIGFPE) => "floating-point exception",
@@ -123,8 +122,10 @@ pub fn call_protected<T>(
                         _ => "unknown trapped signal",
                     };
                     // When the trap-handler is fully implemented, this will return more information.
-                    let s = format!("unknown trap at {:p} - {}", faulting_addr, signal);
-                    Err(CallProtError(Box::new(s)))
+                    Err(InvokeError::UnknownTrap {
+                        address: faulting_addr as usize,
+                        signal,
+                    })
                 }
             }
         } else {
diff --git a/lib/clif-backend/src/signal/windows.rs b/lib/clif-backend/src/signal/windows.rs
index 7d3e81d695f..1228db9a7c5 100644
--- a/lib/clif-backend/src/signal/windows.rs
+++ b/lib/clif-backend/src/signal/windows.rs
@@ -1,6 +1,6 @@
 use crate::{
     relocation::{TrapCode, TrapData},
-    signal::{CallProtError, HandlerData},
+    signal::HandlerData,
 };
 use std::{
     cell::Cell,
@@ -9,6 +9,7 @@ use std::{
 };
 use wasmer_runtime_core::{
     backend::ExceptionCode,
+    error::InvokeError,
     typed_func::Trampoline,
     vm::{Ctx, Func},
 };
@@ -32,6 +33,34 @@ thread_local! {
     pub static CURRENT_EXECUTABLE_BUFFER: Cell<*const c_void> = Cell::new(ptr::null());
 }
 
+fn get_signal_name(code: DWORD) -> &'static str {
+    match code {
+        EXCEPTION_FLT_DENORMAL_OPERAND
+        | EXCEPTION_FLT_DIVIDE_BY_ZERO
+        | EXCEPTION_FLT_INEXACT_RESULT
+        | EXCEPTION_FLT_INVALID_OPERATION
+        | EXCEPTION_FLT_OVERFLOW
+        | EXCEPTION_FLT_STACK_CHECK
+        | EXCEPTION_FLT_UNDERFLOW => "floating-point exception",
+        EXCEPTION_ILLEGAL_INSTRUCTION => "illegal instruction",
+        EXCEPTION_ACCESS_VIOLATION => "segmentation violation",
+        EXCEPTION_DATATYPE_MISALIGNMENT => "datatype misalignment",
+        EXCEPTION_BREAKPOINT => "breakpoint",
+        EXCEPTION_SINGLE_STEP => "single step",
+        EXCEPTION_ARRAY_BOUNDS_EXCEEDED => "array bounds exceeded",
+        EXCEPTION_INT_DIVIDE_BY_ZERO => "int div by zero",
+        EXCEPTION_INT_OVERFLOW => "int overflow",
+        EXCEPTION_PRIV_INSTRUCTION => "priv instruction",
+        EXCEPTION_IN_PAGE_ERROR => "in page error",
+        EXCEPTION_NONCONTINUABLE_EXCEPTION => "non continuable exception",
+        EXCEPTION_STACK_OVERFLOW => "stack overflow",
+        EXCEPTION_GUARD_PAGE => "guard page",
+        EXCEPTION_INVALID_HANDLE => "invalid handle",
+        EXCEPTION_POSSIBLE_DEADLOCK => "possible deadlock",
+        _ => "unknown exception code",
+    }
+}
+
 pub fn call_protected(
     handler_data: &HandlerData,
     trampoline: Trampoline,
@@ -39,7 +68,7 @@ pub fn call_protected(
     func: NonNull<Func>,
     param_vec: *const u64,
     return_vec: *mut u64,
-) -> Result<(), CallProtError> {
+) -> Result<(), InvokeError> {
     // TODO: trap early
     // user code error
     //    if let Some(msg) = super::TRAP_EARLY_DATA.with(|cell| cell.replace(None)) {
@@ -58,12 +87,8 @@ pub fn call_protected(
         instruction_pointer,
     } = result.unwrap_err();
 
-    if let Some(TrapData {
-        trapcode,
-        srcloc: _,
-    }) = handler_data.lookup(instruction_pointer as _)
-    {
-        Err(CallProtError(Box::new(match code as DWORD {
+    if let Some(TrapData { trapcode, srcloc }) = handler_data.lookup(instruction_pointer as _) {
+        let exception_code = match code as DWORD {
             EXCEPTION_ACCESS_VIOLATION => ExceptionCode::MemoryOutOfBounds,
             EXCEPTION_ILLEGAL_INSTRUCTION => match trapcode {
                 TrapCode::BadSignature => ExceptionCode::IncorrectCallIndirectSignature,
@@ -71,51 +96,36 @@ pub fn call_protected(
                 TrapCode::HeapOutOfBounds => ExceptionCode::MemoryOutOfBounds,
                 TrapCode::TableOutOfBounds => ExceptionCode::CallIndirectOOB,
                 TrapCode::UnreachableCodeReached => ExceptionCode::Unreachable,
-                _ => return Err(CallProtError(Box::new("unknown trap code".to_string()))),
+                _ => {
+                    return Err(InvokeError::UnknownTrapCode {
+                        trap_code: format!("{}", code as DWORD),
+                        srcloc,
+                    })
+                }
             },
             EXCEPTION_STACK_OVERFLOW => ExceptionCode::MemoryOutOfBounds,
             EXCEPTION_INT_DIVIDE_BY_ZERO | EXCEPTION_INT_OVERFLOW => {
                 ExceptionCode::IllegalArithmetic
             }
             _ => {
-                return Err(CallProtError(Box::new(
-                    "unknown exception code".to_string(),
-                )))
+                let signal = get_signal_name(code as DWORD);
+                return Err(InvokeError::UnknownTrap {
+                    address: exception_address as usize,
+                    signal,
+                });
             }
-        })))
-    } else {
-        let signal = match code as DWORD {
-            EXCEPTION_FLT_DENORMAL_OPERAND
-            | EXCEPTION_FLT_DIVIDE_BY_ZERO
-            | EXCEPTION_FLT_INEXACT_RESULT
-            | EXCEPTION_FLT_INVALID_OPERATION
-            | EXCEPTION_FLT_OVERFLOW
-            | EXCEPTION_FLT_STACK_CHECK
-            | EXCEPTION_FLT_UNDERFLOW => "floating-point exception",
-            EXCEPTION_ILLEGAL_INSTRUCTION => "illegal instruction",
-            EXCEPTION_ACCESS_VIOLATION => "segmentation violation",
-            EXCEPTION_DATATYPE_MISALIGNMENT => "datatype misalignment",
-            EXCEPTION_BREAKPOINT => "breakpoint",
-            EXCEPTION_SINGLE_STEP => "single step",
-            EXCEPTION_ARRAY_BOUNDS_EXCEEDED => "array bounds exceeded",
-            EXCEPTION_INT_DIVIDE_BY_ZERO => "int div by zero",
-            EXCEPTION_INT_OVERFLOW => "int overflow",
-            EXCEPTION_PRIV_INSTRUCTION => "priv instruction",
-            EXCEPTION_IN_PAGE_ERROR => "in page error",
-            EXCEPTION_NONCONTINUABLE_EXCEPTION => "non continuable exception",
-            EXCEPTION_STACK_OVERFLOW => "stack overflow",
-            EXCEPTION_GUARD_PAGE => "guard page",
-            EXCEPTION_INVALID_HANDLE => "invalid handle",
-            EXCEPTION_POSSIBLE_DEADLOCK => "possible deadlock",
-            _ => "unknown exception code",
         };
+        return Err(InvokeError::TrapCode {
+            srcloc,
+            code: exception_code,
+        });
+    } else {
+        let signal = get_signal_name(code as DWORD);
 
