chore: provide a better error message for unknown cheatcodes (#7436)

crates/cheatcodes/src/inspector.rs

@@ -222,7 +222,17 @@ impl Cheatcodes {
         call: &CallInputs,
     ) -> Result {
         // decode the cheatcode call
-        let decoded = Vm::VmCalls::abi_decode(&call.input, false)?;
+        let decoded = Vm::VmCalls::abi_decode(&call.input, false).map_err(|e| {
+            if let alloy_sol_types::Error::UnknownSelector { name: _, selector } = e {
+                let msg = format!(
+                    "unknown cheatcode with selector {selector}; \
+                     you may have a mismatch between the `Vm` interface (likely in `forge-std`) \
+                     and the `forge` version"
+                );
+                return alloy_sol_types::Error::Other(std::borrow::Cow::Owned(msg));
+            }
+            e
+        })?;
         let caller = call.context.caller;
 
         // ensure the caller is allowed to execute cheatcodes,