Generate parameter name rather than type

tool/src/demo_gen/terminus.rs

@@ -44,8 +44,8 @@ struct MethodDependency {
     /// Parameters to pass into the method.
     params: Vec<ParamInfo>,
 
-    /// The type name that this method belongs to. Currently used by [`OutParam`] for better default parameter names.
-    owning_type: String,
+    /// The Rust parameter that we're attempting to construct with this method. Currently used by [`OutParam`] for better default parameter names.
+    owning_param: Option<String>,
 }
 
 pub(super) struct RenderTerminusContext<'ctx, 'tcx> {
@@ -59,11 +59,11 @@ pub(super) struct RenderTerminusContext<'ctx, 'tcx> {
 }
 
 impl MethodDependency {
-    pub fn new(method_js: String, owning_type: String) -> Self {
+    pub fn new(method_js: String, owning_param: Option<String>) -> Self {
         MethodDependency {
             method_js,
             params: Vec::new(),
-            owning_type,
+            owning_param,
         }
     }
 }
@@ -161,7 +161,7 @@ impl<'ctx, 'tcx> RenderTerminusContext<'ctx, 'tcx> {
         // which I find easier easier to represent as a parameter to each function than something like an updating the current node in the struct.
         let mut root = MethodDependency::new(
             self.get_constructor_js(type_name.clone(), method),
-            type_name.clone(),
+            None,
         );
 
         // And then we just treat the terminus as a regular constructor method:
@@ -195,9 +195,12 @@ impl<'ctx, 'tcx> RenderTerminusContext<'ctx, 'tcx> {
         let attrs_default = attrs.unwrap_or_default();
         // This only works for enums, since otherwise we break the type into its component parts.
         let label = if attrs_default.input_cfg.label.is_empty() {
+            let owning_str = node.owning_param.as_ref().map(|p| {
+                format!("{}:", heck::AsUpperCamelCase(p))
+            }).unwrap_or_default();
             format!(
-                "{}:{}",
-                heck::AsUpperCamelCase(node.owning_type.clone()),
+                "{}{}",
+                owning_str,
                 heck::AsUpperCamelCase(param_name.clone())
             )
             .to_string()
@@ -298,7 +301,7 @@ impl<'ctx, 'tcx> RenderTerminusContext<'ctx, 'tcx> {
                     return;
                 }
 
-                self.evaluate_op_constructors(op, type_name.to_string(), node);
+                self.evaluate_op_constructors(op, type_name.to_string(), param_name, node);
             }
             Type::Struct(s) => {
                 let st = s.resolve(self.tcx);
@@ -309,7 +312,7 @@ impl<'ctx, 'tcx> RenderTerminusContext<'ctx, 'tcx> {
                         .push_error(format!("Found usage of disabled type {type_name}"))
                 }
 
-                self.evaluate_struct_fields(st, type_name.to_string(), node);
+                self.evaluate_struct_fields(st, type_name.to_string(), param_name, node);
             }
             Type::DiplomatOption(ref inner) => {
                 self.evaluate_param(inner, param_name, node, param_attrs)
@@ -353,6 +356,7 @@ impl<'ctx, 'tcx> RenderTerminusContext<'ctx, 'tcx> {
         &mut self,
         op: &OpaqueDef,
         type_name: String,
+        param_name : String,
         node: &mut MethodDependency,
     ) {
         let mut usable_constructor = false;
@@ -380,7 +384,7 @@ impl<'ctx, 'tcx> RenderTerminusContext<'ctx, 'tcx> {
 
                 let mut child = MethodDependency::new(
                     self.get_constructor_js(type_name.to_string(), method),
-                    type_name,
+                    Some(param_name),
                 );
 
                 let call = self.evaluate_constructor(method, &mut child);
@@ -415,6 +419,7 @@ impl<'ctx, 'tcx> RenderTerminusContext<'ctx, 'tcx> {
         &mut self,
         st: &StructDef,
         type_name: String,
+        param_name: String,
         node: &mut MethodDependency,
     ) {
         self.terminus_info
@@ -425,7 +430,7 @@ impl<'ctx, 'tcx> RenderTerminusContext<'ctx, 'tcx> {
                 self.relative_import_path.clone(),
             ));
 
-        let mut child = MethodDependency::new("".to_string(), type_name.clone());
+        let mut child = MethodDependency::new("".to_string(), Some(param_name));
 
         #[derive(Template)]
         #[template(path = "demo_gen/struct.js.jinja", escape = "none")]