-        let s = format!(
-            "unhandled trap at {:x} - code #{:x}: {}",
-            exception_address, code, signal,
-        );
-
-        Err(CallProtError(Box::new(s)))
+        Err(InvokeError::UnknownTrap {
+            address: exception_address as usize,
+            signal,
+        })
     }
 }
 
diff --git a/lib/llvm-backend/cpp/object_loader.cpp b/lib/llvm-backend/cpp/object_loader.cpp
index c4fc6d93628..5688f9d81df 100644
--- a/lib/llvm-backend/cpp/object_loader.cpp
+++ b/lib/llvm-backend/cpp/object_loader.cpp
@@ -13,7 +13,7 @@ MemoryManager::~MemoryManager() {
   callbacks.dealloc_memory(read_section.base, read_section.size);
   callbacks.dealloc_memory(readwrite_section.base, readwrite_section.size);
 }
-void unwinding_setjmp(jmp_buf stack_out, void (*func)(void *), void *userdata) {
+void unwinding_setjmp(jmp_buf &stack_out, void (*func)(void *), void *userdata) {
   if (setjmp(stack_out)) {
 
   } else {
diff --git a/lib/llvm-backend/cpp/object_loader.hh b/lib/llvm-backend/cpp/object_loader.hh
index 53bd2b0df85..a20a93a48cc 100644
--- a/lib/llvm-backend/cpp/object_loader.hh
+++ b/lib/llvm-backend/cpp/object_loader.hh
@@ -49,9 +49,7 @@ typedef struct {
   visit_fde_t visit_fde;
 } callbacks_t;
 
-typedef struct {
-  size_t data, vtable;
-} box_any_t;
+using runtime_error_t = void*;
 
 enum WasmTrapType {
   Unreachable = 0,
@@ -65,6 +63,8 @@ enum WasmTrapType {
 
 extern "C" void callback_trampoline(void *, void *);
 
+extern "C" void copy_runtime_error(runtime_error_t src, runtime_error_t dst);
+
 struct MemoryManager : llvm::RuntimeDyld::MemoryManager {
 public:
   MemoryManager(callbacks_t callbacks) : callbacks(callbacks) {}
@@ -121,7 +121,7 @@ private:
 
 struct WasmErrorSink {
   WasmTrapType *trap_out;
-  box_any_t *user_error;
+  runtime_error_t user_error;
 };
 
 struct WasmException : std::exception {
@@ -149,17 +149,19 @@ public:
 
 struct UserException : UncatchableException {
 public:
-  UserException(size_t data, size_t vtable) : error_data({data, vtable}) {}
+  UserException(size_t data) {
+      error_data = reinterpret_cast<runtime_error_t>(data);
+  }
 
   virtual std::string description() const noexcept override {
     return "user exception";
   }
 
-  // The parts of a `Box<dyn Any>`.
-  box_any_t error_data;
+  // The pointer to `Option<RuntimeError>`.
+  runtime_error_t error_data;
 
   virtual void write_error(WasmErrorSink &out) const noexcept override {
-    *out.user_error = error_data;
+    copy_runtime_error(error_data, out.user_error);
   }
 };
 
@@ -274,10 +276,10 @@ result_t module_load(const uint8_t *mem_ptr, size_t mem_size,
 
 void module_delete(WasmModule *module) { delete module; }
 
-// Throw a fat pointer that's assumed to be `*mut dyn Any` on the rust
+// Throw a pointer that's assumed to be `*mut Option<RuntimeError>` on the rust
 // side.
-[[noreturn]] void throw_any(size_t data, size_t vtable) {
-  unsafe_unwind(new UserException(data, vtable));
+[[noreturn]] void throw_runtime_error(size_t data) {
+  unsafe_unwind(new UserException(data));
 }
 
 // Throw a pointer that's assumed to be codegen::BreakpointHandler on the
@@ -288,7 +290,7 @@ void module_delete(WasmModule *module) { delete module; }
 
 bool cxx_invoke_trampoline(trampoline_t trampoline, void *ctx, void *func,
                        void *params, void *results, WasmTrapType *trap_out,
-                       box_any_t *user_error, void *invoke_env) noexcept {
+                       runtime_error_t user_error, void *invoke_env) noexcept {
   try {
     catch_unwind([trampoline, ctx, func, params, results]() {
       trampoline(ctx, func, params, results);
diff --git a/lib/llvm-backend/src/backend.rs b/lib/llvm-backend/src/backend.rs
index a2ac15a940c..b1540712c91 100644
--- a/lib/llvm-backend/src/backend.rs
+++ b/lib/llvm-backend/src/backend.rs
@@ -11,7 +11,6 @@ use inkwell::{
 };
 use libc::c_char;
 use std::{
-    any::Any,
     cell::RefCell,
     ffi::{c_void, CString},
     mem,
@@ -27,6 +26,7 @@ use wasmer_runtime_core::{
         CacheGen, ExceptionCode, RunnableModule,
     },
     cache::Error as CacheError,
+    error::{InvokeError, RuntimeError},
     module::ModuleInfo,
     state::ModuleStateMap,
     structures::TypedIndex,
@@ -52,11 +52,9 @@ extern "C" {
     fn throw_trap(ty: i32) -> !;
     fn throw_breakpoint(ty: i64) -> !;
 
-    /// This should be the same as spliting up the fat pointer into two arguments,
-    /// but this is cleaner, I think?
     #[cfg_attr(nightly, unwind(allowed))]
     #[allow(improper_ctypes)]
-    fn throw_any(data: *mut dyn Any) -> !;
+    fn throw_runtime_error(data: *mut Option<RuntimeError>) -> !;
 
     #[allow(improper_ctypes)]
     fn cxx_invoke_trampoline(
@@ -66,11 +64,21 @@ extern "C" {
         params: *const u64,
         results: *mut u64,
         trap_out: *mut i32,
-        error_out: *mut Option<Box<dyn Any + Send>>,
+        error_out: *mut Option<RuntimeError>,
         invoke_env: Option<NonNull<c_void>>,
     ) -> bool;
 }
 
