[ivette] Allows a multiple selection of 0 elements.

ivette/src/frama-c/states.ts

@@ -648,10 +648,10 @@ function reducer(s: Selection, action: SelectionActions): Selection {
     return selectLocation(s, action.location);
   }
   if (isMultipleSelect(action)) {
-    if (action.locations.length === 0)
-      return s;
     const index = action.index > 0 ? action.index : 0;
-    const selection = selectLocation(s, action.locations[index]);
+    const selection =
+      action.locations.length === 0 ? s :
+        selectLocation(s, action.locations[index]);
     return {
       ...selection,
       multiple: {

ivette/src/renderer/ASTview.tsx

@@ -87,15 +87,16 @@ async function studia(marker: string, info: markerInfoData, kind: access) {
   const request = kind === 'Reads' ? getReadsLval : getWritesLval;
   const data = await Server.send(request, marker);
   const locations = data.direct.map(([f, m]) => ({ function: f, marker: m }));
+  const lval = info.name;
   if (locations.length > 0) {
-    const lval = info.name;
     const name = `${kind} of ${lval}`;
     const title = `List of statements ${
       (kind === 'Reads') ? 'accessing' : 'modifying'
     } the memory location pointed by ${lval}.`;
     return { name, title, locations, index: 0 };
   }
-  return 'MULTIPLE_CLEAR';
+  const name = `No ${kind.toLowerCase()} of ${lval}`;
+  return { name, title: '', locations: [], index: 0 };
 }
 
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