Simplify CB names (#7534)

1. When opening CB with source node, the type name is skipped and only method names are displayed. Fixes #7471
2. When entered Main module of some library, the module names are no longer displayed with their full qualified name.

![image](https://github.com/enso-org/enso/assets/3919101/2d1fe4ad-6391-41d6-89a1-410492457b57)

# Important Notes
Refactoring: I changed the internal representation of `ImString` to `Rc<str>` instead of `Rc<String>` to reduce the number of allocations and memory jumps. I even tried to remove `ImString` altogether, but it was not easy, and the main problem was lacking Default implementation.

app/gui/src/controller/searcher/component.rs

@@ -131,16 +131,8 @@ impl Component {
         id: entry::Id,
         entry: Rc<Entry>,
         group_id: Option<usize>,
+        label: ImString,
     ) -> Self {
-        let label = match entry.kind {
-            entry::Kind::Module
-                if entry.defined_in.is_main_module() || entry.defined_in.is_top_element() =>
-                format!("{}", entry.defined_in).into(),
-            _ => match entry.self_type.as_ref() {
-                Some(self_type) => format!("{}.{}", self_type.alias_name(), entry.name).into(),
-                None => entry.name.to_im_string(),
-            },
-        };
         let aliases =
             entry.aliases().map(|alias| format!("{alias} ({label})").into()).collect_vec().into();
         let data = Suggestion::FromDatabase { id, entry };

app/gui/src/controller/searcher/component/builder.rs

@@ -286,7 +286,16 @@ impl<'a> Builder<'a> {
             None => WhenDisplayed::in_base_mode(&entry, group_id.is_some()),
         };
         let when_displayed = when_displayed.consider_tags(&entry);
-        let component = Component::new_from_database_entry(id, entry, group_id);
+        let label = match entry.kind {
+            suggestion_database::entry::Kind::Module if self.inside_module.is_none() =>
+                format!("{}", entry.defined_in).into(),
+            _ => match entry.self_type.as_ref() {
+                Some(self_type) if self.this_type.is_none() =>
+                    format!("{}.{}", self_type.alias_name(), entry.name).into(),
+                _ => entry.name.to_im_string(),
+            },
+        };
+        let component = Component::new_from_database_entry(id, entry, group_id, label);
         if matches!(when_displayed, WhenDisplayed::Always) {
             self.built_list.displayed_by_default.push(component.clone());
         }
@@ -482,6 +491,35 @@ mod tests {
         ]);
     }
 
+    #[test]
+    fn building_main_module_content_list() {
+        let database = mock_database();
+        let groups = mock_groups();
+        let (module_id, _) = database
+            .lookup_by_qualified_name(&QualifiedName::from_text("test.Test").unwrap())
+            .unwrap();
+        let mut builder = Builder::new_inside_module(&database, &groups, module_id);
+
+        builder.add_components_from_db(database.keys());
+        let list = builder.build();
+
+        check_displayed_components(&list, vec!["TopModule1", "TopModule2"]);
+        check_groups(&list, vec![None, None]);
+        check_filterable_components(&list, vec![
+            "TopModule1",
+            "TopModule1.fun1",
+            "TopModule1.fun2",
+            "SubModule1",
+            "SubModule1.fun4",
+            "SubModule2",
+            "SubModule2.fun5",
+            "SubModule3",
+            "SubModule3.fun6",
+            "TopModule2",
+            "TopModule2.fun0",
+        ]);
+    }
+
 