+#[no_mangle]
+pub unsafe extern "C" fn copy_runtime_error(
+    src: *mut Option<RuntimeError>,
+    dst: *mut Option<RuntimeError>,
+) {
+    assert_eq!(src as usize % mem::align_of::<Option<RuntimeError>>(), 0);
+    assert_eq!(dst as usize % mem::align_of::<Option<RuntimeError>>(), 0);
+    ptr::copy::<Option<RuntimeError>>(src, dst, 1);
+}
+
 /// `invoke_trampoline` is a wrapper around `cxx_invoke_trampoline`, for fixing up the obsoleted
 /// `trap_out` in the C++ part.
 unsafe extern "C" fn invoke_trampoline(
@@ -79,7 +87,7 @@ unsafe extern "C" fn invoke_trampoline(
     func_ptr: NonNull<vm::Func>,
     params: *const u64,
     results: *mut u64,
-    error_out: *mut Option<Box<dyn Any + Send>>,
+    error_out: *mut Option<RuntimeError>,
     invoke_env: Option<NonNull<c_void>>,
 ) -> bool {
     let mut trap_out: i32 = -1;
@@ -95,15 +103,22 @@ unsafe extern "C" fn invoke_trampoline(
     );
     // Translate trap code if an error occurred.
     if !ret && (*error_out).is_none() && trap_out != -1 {
-        *error_out = Some(Box::new(match trap_out {
-            0 => ExceptionCode::Unreachable,
-            1 => ExceptionCode::IncorrectCallIndirectSignature,
-            2 => ExceptionCode::MemoryOutOfBounds,
-            3 => ExceptionCode::CallIndirectOOB,
-            4 => ExceptionCode::IllegalArithmetic,
-            5 => ExceptionCode::MisalignedAtomicAccess,
-            _ => return ret,
-        }));
+        *error_out = {
+            let exception_code = match trap_out {
+                0 => ExceptionCode::Unreachable,
+                1 => ExceptionCode::IncorrectCallIndirectSignature,
+                2 => ExceptionCode::MemoryOutOfBounds,
+                3 => ExceptionCode::CallIndirectOOB,
+                4 => ExceptionCode::IllegalArithmetic,
+                5 => ExceptionCode::MisalignedAtomicAccess,
+                _ => return ret,
+            };
+            Some(RuntimeError::InvokeError(InvokeError::TrapCode {
+                code: exception_code,
+                // TODO:
+                srcloc: 0,
+            }))
+        };
     }
     ret
 }
@@ -467,8 +482,8 @@ impl RunnableModule for LLVMBackend {
         self.msm.clone()
     }
 
-    unsafe fn do_early_trap(&self, data: Box<dyn Any + Send>) -> ! {
-        throw_any(Box::leak(data))
+    unsafe fn do_early_trap(&self, data: RuntimeError) -> ! {
+        throw_runtime_error(Box::into_raw(Box::new(Some(data))))
     }
 }
 
diff --git a/lib/llvm-backend/src/code.rs b/lib/llvm-backend/src/code.rs
index 554628e254b..385cef47d18 100644
--- a/lib/llvm-backend/src/code.rs
+++ b/lib/llvm-backend/src/code.rs
@@ -35,6 +35,7 @@ use wasmer_runtime_core::{
     backend::{CacheGen, CompilerConfig, Token},
     cache::{Artifact, Error as CacheError},
     codegen::*,
+    error::RuntimeError,
     memory::MemoryType,
     module::{ModuleInfo, ModuleInner},
     parse::{wp_type_to_type, LoadError},
@@ -940,12 +941,11 @@ pub struct CodegenError {
 // prevents unused function elimination.
 #[no_mangle]
 pub unsafe extern "C" fn callback_trampoline(
-    b: *mut Option<Box<dyn std::any::Any>>,
+    b: *mut Option<RuntimeError>,
     callback: *mut BreakpointHandler,
 ) {
     let callback = Box::from_raw(callback);
-    let result: Result<(), Box<dyn std::any::Any + Send>> =
-        callback(BreakpointInfo { fault: None });
+    let result: Result<(), RuntimeError> = callback(BreakpointInfo { fault: None });
     match result {
         Ok(()) => *b = None,
         Err(e) => *b = Some(e),
diff --git a/lib/middleware-common/src/metering.rs b/lib/middleware-common/src/metering.rs
index 409035d4ba7..d4db44f905e 100644
--- a/lib/middleware-common/src/metering.rs
+++ b/lib/middleware-common/src/metering.rs
@@ -1,5 +1,6 @@
 use wasmer_runtime_core::{
     codegen::{Event, EventSink, FunctionMiddleware, InternalEvent},
+    error::RuntimeError,
     module::ModuleInfo,
     vm::{Ctx, InternalField},
     wasmparser::{Operator, Type as WpType, TypeOrFuncType as WpTypeOrFuncType},
@@ -96,7 +97,9 @@ impl FunctionMiddleware for Metering {
                             ty: WpTypeOrFuncType::Type(WpType::EmptyBlockType),
                         }));
                         sink.push(Event::Internal(InternalEvent::Breakpoint(Box::new(|_| {
-                            Err(Box::new(ExecutionLimitExceededError))
+                            Err(RuntimeError::Metering(Box::new(
+                                ExecutionLimitExceededError,
+                            )))
                         }))));
                         sink.push(Event::WasmOwned(Operator::End));
                     }
diff --git a/lib/runtime-c-api/src/import/mod.rs b/lib/runtime-c-api/src/import/mod.rs
index 79631de1ced..c6d724f51e0 100644
--- a/lib/runtime-c-api/src/import/mod.rs
+++ b/lib/runtime-c-api/src/import/mod.rs
@@ -21,6 +21,7 @@ use wasmer::import::{ImportObject, ImportObjectIterator};
 use wasmer::vm::Ctx;
 use wasmer::wasm::{Export, FuncSig, Global, Memory, Module, Table, Type};
 use wasmer_runtime_core::{
+    error::RuntimeError,
     export::{Context, FuncPointer},
     module::ImportName,
 };
@@ -723,7 +724,7 @@ pub unsafe extern "C" fn wasmer_trap(
 
     (&*ctx.module)
         .runnable_module
-        .do_early_trap(Box::new(error_message)); // never returns
+        .do_early_trap(RuntimeError::User(Box::new(error_message))); // never returns
 
     // cbindgen does not generate a binding for a function that
     // returns `!`. Since we also need to error in some cases, the
diff --git a/lib/runtime-c-api/tests/test-import-trap.c b/lib/runtime-c-api/tests/test-import-trap.c
index 0e28208eccc..c81df2311dc 100644
--- a/lib/runtime-c-api/tests/test-import-trap.c
+++ b/lib/runtime-c-api/tests/test-import-trap.c
@@ -69,7 +69,7 @@ int main()
     wasmer_last_error_message(error_str, error_len);
     printf("Error str: `%s`\n", error_str);
 
