live preview: Fix thinko leading to wrong elements getting selected

The `SelectedElement` does not need a `debug_index` as the interesting node
is fully specified by the source location it already contains.

tools/lsp/preview.rs

@@ -129,7 +129,6 @@ fn drop_component(
         element_selection::select_element_at_source_code_position(
             path,
             drop_data.selection_offset,
-            drop_data.debug_index,
             is_layout,
             None,
             true,
@@ -421,7 +420,6 @@ pub fn load_preview(preview_component: PreviewComponent) {
             element_selection::select_element_at_source_code_position(
                 se.path.clone(),
                 se.offset,
-                se.debug_index,
                 se.is_layout,
                 None,
                 false,
@@ -558,12 +556,7 @@ pub fn highlight(url: Option<Url>, offset: u32) {
                 let is_layout =
                     e.borrow().debug.get(debug_index).map_or(false, |(_, l)| l.is_some());
                 element_selection::select_element_at_source_code_position(
-                    path,
-                    offset,
-                    debug_index,
-                    is_layout,
-                    None,
-                    false,
+                    path, offset, is_layout, None, false,
                 );
             } else {
                 element_selection::unselect_element();

tools/lsp/preview/drop_location.rs

@@ -81,8 +81,6 @@ pub struct DropData {
     /// The offset to select next. This is different from the insert position
     /// due to indentation, etc.
     pub selection_offset: u32,
-    /// The index into the `debug` vector of the target element.
-    pub debug_index: usize,
 }
 
 /// Find a location in a file that would be a good place to insert the new component at
@@ -152,6 +150,6 @@ pub fn drop_at(
             import_path: if import_path.is_empty() { None } else { Some(import_path) },
             insert_position: drop_info.insertion_position,
         },
-        DropData { selection_offset, debug_index: drop_info.target_element_node.debug_index },
+        DropData { selection_offset },
     ))
 }

tools/lsp/preview/element_selection.rs

@@ -62,7 +62,6 @@ impl ElementRcNode {
 pub struct ElementSelection {
     pub path: PathBuf,
     pub offset: u32,
-    pub debug_index: usize,
     pub instance_index: usize,
     pub is_layout: bool,
 }
@@ -74,6 +73,20 @@ impl ElementSelection {
         let elements = component_instance.element_at_source_code_position(&self.path, self.offset);
         elements.get(self.instance_index).or_else(|| elements.first()).cloned()
     }
+
+    pub fn as_element_node(&self) -> Option<ElementRcNode> {
+        let element = self.as_element()?;
+
+        let debug_index = {
+            let e = element.borrow();
+            e.debug.iter().position(|(n, _)| {
+                n.source_file.path() == &self.path
+                    && u32::from(n.text_range().start()) == self.offset
+            })
+        };
+
+        debug_index.map(|i| ElementRcNode { element, debug_index: i })
+    }
 }
 
 // Look at an element and if it is a sub component, jump to its root_element()
@@ -124,7 +137,6 @@ pub fn unselect_element() {
 pub fn select_element_at_source_code_position(
     path: PathBuf,
     offset: u32,
-    debug_index: usize,
     is_layout: bool,
     position: Option<LogicalPoint>,
     notify_editor_about_selection_after_update: bool,
@@ -136,7 +148,6 @@ pub fn select_element_at_source_code_position(
         &component_instance,
         path,
         offset,
-        debug_index,
         is_layout,
         position,
         notify_editor_about_selection_after_update,
@@ -147,7 +158,6 @@ fn select_element_at_source_code_position_impl(
     component_instance: &ComponentInstance,
     path: PathBuf,
     offset: u32,
-    debug_index: usize,
     is_layout: bool,
     position: Option<LogicalPoint>,
     notify_editor_about_selection_after_update: bool,
@@ -161,7 +171,7 @@ fn select_element_at_source_code_position_impl(
         .unwrap_or_default();
 
     super::set_selected_element(
-        Some(ElementSelection { path, offset, debug_index, instance_index, is_layout }),
+        Some(ElementSelection { path, offset, instance_index, is_layout }),
         positions,
         notify_editor_about_selection_after_update,
     );
@@ -178,7 +188,6 @@ fn select_element_node(
         component_instance,
         path,
         offset,
-        selected_element.debug_index,
         selected_element
             .element
             .borrow()