6 files changed, 93 insertions, 28 deletions

diff --git a/crates/ide_assists/src/handlers/replace_derive_with_manual_impl.rs b/crates/ide_assists/src/handlers/replace_derive_with_manual_impl.rs
index 2608b56da..4f0ef52ca 100644
--- a/crates/ide_assists/src/handlers/replace_derive_with_manual_impl.rs
+++ b/crates/ide_assists/src/handlers/replace_derive_with_manual_impl.rs
@@ -72,7 +72,6 @@ pub(crate) fn replace_derive_with_manual_impl(
         items_locator::AssocItemSearch::Exclude,
         Some(items_locator::DEFAULT_QUERY_SEARCH_LIMIT),
     )
-    .into_iter()
     .filter_map(|item| match ModuleDef::from(item.as_module_def_id()?) {
         ModuleDef::Trait(trait_) => Some(trait_),
         _ => None,
diff --git a/crates/ide_completion/src/completions/flyimport.rs b/crates/ide_completion/src/completions/flyimport.rs
index eb2cba631..1ad017198 100644
--- a/crates/ide_completion/src/completions/flyimport.rs
+++ b/crates/ide_completion/src/completions/flyimport.rs
@@ -1,8 +1,10 @@
 //! Feature: completion with imports-on-the-fly
 //!
 //! When completing names in the current scope, proposes additional imports from other modules or crates,
-//! if they can be qualified in the scope and their name contains all symbols from the completion input
-//! (case-insensitive, in any order or places).
+//! if they can be qualified in the scope and their name contains all symbols from the completion input.
+//!
+//! To be considered applicable, the name must contain all input symbols in the given order, not necessarily adjacent.
+//! If any input symbol is not lowercased, the name must contain all symbols in exact case; otherwise the contaning is checked case-insensitively.
 //!
 //! ```
 //! fn main() {
@@ -942,7 +944,7 @@ mod foo {
 }
 
 fn main() {
-    bar::Ass$0
+    bar::ASS$0
 }"#,
             expect![[]],
         )
@@ -979,4 +981,57 @@ fn main() {
             expect![[]],
         )
     }
+
+    #[test]
+    fn case_matters() {
+        check(
+            r#"
+mod foo {
+    pub const TEST_CONST: usize = 3;
+    pub fn test_function() -> i32 {
+        4
+    }
+}
+
+fn main() {
+    TE$0
+}"#,
+            expect![[r#"
+        ct foo::TEST_CONST
+    "#]],
+        );
+
+        check(
+            r#"
+mod foo {
+    pub const TEST_CONST: usize = 3;
+    pub fn test_function() -> i32 {
+        4
+    }
+}
+
+fn main() {
+    te$0
+}"#,
+            expect![[r#"
+        ct foo::TEST_CONST
+        fn test_function() (foo::test_function) fn() -> i32
+    "#]],
+        );
+
+        check(
+            r#"
+mod foo {
+    pub const TEST_CONST: usize = 3;
+    pub fn test_function() -> i32 {
+        4
+    }
+}
+
+fn main() {
+    Te$0
+}"#,
+            expect![[]],
+        );
+    }
 }
diff --git a/crates/ide_completion/src/lib.rs b/crates/ide_completion/src/lib.rs
index 87cddb98e..5ac1cb48d 100644
--- a/crates/ide_completion/src/lib.rs
+++ b/crates/ide_completion/src/lib.rs
@@ -161,7 +161,6 @@ pub fn resolve_completion_edits(
         items_locator::AssocItemSearch::Include,
         Some(items_locator::DEFAULT_QUERY_SEARCH_LIMIT),
     )
-    .into_iter()
     .filter_map(|candidate| {
         current_module
             .find_use_path_prefixed(db, candidate, config.insert_use.prefix_kind)
diff --git a/crates/ide_db/src/helpers/import_assets.rs b/crates/ide_db/src/helpers/import_assets.rs
index 0da7a1a9d..1881c746f 100644
--- a/crates/ide_db/src/helpers/import_assets.rs
+++ b/crates/ide_db/src/helpers/import_assets.rs
@@ -267,7 +267,6 @@ fn path_applicable_imports(
                 AssocItemSearch::Exclude,
                 Some(DEFAULT_QUERY_SEARCH_LIMIT),
             )
-            .into_iter()
             .filter_map(|item| {
                 let mod_path = mod_path(item)?;
                 Some(LocatedImport::new(mod_path.clone(), item, item, Some(mod_path)))
@@ -285,7 +284,6 @@ fn path_applicable_imports(
                 AssocItemSearch::Include,
                 Some(DEFAULT_QUERY_SEARCH_LIMIT),
             )
-            .into_iter()
             .filter_map(|item| {
                 import_for_item(
                     sema.db,
@@ -430,7 +428,6 @@ fn trait_applicable_items(
         AssocItemSearch::AssocItemsOnly,
         Some(DEFAULT_QUERY_SEARCH_LIMIT),
     )
-    .into_iter()
     .filter_map(|input| item_as_assoc(db, input))
     .filter_map(|assoc| {
         let assoc_item_trait = assoc.containing_trait(db)?;
diff --git a/crates/ide_db/src/items_locator.rs b/crates/ide_db/src/items_locator.rs
index 518cddd74..ef796b6f7 100644
--- a/crates/ide_db/src/items_locator.rs
+++ b/crates/ide_db/src/items_locator.rs
@@ -15,7 +15,6 @@ use crate::{
     symbol_index::{self, FileSymbol},
     RootDatabase,
 };
-use rustc_hash::FxHashSet;
 