-    assert(0 == strcmp(error_str, "Call error: \"Hello\""));
+    assert(0 == strcmp(error_str, "Call error: User supplied error: \"Hello\""));
 
     printf("Destroying func\n");
     wasmer_import_func_destroy(func);
diff --git a/lib/runtime-c-api/wasmer.h b/lib/runtime-c-api/wasmer.h
index 1e7d9296d74..6262d8e8d0f 100644
--- a/lib/runtime-c-api/wasmer.h
+++ b/lib/runtime-c-api/wasmer.h
@@ -924,7 +924,7 @@ void *wasmer_instance_context_data_get(const wasmer_instance_context_t *ctx);
  * // Allocate them and set them on the given instance.
  * my_data *data = malloc(sizeof(my_data));
  * data->… = …;
- * wasmer_instance_context_data_set(instance, (void*) my_data);
+ * wasmer_instance_context_data_set(instance, (void*) data);
  *
  * // You can read your data.
  * {
diff --git a/lib/runtime-c-api/wasmer.hh b/lib/runtime-c-api/wasmer.hh
index 0bbf819ccca..647e637d03f 100644
--- a/lib/runtime-c-api/wasmer.hh
+++ b/lib/runtime-c-api/wasmer.hh
@@ -736,7 +736,7 @@ void *wasmer_instance_context_data_get(const wasmer_instance_context_t *ctx);
 /// // Allocate them and set them on the given instance.
 /// my_data *data = malloc(sizeof(my_data));
 /// data->… = …;
-/// wasmer_instance_context_data_set(instance, (void*) my_data);
+/// wasmer_instance_context_data_set(instance, (void*) data);
 ///
 /// // You can read your data.
 /// {
diff --git a/lib/runtime-core/src/backend.rs b/lib/runtime-core/src/backend.rs
index c6235475d8d..cbef1db3bc0 100644
--- a/lib/runtime-core/src/backend.rs
+++ b/lib/runtime-core/src/backend.rs
@@ -1,5 +1,5 @@
 use crate::{
-    error::CompileResult,
+    error::{CompileResult, RuntimeError},
     module::ModuleInner,
     state::ModuleStateMap,
     typed_func::Wasm,
@@ -282,7 +282,7 @@ pub trait RunnableModule: Send + Sync {
     fn get_trampoline(&self, info: &ModuleInfo, sig_index: SigIndex) -> Option<Wasm>;
 
     /// Trap an error.
-    unsafe fn do_early_trap(&self, data: Box<dyn Any + Send>) -> !;
+    unsafe fn do_early_trap(&self, data: RuntimeError) -> !;
 
     /// Returns the machine code associated with this module.
     fn get_code(&self) -> Option<&[u8]> {
diff --git a/lib/runtime-core/src/codegen.rs b/lib/runtime-core/src/codegen.rs
index 4e2bf74a4a2..6ff5c596c03 100644
--- a/lib/runtime-core/src/codegen.rs
+++ b/lib/runtime-core/src/codegen.rs
@@ -6,13 +6,12 @@ use crate::{
     backend::RunnableModule,
     backend::{CacheGen, Compiler, CompilerConfig, Features, Token},
     cache::{Artifact, Error as CacheError},
-    error::{CompileError, CompileResult},
+    error::{CompileError, CompileResult, RuntimeError},
     module::{ModuleInfo, ModuleInner},
     structures::Map,
     types::{FuncIndex, FuncSig, SigIndex},
 };
 use smallvec::SmallVec;
-use std::any::Any;
 use std::collections::HashMap;
 use std::fmt;
 use std::fmt::Debug;
@@ -23,7 +22,7 @@ use wasmparser::{Operator, Type as WpType};
 
 /// A type that defines a function pointer, which is called when breakpoints occur.
 pub type BreakpointHandler =
-    Box<dyn Fn(BreakpointInfo) -> Result<(), Box<dyn Any + Send>> + Send + Sync + 'static>;
+    Box<dyn Fn(BreakpointInfo) -> Result<(), RuntimeError> + Send + Sync + 'static>;
 
 /// Maps instruction pointers to their breakpoint handlers.
 pub type BreakpointMap = Arc<HashMap<usize, BreakpointHandler>>;
diff --git a/lib/runtime-core/src/error.rs b/lib/runtime-core/src/error.rs
index a685a8238f2..4b05fd35161 100644
--- a/lib/runtime-core/src/error.rs
+++ b/lib/runtime-core/src/error.rs
@@ -173,13 +173,99 @@ impl std::fmt::Display for LinkError {
 
 impl std::error::Error for LinkError {}
 
-/// This is the error type returned when calling
-/// a WebAssembly function.
-///
-/// The main way to do this is `Instance.call`.
+/// An error that happened while invoking a Wasm function.
+#[derive(Debug)]
+pub enum InvokeError {
+    /// Indicates an exceptional circumstance such as a bug in Wasmer (please file an issue!)
+    /// or a hardware failure.
+    FailedWithNoError,
+    /// Indicates that a trap occurred that is not known to Wasmer.
+    UnknownTrap {
+        /// The address that the trap occured at.
+        address: usize,
+        /// The name of the signal.
+        signal: &'static str,
+    },
+    /// A trap that Wasmer knows about occurred.
+    TrapCode {
+        /// The type of exception.
+        code: ExceptionCode,
+        /// Where in the Wasm file this trap orginated from.
+        srcloc: u32,
+    },
+    /// A trap occurred that Wasmer knows about but it had a trap code that
+    /// we weren't expecting or that we do not handle.  This error may be backend-specific.
+    UnknownTrapCode {
+        /// The trap code we saw but did not recognize.
+        trap_code: String,
+        /// Where in the Wasm file this trap orginated from.
+        srcloc: u32,
+    },
+    /// An "early trap" occurred.  TODO: document this properly
+    EarlyTrap(Box<RuntimeError>),
+    /// Indicates that a breakpoint was hit. The inner value is dependent upon
+    /// the middleware or backend being used.
+    Breakpoint(Box<RuntimeError>),
+}
+
+impl From<InvokeError> for RuntimeError {
+    fn from(other: InvokeError) -> RuntimeError {
+        match other {
+            InvokeError::EarlyTrap(re) | InvokeError::Breakpoint(re) => *re,
+            _ => RuntimeError::InvokeError(other),
+        }
+    }
+}
+
+impl std::error::Error for InvokeError {}
+
+impl std::fmt::Display for InvokeError {
+    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        match self {
+            InvokeError::FailedWithNoError => write!(f, "Invoke failed with no error"),
+            InvokeError::UnknownTrap { address, signal } => write!(
+                f,
+                "An unknown trap (`{}`) occured at 0x{:X}",
+                signal, address
+            ),
+            InvokeError::TrapCode { code, srcloc } => {
+                write!(f, "A `{}` trap was thrown at code offset {}", code, srcloc)
+            }
+            InvokeError::UnknownTrapCode { trap_code, srcloc } => write!(
+                f,
+                "A trap with an unknown trap code (`{}`) was thrown at code offset {}",
+                trap_code, srcloc
+            ),
+            InvokeError::EarlyTrap(rte) => write!(f, "Early trap: {}", rte),
+            InvokeError::Breakpoint(rte) => write!(f, "Breakpoint hit: {}", rte),
+        }
+    }
+}
+
+/// An `InternalError` is an error that happened inside of Wasmer and is a
+/// catch-all for errors that would otherwise be returned as
+/// `RuntimeError(Box::new(<string>))`.
 ///
-/// Comparing two `RuntimeError`s always evaluates to false.
-pub struct RuntimeError(pub Box<dyn Any + Send>);
+/// This type provides greater visibility into the kinds of things that may fail
+/// and improves the ability of users to handle them, though these errors may be
+/// extremely rare and impossible to handle.
+#[derive(Debug)]
+pub enum RuntimeError {
+    /// When an invoke returns an error
+    InvokeError(InvokeError),
+    /// A metering triggered error value.
+    ///
+    /// An error of this type indicates that it was returned by the metering system.
+    Metering(Box<dyn Any + Send>),
+    /// A frozen state of Wasm used to pause and resume execution.  Not strictly an
+    /// "error", but this happens while executing and therefore is a `RuntimeError`
+    /// from the persective of the caller that expected the code to fully execute.
+    InstanceImage(Box<dyn Any + Send>),
+    /// A user triggered error value.
+    ///
+    /// An error returned from a host function.
+    User(Box<dyn Any + Send>),
+}
 
 impl PartialEq for RuntimeError {
     fn eq(&self, _other: &RuntimeError) -> bool {
@@ -187,29 +273,33 @@ impl PartialEq for RuntimeError {
     }
 }
 
