Upgrade cpp_demangle to the latest version. (#732)

cpp_demangle 0.5.0 drops the `Display` impl on the `Symbol` object because it can
subtly violate the `Display` contract. The recommended replacement is
`Symbol::demangle`.

Changelog: https://github.com/gimli-rs/cpp_demangle/blob/0.5.0/CHANGELOG.md#050

Author: khuey

Cargo.lock

@@ -34,7 +34,7 @@ rustc-demangle = "0.1.24"
 serde = { version = "1.0", optional = true, features = ['derive'] }
 
 # Optionally demangle C++ frames' symbols in backtraces.
-cpp_demangle = { default-features = false, version = "0.4.0", optional = true, features = [
+cpp_demangle = { default-features = false, version = "0.5.0", optional = true, features = [
   "alloc",
 ] }
 

Cargo.toml

@@ -373,8 +373,13 @@ impl<'a> fmt::Display for SymbolName<'a> {
 
         #[cfg(feature = "cpp_demangle")]
         {
+            // This may fail to print if the demangled symbol isn't actually
+            // valid, so handle the error here gracefully by not propagating
+            // it outwards.
             if let Some(ref cpp) = self.cpp_demangled.0 {
-                return cpp.fmt(f);
+                if let Ok(s) = cpp.demangle() {
+                    return s.fmt(f);
+                }
             }
         }
 
@@ -390,14 +395,11 @@ impl<'a> fmt::Debug for SymbolName<'a> {
 
         #[cfg(all(feature = "std", feature = "cpp_demangle"))]
         {
-            use std::fmt::Write;
-
-            // This may to print if the demangled symbol isn't actually
+            // This may fail to print if the demangled symbol isn't actually
             // valid, so handle the error here gracefully by not propagating
             // it outwards.
             if let Some(ref cpp) = self.cpp_demangled.0 {
-                let mut s = String::new();
-                if write!(s, "{cpp}").is_ok() {
+                if let Ok(s) = cpp.demangle() {
                     return s.fmt(f);
                 }
             }