Derive Debug for FaerieProduct (#1252)

This allows using Result::unwrap_err for `Result`s with FaerieProducts.

cranelift/faerie/src/backend.rs

@@ -322,6 +322,7 @@ impl Backend for FaerieBackend {
 /// This is the output of `Module`'s
 /// [`finish`](../cranelift_module/struct.Module.html#method.finish) function.
 /// It provides functions for writing out the object file to memory or a file.
+#[derive(Debug)]
 pub struct FaerieProduct {
     /// Faerie artifact with all functions, data, and links from the module defined
     pub artifact: faerie::Artifact,

cranelift/faerie/src/traps.rs

@@ -4,6 +4,7 @@
 use cranelift_codegen::{binemit, ir};
 
 /// Record of the arguments cranelift passes to `TrapSink::trap`
+#[derive(Debug)]
 pub struct FaerieTrapSite {
     /// Offset into function
     pub offset: binemit::CodeOffset,
@@ -14,6 +15,7 @@ pub struct FaerieTrapSite {
 }
 
 /// Record of the trap sites for a given function
+#[derive(Debug)]
 pub struct FaerieTrapSink {
     /// Name of function
     pub name: String,
@@ -45,6 +47,7 @@ impl binemit::TrapSink for FaerieTrapSink {
 }
 
 /// Collection of all `FaerieTrapSink`s for the module
+#[derive(Debug)]
 pub struct FaerieTrapManifest {
     /// All `FaerieTrapSink` for the module
     pub sinks: Vec<FaerieTrapSink>,