+impl std::error::Error for RuntimeError {}
+
 impl std::fmt::Display for RuntimeError {
     fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
-        let data = &*self.0;
-        if let Some(s) = data.downcast_ref::<String>() {
-            write!(f, "\"{}\"", s)
-        } else if let Some(s) = data.downcast_ref::<&str>() {
-            write!(f, "\"{}\"", s)
-        } else if let Some(exc_code) = data.downcast_ref::<ExceptionCode>() {
-            write!(f, "Caught exception of type \"{:?}\".", exc_code)
-        } else {
-            write!(f, "unknown error")
+        match self {
+            RuntimeError::InvokeError(ie) => write!(f, "Error when calling invoke: {}", ie),
+            RuntimeError::Metering(_) => write!(f, "unknown metering error type"),
+            RuntimeError::InstanceImage(_) => write!(
+                f,
+                "Execution interrupted by a suspend signal: instance image returned"
+            ),
+            RuntimeError::User(user_error) => {
+                write!(f, "User supplied error: ")?;
+                if let Some(s) = user_error.downcast_ref::<String>() {
+                    write!(f, "\"{}\"", s)
+                } else if let Some(s) = user_error.downcast_ref::<&str>() {
+                    write!(f, "\"{}\"", s)
+                } else if let Some(n) = user_error.downcast_ref::<i32>() {
+                    write!(f, "{}", n)
+                } else {
+                    write!(f, "unknown user error type")
+                }
+            }
         }
     }
 }
 
-impl std::fmt::Debug for RuntimeError {
-    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
-        write!(f, "{}", self)
-    }
-}
-
-impl std::error::Error for RuntimeError {}
-
 /// This error type is produced by resolving a wasm function
 /// given its name.
 ///
diff --git a/lib/runtime-core/src/fault.rs b/lib/runtime-core/src/fault.rs
index d8c985e09b9..4d7d919acf8 100644
--- a/lib/runtime-core/src/fault.rs
+++ b/lib/runtime-core/src/fault.rs
@@ -28,6 +28,7 @@ pub mod raw {
 }
 
 use crate::codegen::{BreakpointInfo, BreakpointMap};
+use crate::error::{InvokeError, RuntimeError};
 use crate::state::x64::{build_instance_image, read_stack, X64Register, GPR};
 use crate::state::{CodeVersion, ExecutionStateImage};
 use crate::vm;
@@ -36,7 +37,6 @@ use nix::sys::signal::{
     sigaction, SaFlags, SigAction, SigHandler, SigSet, Signal, SIGBUS, SIGFPE, SIGILL, SIGINT,
     SIGSEGV, SIGTRAP,
 };
-use std::any::Any;
 use std::cell::{Cell, RefCell, UnsafeCell};
 use std::ffi::c_void;
 use std::process;
@@ -61,7 +61,7 @@ type SetJmpBuffer = [i32; SETJMP_BUFFER_LEN];
 struct UnwindInfo {
     jmpbuf: SetJmpBuffer, // in
     breakpoints: Option<BreakpointMap>,
-    payload: Option<Box<dyn Any + Send>>, // out
+    payload: Option<Box<RuntimeError>>, // out
 }
 
 /// A store for boundary register preservation.
@@ -182,7 +182,7 @@ pub unsafe fn clear_wasm_interrupt() {
 pub unsafe fn catch_unsafe_unwind<R, F: FnOnce() -> R>(
     f: F,
     breakpoints: Option<BreakpointMap>,
-) -> Result<R, Box<dyn Any + Send>> {
+) -> Result<R, RuntimeError> {
     let unwind = UNWIND.with(|x| x.get());
     let old = (*unwind).take();
     *unwind = Some(UnwindInfo {
@@ -195,7 +195,7 @@ pub unsafe fn catch_unsafe_unwind<R, F: FnOnce() -> R>(
         // error
         let ret = (*unwind).as_mut().unwrap().payload.take().unwrap();
         *unwind = old;
-        Err(ret)
+        Err(*ret)
     } else {
         let ret = f();
         // implicit control flow to the error case...
@@ -205,7 +205,7 @@ pub unsafe fn catch_unsafe_unwind<R, F: FnOnce() -> R>(
 }
 
 /// Begins an unsafe unwind.
-pub unsafe fn begin_unsafe_unwind(e: Box<dyn Any + Send>) -> ! {
+pub unsafe fn begin_unsafe_unwind(e: Box<RuntimeError>) -> ! {
     let unwind = UNWIND.with(|x| x.get());
     let inner = (*unwind)
         .as_mut()
@@ -279,7 +279,11 @@ extern "C" fn signal_trap_handler(
     static ARCH: Architecture = Architecture::Aarch64;
 
     let mut should_unwind = false;
-    let mut unwind_result: Box<dyn Any + Send> = Box::new(());
+    let mut unwind_result: Option<Box<RuntimeError>> = None;
+    let get_unwind_result = |uw_result: Option<Box<RuntimeError>>| -> Box<RuntimeError> {
+        uw_result
+            .unwrap_or_else(|| Box::new(RuntimeError::InvokeError(InvokeError::FailedWithNoError)))
+    };
 
