bump rust-toolchain to 1.78

crates/nu-engine/src/eval.rs

@@ -198,7 +198,7 @@ pub fn redirect_env(engine_state: &EngineState, caller_stack: &mut Stack, callee
     }
 
     // set config to callee config, to capture any updates to that
-    caller_stack.config = callee_stack.config.clone();
+    caller_stack.config.clone_from(&callee_stack.config)
 }
 
 fn eval_external(

crates/nu-protocol/src/engine/argument.rs

@@ -71,7 +71,7 @@ impl Argument {
 }
 
 /// Stores the argument context for calls in IR evaluation.
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, Default)]
 pub struct ArgumentStack {
     arguments: Vec<Argument>,
 }

crates/nu-protocol/src/engine/error_handler.rs

@@ -10,7 +10,7 @@ pub struct ErrorHandler {
 }
 
 /// Keeps track of error handlers pushed during evaluation of an IR block.
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, Default)]
 pub struct ErrorHandlerStack {
     handlers: Vec<ErrorHandler>,
 }

rust-toolchain.toml

@@ -16,4 +16,4 @@ profile = "default"
 # use in nushell, we may opt to use the bleeding edge stable version of rust.
 # I believe rust is on a 6 week release cycle and nushell is on a 4 week release cycle.
 # So, every two nushell releases, this version number should be bumped by one.
-channel = "1.77.2"
+channel = "1.78.0"