 /// A value to use, when uncertain which limit to pick.
 pub const DEFAULT_QUERY_SEARCH_LIMIT: usize = 40;
@@ -32,16 +31,16 @@ pub enum AssocItemSearch {
 }
 
 /// Searches for importable items with the given name in the crate and its dependencies.
-pub fn items_with_name(
-    sema: &Semantics<'_, RootDatabase>,
+pub fn items_with_name<'a>(
+    sema: &'a Semantics<'_, RootDatabase>,
     krate: Crate,
     name: NameToImport,
     assoc_item_search: AssocItemSearch,
     limit: Option<usize>,
-) -> FxHashSet<ItemInNs> {
+) -> impl Iterator<Item = ItemInNs> + 'a {
     let _p = profile::span("items_with_name").detail(|| {
         format!(
-            "Name: {} ({:?}), crate: {:?}, limit: {:?}",
+            "Name: {}, crate: {:?}, assoc items: {:?}, limit: {:?}",
             name.text(),
             assoc_item_search,
             krate.display_name(sema.db).map(|name| name.to_string()),
@@ -62,6 +61,8 @@ pub fn items_with_name(
             (local_query, external_query)
         }
         NameToImport::Fuzzy(fuzzy_search_string) => {
+            let mut local_query = symbol_index::Query::new(fuzzy_search_string.clone());
+
             let mut external_query = import_map::Query::new(fuzzy_search_string.clone())
                 .search_mode(import_map::SearchMode::Fuzzy)
                 .name_only();
@@ -75,7 +76,12 @@ pub fn items_with_name(
                 }
             }
 
-            (symbol_index::Query::new(fuzzy_search_string), external_query)
+            if fuzzy_search_string.to_lowercase() != fuzzy_search_string {
+                local_query.case_sensitive();
+                external_query = external_query.case_sensitive();
+            }
+
+            (local_query, external_query)
         }
     };
 
@@ -87,13 +93,13 @@ pub fn items_with_name(
     find_items(sema, krate, assoc_item_search, local_query, external_query)
 }
 
-fn find_items(
-    sema: &Semantics<'_, RootDatabase>,
+fn find_items<'a>(
+    sema: &'a Semantics<'_, RootDatabase>,
     krate: Crate,
     assoc_item_search: AssocItemSearch,
     local_query: symbol_index::Query,
     external_query: import_map::Query,
-) -> FxHashSet<ItemInNs> {
+) -> impl Iterator<Item = ItemInNs> + 'a {
     let _p = profile::span("find_items");
     let db = sema.db;
 
@@ -108,21 +114,18 @@ fn find_items(
     // Query the local crate using the symbol index.
     let local_results = symbol_index::crate_symbols(db, krate.into(), local_query)
         .into_iter()
-        .filter_map(|local_candidate| get_name_definition(sema, &local_candidate))
+        .filter_map(move |local_candidate| get_name_definition(sema, &local_candidate))
         .filter_map(|name_definition_to_import| match name_definition_to_import {
             Definition::ModuleDef(module_def) => Some(ItemInNs::from(module_def)),
             Definition::Macro(macro_def) => Some(ItemInNs::from(macro_def)),
             _ => None,
         });
 
-    external_importables
-        .chain(local_results)
-        .filter(move |&item| match assoc_item_search {
-            AssocItemSearch::Include => true,
-            AssocItemSearch::Exclude => !is_assoc_item(item, sema.db),
-            AssocItemSearch::AssocItemsOnly => is_assoc_item(item, sema.db),
-        })
-        .collect()
+    external_importables.chain(local_results).filter(move |&item| match assoc_item_search {
+        AssocItemSearch::Include => true,
+        AssocItemSearch::Exclude => !is_assoc_item(item, sema.db),
+        AssocItemSearch::AssocItemsOnly => is_assoc_item(item, sema.db),
+    })
 }
 
 fn get_name_definition(
diff --git a/crates/ide_db/src/symbol_index.rs b/crates/ide_db/src/symbol_index.rs
index 9ed9568ce..35e382b5c 100644
--- a/crates/ide_db/src/symbol_index.rs
+++ b/crates/ide_db/src/symbol_index.rs
@@ -52,6 +52,7 @@ pub struct Query {
     only_types: bool,
     libs: bool,
     exact: bool,
+    case_sensitive: bool,
     limit: usize,
 }
 
@@ -64,6 +65,7 @@ impl Query {
             only_types: false,
             libs: false,
             exact: false,
+            case_sensitive: false,
             limit: usize::max_value(),
         }
     }
@@ -80,6 +82,10 @@ impl Query {
         self.exact = true;
     }
 
+    pub fn case_sensitive(&mut self) {
+        self.case_sensitive = true;
+    }
+
     pub fn limit(&mut self, limit: usize) {
         self.limit = limit
     }
@@ -326,8 +332,14 @@ impl Query {
                     if self.only_types && !symbol.kind.is_type() {
                         continue;
                     }
-                    if self.exact && symbol.name != self.query {
-                        continue;
+                    if self.exact {
+                        if symbol.name != self.query {
+                            continue;
+                        }
+                    } else if self.case_sensitive {
+                        if self.query.chars().any(|c| !symbol.name.contains(c)) {
+                            continue;
+                        }
                     }
 
                     res.push(symbol.clone());