     unsafe {
         let fault = get_fault_info(siginfo as _, ucontext);
@@ -302,7 +306,7 @@ extern "C" fn signal_trap_handler(
                         ) {
                             match ib.ty {
                                 InlineBreakpointType::Middleware => {
-                                    let out: Option<Result<(), Box<dyn Any + Send>>> =
+                                    let out: Option<Result<(), RuntimeError>> =
                                         with_breakpoint_map(|bkpt_map| {
                                             bkpt_map.and_then(|x| x.get(&ip)).map(|x| {
                                                 x(BreakpointInfo {
@@ -313,7 +317,7 @@ extern "C" fn signal_trap_handler(
                                     if let Some(Ok(())) = out {
                                     } else if let Some(Err(e)) = out {
                                         should_unwind = true;
-                                        unwind_result = e;
+                                        unwind_result = Some(Box::new(e));
                                     }
                                 }
                             }
@@ -328,7 +332,7 @@ extern "C" fn signal_trap_handler(
             })
         });
         if should_unwind {
-            begin_unsafe_unwind(unwind_result);
+            begin_unsafe_unwind(get_unwind_result(unwind_result));
         }
         if early_return {
             return;
@@ -342,20 +346,22 @@ extern "C" fn signal_trap_handler(
             match Signal::from_c_int(signum) {
                 Ok(SIGTRAP) => {
                     // breakpoint
-                    let out: Option<Result<(), Box<dyn Any + Send>>> =
-                        with_breakpoint_map(|bkpt_map| {
-                            bkpt_map.and_then(|x| x.get(&(fault.ip.get()))).map(|x| {
-                                x(BreakpointInfo {
-                                    fault: Some(&fault),
-                                })
-                            })
+                    let out: Option<Result<(), RuntimeError>> =
+                        with_breakpoint_map(|bkpt_map| -> Option<Result<(), RuntimeError>> {
+                            bkpt_map.and_then(|x| x.get(&(fault.ip.get()))).map(
+                                |x| -> Result<(), RuntimeError> {
+                                    x(BreakpointInfo {
+                                        fault: Some(&fault),
+                                    })
+                                },
+                            )
                         });
                     match out {
                         Some(Ok(())) => {
                             return false;
                         }
                         Some(Err(e)) => {
-                            unwind_result = e;
+                            unwind_result = Some(Box::new(e));
                             return true;
                         }
                         None => {}
@@ -387,7 +393,7 @@ extern "C" fn signal_trap_handler(
             if is_suspend_signal {
                 // If this is a suspend signal, we parse the runtime state and return the resulting image.
                 let image = build_instance_image(ctx, es_image);
-                unwind_result = Box::new(image);
+                unwind_result = Some(Box::new(RuntimeError::InstanceImage(Box::new(image))));
             } else {
                 // Otherwise, this is a real exception and we just throw it to the caller.
                 if !es_image.frames.is_empty() {
@@ -415,7 +421,12 @@ extern "C" fn signal_trap_handler(
                     None
                 });
                 if let Some(code) = exc_code {
-                    unwind_result = Box::new(code);
+                    unwind_result =
+                        Some(Box::new(RuntimeError::InvokeError(InvokeError::TrapCode {
+                            code,
+                            // TODO:
+                            srcloc: 0,
+                        })));
                 }
             }
 
@@ -423,7 +434,7 @@ extern "C" fn signal_trap_handler(
         });
 
         if should_unwind {
-            begin_unsafe_unwind(unwind_result);
+            begin_unsafe_unwind(get_unwind_result(unwind_result));
         }
     }
 }
diff --git a/lib/runtime-core/src/instance.rs b/lib/runtime-core/src/instance.rs
index 48e59d4ec65..7fa7a687261 100644
--- a/lib/runtime-core/src/instance.rs
+++ b/lib/runtime-core/src/instance.rs
@@ -5,7 +5,7 @@
 use crate::{
     backend::RunnableModule,
     backing::{ImportBacking, LocalBacking},
-    error::{CallResult, ResolveError, ResolveResult, Result, RuntimeError},
+    error::{CallResult, InvokeError, ResolveError, ResolveResult, Result, RuntimeError},
     export::{Context, Export, ExportIter, Exportable, FuncPointer},
     global::Global,
     import::{ImportObject, LikeNamespace},
@@ -584,25 +584,30 @@ pub(crate) fn call_func_with_index_inner(
         invoke_env,
     } = wasm;
 
-    let run_wasm = |result_space: *mut u64| unsafe {
+    let run_wasm = |result_space: *mut u64| -> CallResult<()> {
         let mut error_out = None;
 
-        let success = invoke(
-            trampoline,
-            ctx_ptr,
-            func_ptr,
-            raw_args.as_ptr(),
-            result_space,
-            &mut error_out,
-            invoke_env,
-        );
+        let success = unsafe {
+            invoke(
+                trampoline,
+                ctx_ptr,
+                func_ptr,
+                raw_args.as_ptr(),
+                result_space,
+                &mut error_out,
+                invoke_env,
+            )
+        };
 
         if success {
             Ok(())
         } else {
-            Err(error_out
-                .map(RuntimeError)
-                .unwrap_or_else(|| RuntimeError(Box::new("invoke(): Unknown error".to_string()))))
+            let error: RuntimeError = error_out.map_or_else(
+                || RuntimeError::InvokeError(InvokeError::FailedWithNoError),
+                Into::into,
+            );
+            dbg!(&error);
+            Err(error.into())
         }
     };
 
diff --git a/lib/runtime-core/src/state.rs b/lib/runtime-core/src/state.rs
index 55809e965d7..d7d5a6ee1a8 100644
--- a/lib/runtime-core/src/state.rs
+++ b/lib/runtime-core/src/state.rs
@@ -699,13 +699,13 @@ pub mod x64 {
     pub use super::x64_decl::*;
     use super::*;
     use crate::codegen::BreakpointMap;
+    use crate::error::RuntimeError;
     use crate::fault::{
         catch_unsafe_unwind, get_boundary_register_preservation, run_on_alternative_stack,
     };
     use crate::structures::TypedIndex;
     use crate::types::LocalGlobalIndex;
     use crate::vm::Ctx;
-    use std::any::Any;
 
     #[allow(clippy::cast_ptr_alignment)]
     unsafe fn compute_vmctx_deref(vmctx: *const Ctx, seq: &[usize]) -> u64 {
@@ -738,7 +738,7 @@ pub mod x64 {
         image: InstanceImage,
         vmctx: &mut Ctx,
         breakpoints: Option<BreakpointMap>,
-    ) -> Result<u64, Box<dyn Any + Send>> {
+    ) -> Result<u64, RuntimeError> {
         let mut stack: Vec<u64> = vec![0; 1048576 * 8 / 8]; // 8MB stack
         let mut stack_offset: usize = stack.len();
 
diff --git a/lib/runtime-core/src/tiering.rs b/lib/runtime-core/src/tiering.rs
index 83ebfd47159..2aa324232f4 100644
--- a/lib/runtime-core/src/tiering.rs
+++ b/lib/runtime-core/src/tiering.rs
@@ -2,6 +2,7 @@
 //! as runtime.
 use crate::backend::{Compiler, CompilerConfig};
 use crate::compile_with_config;
+use crate::error::RuntimeError;
 use crate::fault::{
     catch_unsafe_unwind, ensure_sighandler, pop_code_version, push_code_version, with_ctx,
 };
@@ -223,23 +224,26 @@ pub unsafe fn run_tiering<F: Fn(InteractiveShellContext) -> ShellExitOperation>(
             }
         });
         if let Err(e) = ret {
-            if let Ok(new_image) = e.downcast::<InstanceImage>() {
+            match e {
                 // Tier switch event
-                if !was_sigint_triggered_fault() && opt_state.outcome.lock().unwrap().is_some() {
-                    resume_image = Some(*new_image);
-                    continue;
-                }
-                let op = interactive_shell(InteractiveShellContext {
-                    image: Some(*new_image),
-                    patched: n_versions.get() > 1,
-                });
-                match op {
-                    ShellExitOperation::ContinueWith(new_image) => {
-                        resume_image = Some(new_image);
+                RuntimeError::InstanceImage(ii_value) => {
+                    let new_image = ii_value.downcast::<InstanceImage>().unwrap();
+                    if !was_sigint_triggered_fault() && opt_state.outcome.lock().unwrap().is_some()
+                    {
+                        resume_image = Some(*new_image);
+                        continue;
+                    }
+                    let op = interactive_shell(InteractiveShellContext {
+                        image: Some(*new_image),
+                        patched: n_versions.get() > 1,
+                    });
+                    match op {
+                        ShellExitOperation::ContinueWith(new_image) => {
+                            resume_image = Some(new_image);
+                        }
                     }
                 }
-            } else {
-                return Err("Error while executing WebAssembly".into());
+                _ => return Err("Error while executing WebAssembly".into()),
             }
         } else {
             return Ok(());
diff --git a/lib/runtime-core/src/typed_func.rs b/lib/runtime-core/src/typed_func.rs
index a6337bc5888..5cef19ca4dc 100644
--- a/lib/runtime-core/src/typed_func.rs
+++ b/lib/runtime-core/src/typed_func.rs
@@ -1,7 +1,7 @@
 //! The typed func module implements a way of representing a wasm function
 //! with the correct types from rust. Function calls using a typed func have a low overhead.
 use crate::{
-    error::RuntimeError,
+    error::{InvokeError, RuntimeError},
     export::{Context, Export, FuncPointer},
     import::IsExport,
     types::{FuncSig, NativeWasmType, Type, WasmExternType},
@@ -37,7 +37,7 @@ pub type Invoke = unsafe extern "C" fn(
     func: NonNull<vm::Func>,
     args: *const u64,
     rets: *mut u64,
-    error_out: *mut Option<Box<dyn Any + Send>>,
+    error_out: *mut Option<RuntimeError>,
     extra: Option<NonNull<c_void>>,
 ) -> bool;
 
