Add PRETTY_PRINT_DEBUG_SYMBOLS

compiler/module/src/symbol.rs

@@ -9,6 +9,14 @@ use std::{fmt, u32};
 #[derive(Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord)]
 pub struct Symbol(u64);
 
+// When this is `true` (which it normally should be), Symbol's Debug::fmt implementation
+// attempts to pretty print debug symbols using interns recorded using
+// register_debug_idents calls (which should be made in debug mode).
+// Set it to false if you want to see the raw ModuleId and IdentId ints,
+// but please set it back to true before checking in the result!
+#[cfg(debug_assertions)]
+const PRETTY_PRINT_DEBUG_SYMBOLS: bool = true;
+
 /// In Debug builds only, Symbol has a name() method that lets
 /// you look up its name in a global intern table. This table is
 /// behind a mutex, so it is neither populated nor available in release builds.
@@ -101,6 +109,7 @@ impl Symbol {
 impl fmt::Debug for Symbol {
     #[cfg(debug_assertions)]
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        if PRETTY_PRINT_DEBUG_SYMBOLS {
             let module_id = self.module_id();
             let ident_id = self.ident_id();
 
@@ -122,6 +131,9 @@ impl fmt::Debug for Symbol {
                     fallback_debug_fmt(*self, f)
                 }
             }
+        } else {
+            fallback_debug_fmt(*self, f)
+        }
     }
 
     #[cfg(not(debug_assertions))]