 
     #[test]

app/gui/src/model/module.rs

@@ -163,7 +163,7 @@ impl Path {
         if let [ref _src, ref dirs @ .., _] = *self.file_path.segments.as_slice() {
             // Path must designate a valid module and must be able to designate any valid module.
             // Therefore, unwraps in this method are safe.
-            let parent_modules = dirs.iter().map(ImString::new).collect();
+            let parent_modules = dirs.iter().map(ImString::from).collect();
             let name = ImString::new(self.module_name());
             Id { parent_modules, name }
         } else {

lib/rust/prelude/src/string.rs

@@ -160,17 +160,16 @@ impl AsRef<str> for CowString {
 // ================
 
 /// Immutable string implementation with a fast clone implementation.
-#[derive(Clone, CloneRef, Default, Eq, Hash, PartialEq, Ord, PartialOrd)]
+#[derive(Clone, CloneRef, Eq, Hash, PartialEq, Ord, PartialOrd)]
 #[derive(Deserialize, Serialize)]
 pub struct ImString {
-    content: Rc<String>,
+    content: Rc<str>,
 }
 
 impl ImString {
     /// Constructor.
-    pub fn new(content: impl Into<String>) -> Self {
+    pub fn new(content: impl Into<Rc<str>>) -> Self {
-        let content = Rc::new(content.into());
+        Self { content: content.into() }
-        Self { content }
     }
 
     /// Extract a string slice containing the entire string.
@@ -179,6 +178,12 @@ impl ImString {
     }
 }
 
+impl Default for ImString {
+    fn default() -> Self {
+        "".into()
+    }
+}
+
 impl std::fmt::Display for ImString {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         std::fmt::Display::fmt(&self.content, f)
@@ -204,12 +209,6 @@ impl AsRef<ImString> for ImString {
     }
 }
 
-impl AsRef<String> for ImString {
-    fn as_ref(&self) -> &String {
-        self.content.as_ref()
-    }
-}
-
 impl AsRef<str> for ImString {
     fn as_ref(&self) -> &str {
         self.content.as_ref()
@@ -222,9 +221,9 @@ impl Borrow<str> for ImString {
     }
 }
 
-impl Borrow<String> for ImString {
+impl From<Rc<str>> for ImString {
-    fn borrow(&self) -> &String {
+    fn from(content: Rc<str>) -> Self {
-        &self.content
+        Self { content }
     }
 }
 
@@ -236,13 +235,13 @@ impl From<String> for ImString {
 
 impl From<&String> for ImString {
     fn from(t: &String) -> Self {
-        Self::new(t)
+        Self::new(t.as_str())
     }
 }
 
 impl From<&&String> for ImString {
     fn from(t: &&String) -> Self {
-        Self::new(*t)
+        Self::new(t.as_str())
     }
 }
 
@@ -264,18 +263,21 @@ impl From<Cow<'_, str>> for ImString {
     }
 }
 
+impl From<ImString> for Rc<str> {
+    fn from(t: ImString) -> Self {
+        t.content
+    }
+}
+
 impl From<ImString> for String {
     fn from(value: ImString) -> Self {
-        match Rc::try_unwrap(value.content) {
+        value.as_str().into()
-            Ok(str) => str,
-            Err(rc) => rc.deref().clone(),
-        }
     }
 }
 
 impl PartialEq<&str> for ImString {
     fn eq(&self, other: &&str) -> bool {
-        self.content.as_ref().eq(other)
+        self.content.as_ref().eq(*other)
     }
 }
 
@@ -287,7 +289,7 @@ impl PartialEq<str> for ImString {
 
 impl PartialEq<ImString> for &str {
     fn eq(&self, other: &ImString) -> bool {
-        self.eq(other.content.as_ref())
+        self.eq(&other.content.as_ref())
     }
 }
 
@@ -410,12 +412,6 @@ macro_rules! im_string_newtype_without_serde {
             }
         }
 
-        impl AsRef<String> for $name {
-            fn as_ref(&self) -> &String {
-                self.content.as_ref()
-            }
-        }
-
         impl AsRef<str> for $name {
             fn as_ref(&self) -> &str {
                 self.content.as_ref()

lib/rust/text/src/text.rs

@@ -942,7 +942,7 @@ impl From<Rope> for String {
 
 impl From<Rope> for ImString {
     fn from(t: Rope) -> Self {
-        ImString::new(t)
+        ImString::new(t.to_im_string())
     }
 }