@@ -340,7 +340,9 @@ impl<'a> DynamicFunc<'a> {
                 Err(e) => {
                     // At this point, there is an error that needs to be trapped.
                     drop(args); // Release the Vec which will leak otherwise.
-                    (&*vmctx.module).runnable_module.do_early_trap(e)
+                    (&*vmctx.module)
+                        .runnable_module
+                        .do_early_trap(RuntimeError::User(e))
                 }
             }
         }
@@ -588,9 +590,7 @@ macro_rules! impl_traits {
                 ) {
                     Ok(Rets::from_ret_array(rets))
                 } else {
-                    Err(error_out.map(RuntimeError).unwrap_or_else(|| {
-                        RuntimeError(Box::new("invoke(): Unknown error".to_string()))
-                    }))
+                    Err(error_out.map_or_else(|| RuntimeError::InvokeError(InvokeError::FailedWithNoError), Into::into))
                 }
             }
         }
@@ -678,9 +678,10 @@ macro_rules! impl_traits {
                         Ok(Ok(returns)) => return returns.into_c_struct(),
                         Ok(Err(err)) => {
                             let b: Box<_> = err.into();
-                            b as Box<dyn Any + Send>
+                            RuntimeError::User(b as Box<dyn Any + Send>)
                         },
-                        Err(err) => err,
+                        // TODO(blocking): this line is wrong!
+                        Err(err) => RuntimeError::User(err),
                     };
 
                     // At this point, there is an error that needs to
@@ -791,9 +792,10 @@ macro_rules! impl_traits {
                         Ok(Ok(returns)) => return returns.into_c_struct(),
                         Ok(Err(err)) => {
                             let b: Box<_> = err.into();
-                            b as Box<dyn Any + Send>
+                            RuntimeError::User(b as Box<dyn Any + Send>)
                         },
-                        Err(err) => err,
+                        // TODO(blocking): this line is wrong!
+                        Err(err) => RuntimeError::User(err),
                     };
 
                     // At this point, there is an error that needs to
diff --git a/lib/runtime-core/src/vm.rs b/lib/runtime-core/src/vm.rs
index a9a1a2ad9b0..874d18dc9b9 100644
--- a/lib/runtime-core/src/vm.rs
+++ b/lib/runtime-core/src/vm.rs
@@ -1079,10 +1079,10 @@ mod vm_ctx_tests {
         use super::Func;
         use crate::backend::{sys::Memory, CacheGen, RunnableModule};
         use crate::cache::Error as CacheError;
+        use crate::error::RuntimeError;
         use crate::typed_func::Wasm;
         use crate::types::{LocalFuncIndex, SigIndex};
         use indexmap::IndexMap;
-        use std::any::Any;
         use std::collections::HashMap;
         use std::ptr::NonNull;
         struct Placeholder;
@@ -1098,7 +1098,7 @@ mod vm_ctx_tests {
             fn get_trampoline(&self, _module: &ModuleInfo, _sig_index: SigIndex) -> Option<Wasm> {
                 unimplemented!("generate_module::get_trampoline")
             }
-            unsafe fn do_early_trap(&self, _: Box<dyn Any + Send>) -> ! {
+            unsafe fn do_early_trap(&self, _: RuntimeError) -> ! {
                 unimplemented!("generate_module::do_early_trap")
             }
         }
diff --git a/lib/runtime/examples/call.rs b/lib/runtime/examples/call.rs
index 46ccc5aa693..2d6ee562de2 100644
--- a/lib/runtime/examples/call.rs
+++ b/lib/runtime/examples/call.rs
@@ -71,8 +71,11 @@ fn main() -> Result<(), error::Error> {
     println!("result: {:?}", result);
 
     if let Err(e) = result {
-        if let Ok(exit_code) = e.0.downcast::<ExitCode>() {
+        if let RuntimeError::User(ue) = e {
+            let exit_code = ue.downcast_ref::<ExitCode>().unwrap();
             println!("exit code: {:?}", exit_code);
+        } else {
+            panic!("Found error that wasn't a user error!: {}", e)
         }
     }
 
diff --git a/lib/singlepass-backend/src/codegen_x64.rs b/lib/singlepass-backend/src/codegen_x64.rs
index e51db5b7c5b..bc666d1ff96 100644
--- a/lib/singlepass-backend/src/codegen_x64.rs
+++ b/lib/singlepass-backend/src/codegen_x64.rs
@@ -10,7 +10,6 @@ use dynasmrt::x64::Assembler;
 use dynasmrt::{AssemblyOffset, DynamicLabel, DynasmApi, DynasmLabelApi};
 use smallvec::SmallVec;
 use std::{
-    any::Any,
     collections::{BTreeMap, HashMap},
     ffi::c_void,
     iter, mem,
@@ -27,6 +26,7 @@ use wasmer_runtime_core::{
     },
     cache::{Artifact, Error as CacheError},
     codegen::*,
+    error::{InvokeError, RuntimeError},
     fault::{self, raw::register_preservation_trampoline},
     loader::CodeMemory,
     memory::MemoryType,
@@ -214,7 +214,7 @@ pub struct X64FunctionCode {
     breakpoints: Option<
         HashMap<
             AssemblyOffset,
-            Box<dyn Fn(BreakpointInfo) -> Result<(), Box<dyn Any + Send>> + Send + Sync + 'static>,
+            Box<dyn Fn(BreakpointInfo) -> Result<(), RuntimeError> + Send + Sync + 'static>,
         >,
     >,
     returns: SmallVec<[WpType; 1]>,
@@ -507,7 +507,7 @@ impl RunnableModule for X64ExecutionContext {
             func: NonNull<vm::Func>,
             args: *const u64,
             rets: *mut u64,
-            error_out: *mut Option<Box<dyn Any + Send>>,
+            error_out: *mut Option<RuntimeError>,
             num_params_plus_one: Option<NonNull<c_void>>,
         ) -> bool {
             let rm: &Box<dyn RunnableModule> = &(&*(*ctx).module).runnable_module;
@@ -655,7 +655,7 @@ impl RunnableModule for X64ExecutionContext {
                     true
                 }
                 Err(err) => {
-                    *error_out = Some(err);
+                    *error_out = Some(InvokeError::Breakpoint(Box::new(err)).into());
                     false
                 }
             };
@@ -680,8 +680,8 @@ impl RunnableModule for X64ExecutionContext {
         })
     }
 
