Address some PR feedback

crates/wasmtime/src/config.rs

@@ -1453,10 +1453,7 @@ impl Config {
     }
 
     /// Configures whether or not a coredump should be generated and attached to
-    /// the anyhow::Error when a trap is raised. Because a coredump is a
-    /// superset of a backtrace, setting this to true will override the setting
-    /// for `wasm_backtrace`, resulting in a WasmCoreDump being attached to the
-    /// raised error rather than a WasmBacktrace.
+    /// the anyhow::Error when a trap is raised.
     ///
     /// This option is disabled by default.
     pub fn coredump_on_trap(&mut self, enable: bool) -> &mut Self {

crates/wasmtime/src/coredump.rs

@@ -4,16 +4,17 @@ use crate::{store::StoreOpaque, Global, Instance, Memory, Module, WasmBacktrace}
 
 /// Representation of a core dump of a WebAssembly module
 ///
-/// This structure is attached to the [`anyhow::Error`] returned from many
-/// Wasmtime functions that execute WebAssembly such as [`Instance::new`] or
-/// [`Func::call`]. This can be acquired with the [`anyhow::Error::downcast`]
-/// family of methods to programmatically inspect the coredump. Otherwise since
-/// it's part of the error returned this will get printed along with the rest of
-/// the error when the error is logged.
+/// When the Config::coredump_on_trap option is enabled this structure is
+/// attached to the [`anyhow::Error`] returned from many Wasmtime functions that
+/// execute WebAssembly such as [`Instance::new`] or [`Func::call`]. This can be
+/// acquired with the [`anyhow::Error::downcast`] family of methods to
+/// programmatically inspect the coredump. Otherwise since it's part of the
+/// error returned this will get printed along with the rest of the error when
+/// the error is logged.
 ///
-/// TODO: Notably absent from this structure at the moment are any locals or
-/// operand values for the stack frames. More work is needed to be able to
-/// recover those when a trap occurs, at which point they will be added here.
+/// Note that some state, such as Wasm locals or values on the operand stack,
+/// may be optimized away by the compiler or otherwise not recovered in the
+/// coredump.
 ///
 /// Capturing of wasm coredumps can be configured through the
 /// [`Config::coredump_on_trap`](crate::Config::coredump_on_trap) method.

crates/wasmtime/src/trap.rs

@@ -85,7 +85,7 @@ pub(crate) fn from_runtime_box(
         backtrace,
         coredumpstack,
     } = *runtime_trap;
-    let (error, pc) = match reason {
+    let (mut error, pc) = match reason {
         // For user-defined errors they're already an `anyhow::Error` so no
         // conversion is really necessary here, but a `backtrace` may have
         // been captured so it's attempted to get inserted here.
@@ -127,22 +127,19 @@ pub(crate) fn from_runtime_box(
         wasmtime_runtime::TrapReason::Wasm(trap_code) => (trap_code.into(), None),
     };
 
-    match (coredumpstack, backtrace) {
-        (None, None) => error,
-        (None, Some(bt)) => {
-            let bt = WasmBacktrace::from_captured(store, bt, pc);
-            if !bt.wasm_trace.is_empty() {
-                error.context(bt)
-            } else {
-                error
-            }
-        }
-        (Some(coredump), _) => {
-            let bt = WasmBacktrace::from_captured(store, coredump.bt, pc);
-            let cd = WasmCoreDump::new(store, bt);
-            error.context(cd)
+    if let Some(bt) = backtrace {
+        let bt = WasmBacktrace::from_captured(store, bt, pc);
+        if !bt.wasm_trace.is_empty() {
+            error = error.context(bt);
         }
     }
+
+    if let Some(coredump) = coredumpstack {
+        let bt = WasmBacktrace::from_captured(store, coredump.bt, pc);
+        let cd = WasmCoreDump::new(store, bt);
+        error = error.context(cd);
+    }
+    error
 }
 
 /// Representation of a backtrace of function frames in a WebAssembly module for