-    unsafe fn do_early_trap(&self, data: Box<dyn Any + Send>) -> ! {
-        fault::begin_unsafe_unwind(data);
+    unsafe fn do_early_trap(&self, data: RuntimeError) -> ! {
+        fault::begin_unsafe_unwind(Box::new(data));
     }
 
     fn get_code(&self) -> Option<&[u8]> {
diff --git a/src/commands/run.rs b/src/commands/run.rs
index b58075fd777..12d3335e90d 100644
--- a/src/commands/run.rs
+++ b/src/commands/run.rs
@@ -21,6 +21,7 @@ use wasmer_runtime::{
 use wasmer_runtime_core::{
     self,
     backend::{Compiler, CompilerConfig, MemoryBoundCheckMode},
+    error::RuntimeError,
     loader::{Instance as LoadedInstance, LocalLoader},
     Module,
 };
@@ -437,9 +438,12 @@ fn execute_wasi(
         }
 
         if let Err(ref err) = result {
-            if let Some(error_code) = err.0.downcast_ref::<wasmer_wasi::ExitCode>() {
-                std::process::exit(error_code.code as i32)
+            if let RuntimeError::User(user_error) = err {
+                if let Some(error_code) = user_error.downcast_ref::<wasmer_wasi::ExitCode>() {
+                    std::process::exit(error_code.code as i32)
+                }
             }
+
             return Err(format!("error: {:?}", err));
         }
     }
diff --git a/tests/high_level_api.rs b/tests/high_level_api.rs
index 389e20c411b..5d9ae70fb03 100644
--- a/tests/high_level_api.rs
+++ b/tests/high_level_api.rs
@@ -268,7 +268,7 @@ wasmer_backends! {
 
         let result = foo.call();
 
-        if let Err(RuntimeError(e)) = result {
+        if let Err(RuntimeError::User(e)) = result {
             let exit_code = e.downcast::<ExitCode>().unwrap();
             assert_eq!(exit_code.code, 42);
         } else {
diff --git a/tests/imports.rs b/tests/imports.rs
index e4ce076719c..ed1a2da81d7 100644
--- a/tests/imports.rs
+++ b/tests/imports.rs
@@ -52,7 +52,7 @@ macro_rules! call_and_assert {
                 expected_value,
                 concat!("Expected right when calling `", stringify!($function), "`.")
             ),
-            (Err(RuntimeError(data)), Err(RuntimeError(expected_data))) => {
+            (Err(RuntimeError::User(data)), Err(RuntimeError::User(expected_data))) => {
                 if let (Some(data), Some(expected_data)) = (
                     data.downcast_ref::<&str>(),
                     expected_data.downcast_ref::<&str>(),
@@ -406,7 +406,7 @@ wasmer_backends! {
     test!( test_fn, function_fn(i32) -> i32, (1) == Ok(2));
     test!( test_closure, function_closure(i32) -> i32, (1) == Ok(2));
     test!( test_fn_dynamic, function_fn_dynamic(i32) -> i32, (1) == Ok(2));
-    test!( test_fn_dynamic_panic, function_fn_dynamic_panic(i32) -> i32, (1) == Err(RuntimeError(Box::new("test"))));
+    test!( test_fn_dynamic_panic, function_fn_dynamic_panic(i32) -> i32, (1) == Err(RuntimeError::User(Box::new("test"))));
     test!(
 
         test_closure_dynamic_0,
@@ -460,31 +460,31 @@ wasmer_backends! {
 
         test_fn_trap,
         function_fn_trap(i32) -> i32,
-        (1) == Err(RuntimeError(Box::new(format!("foo {}", 2))))
+        (1) == Err(RuntimeError::User(Box::new(format!("foo {}", 2))))
     );
     test!(
 
         test_closure_trap,
         function_closure_trap(i32) -> i32,
-        (1) == Err(RuntimeError(Box::new(format!("bar {}", 2))))
+        (1) == Err(RuntimeError::User(Box::new(format!("bar {}", 2))))
     );
     test!(
 
         test_fn_trap_with_vmctx,
         function_fn_trap_with_vmctx(i32) -> i32,
-        (1) == Err(RuntimeError(Box::new(format!("baz {}", 2 + SHIFT))))
+        (1) == Err(RuntimeError::User(Box::new(format!("baz {}", 2 + SHIFT))))
     );
     test!(
 
         test_closure_trap_with_vmctx,
         function_closure_trap_with_vmctx(i32) -> i32,
-        (1) == Err(RuntimeError(Box::new(format!("qux {}", 2 + SHIFT))))
+        (1) == Err(RuntimeError::User(Box::new(format!("qux {}", 2 + SHIFT))))
     );
     test!(
 
         test_closure_trap_with_vmctx_and_env,
         function_closure_trap_with_vmctx_and_env(i32) -> i32,
-        (1) == Err(RuntimeError(Box::new(format!("! {}", 2 + shift + SHIFT))))
+        (1) == Err(RuntimeError::User(Box::new(format!("! {}", 2 + shift + SHIFT))))
     );
 
     #[test]
diff --git a/tests/middleware_common.rs b/tests/middleware_common.rs
index 90516af0c30..ca423661df9 100644
--- a/tests/middleware_common.rs
+++ b/tests/middleware_common.rs
@@ -6,6 +6,7 @@ use wasmer::wasm::Func;
 use wasmer_middleware_common::metering::*;
 use wasmer_runtime_core::codegen::ModuleCodeGenerator;
 use wasmer_runtime_core::codegen::{MiddlewareChain, StreamingCompiler};
+use wasmer_runtime_core::error::RuntimeError;
 use wasmer_runtime_core::fault::{pop_code_version, push_code_version};
 use wasmer_runtime_core::state::CodeVersion;
 
@@ -179,10 +180,13 @@ fn middleware_test_traps_after_costly_call(backend: &'static str, compiler: impl
     }
 
     let err = result.unwrap_err();
-    assert!(err
-        .0
-        .downcast_ref::<ExecutionLimitExceededError>()
-        .is_some());
+    if let RuntimeError::Metering(metering_err) = err {
+        assert!(metering_err
+            .downcast_ref::<ExecutionLimitExceededError>()
+            .is_some());
+    } else {
+        assert!(false, "metering error not found");
+    }
 
     // verify it used the correct number of points
     assert_eq!(get_points_used(&instance), 109); // Used points will be slightly more than `limit` because of the way we do gas checking.