3 files changed, 194 insertions, 125 deletions

diff --git a/crates/ide_db/src/helpers.rs b/crates/ide_db/src/helpers.rs
index e3e5670f1..c6763ae36 100644
--- a/crates/ide_db/src/helpers.rs
+++ b/crates/ide_db/src/helpers.rs
@@ -38,94 +38,7 @@ pub struct FamousDefs<'a, 'b>(pub &'a Semantics<'b, RootDatabase>, pub Option<Cr
 
 #[allow(non_snake_case)]
 impl FamousDefs<'_, '_> {
-    pub const FIXTURE: &'static str = r#"//- /libcore.rs crate:core
-pub mod convert {
-    pub trait From<T> {
-        fn from(t: T) -> Self;
-    }
-}
-
-pub mod default {
-    pub trait Default {
-       fn default() -> Self;
-    }
-}
-
-pub mod iter {
-    pub use self::traits::{collect::IntoIterator, iterator::Iterator};
-    mod traits {
-        pub(crate) mod iterator {
-            use crate::option::Option;
-            pub trait Iterator {
-                type Item;
-                fn next(&mut self) -> Option<Self::Item>;
-                fn by_ref(&mut self) -> &mut Self {
-                    self
-                }
-                fn take(self, n: usize) -> crate::iter::Take<Self> {
-                    crate::iter::Take { inner: self }
-                }
-            }
-
-            impl<I: Iterator> Iterator for &mut I {
-                type Item = I::Item;
-                fn next(&mut self) -> Option<I::Item> {
-                    (**self).next()
-                }
-            }
-        }
-        pub(crate) mod collect {
-            pub trait IntoIterator {
-                type Item;
-            }
-        }
-    }
-
-    pub use self::sources::*;
-    pub(crate) mod sources {
-        use super::Iterator;
-        use crate::option::Option::{self, *};
-        pub struct Repeat<A> {
-            element: A,
-        }
-
-        pub fn repeat<T>(elt: T) -> Repeat<T> {
-            Repeat { element: elt }
-        }
-
-        impl<A> Iterator for Repeat<A> {
-            type Item = A;
-
-            fn next(&mut self) -> Option<A> {
-                None
-            }
-        }
-    }
-
-    pub use self::adapters::*;
-    pub(crate) mod adapters {
-        use super::Iterator;
-        use crate::option::Option::{self, *};
-        pub struct Take<I> { pub(crate) inner: I }
-        impl<I> Iterator for Take<I> where I: Iterator {
-            type Item = <I as Iterator>::Item;
-            fn next(&mut self) -> Option<<I as Iterator>::Item> {
-                None
-            }
-        }
-    }
-}
-
-pub mod option {
-    pub enum Option<T> { None, Some(T)}
-}
-
-pub mod prelude {
-    pub use crate::{convert::From, iter::{IntoIterator, Iterator}, option::Option::{self, *}, default::Default};
-}
-#[prelude_import]
-pub use prelude::*;
-"#;
+    pub const FIXTURE: &'static str = include_str!("helpers/famous_defs_fixture.rs");
 
     pub fn core(&self) -> Option<Crate> {
         self.find_crate("core")
diff --git a/crates/ide_db/src/helpers/famous_defs_fixture.rs b/crates/ide_db/src/helpers/famous_defs_fixture.rs
new file mode 100644
index 000000000..5e88de64d
--- /dev/null
+++ b/crates/ide_db/src/helpers/famous_defs_fixture.rs
@@ -0,0 +1,120 @@
+//- /libcore.rs crate:core
+//! Signatures of traits, types and functions from the core lib for use in tests.
+pub mod convert {
+    pub trait From<T> {
+        fn from(t: T) -> Self;
+    }
+}
+
+pub mod default {
+    pub trait Default {
+        fn default() -> Self;
+    }
+}
+
+pub mod iter {
+    pub use self::traits::{collect::IntoIterator, iterator::Iterator};
+    mod traits {
+        pub(crate) mod iterator {
+            use crate::option::Option;
+            pub trait Iterator {
+                type Item;
+                fn next(&mut self) -> Option<Self::Item>;
+                fn by_ref(&mut self) -> &mut Self {
+                    self
+                }
+                fn take(self, n: usize) -> crate::iter::Take<Self> {
+                    crate::iter::Take { inner: self }
+                }
+            }
+
+            impl<I: Iterator> Iterator for &mut I {
+                type Item = I::Item;
+                fn next(&mut self) -> Option<I::Item> {
+                    (**self).next()
+                }
+            }
+        }
+        pub(crate) mod collect {
+            pub trait IntoIterator {
+                type Item;
+            }
+        }
+    }
+
+    pub use self::sources::*;
+    pub(crate) mod sources {
+        use super::Iterator;
+        use crate::option::Option::{self, *};
+        pub struct Repeat<A> {
+            element: A,
+        }
+
+        pub fn repeat<T>(elt: T) -> Repeat<T> {
+            Repeat { element: elt }
+        }
+
+        impl<A> Iterator for Repeat<A> {
+            type Item = A;
+
+            fn next(&mut self) -> Option<A> {
+                None
+            }
+        }
+    }
+
+    pub use self::adapters::*;
+    pub(crate) mod adapters {
+        use super::Iterator;
+        use crate::option::Option::{self, *};
+        pub struct Take<I> {
+            pub(crate) inner: I,
+        }
+        impl<I> Iterator for Take<I>
+        where
+            I: Iterator,
+        {
+            type Item = <I as Iterator>::Item;
+            fn next(&mut self) -> Option<<I as Iterator>::Item> {
+                None
+            }
+        }
+    }
+}
+
+pub mod ops {
+    #[lang = "fn"]
+    pub trait Fn<Args>: FnMut<Args> {
+        extern "rust-call" fn call(&self, args: Args) -> Self::Output;
+    }
+
+    #[lang = "fn_mut"]
+    pub trait FnMut<Args>: FnOnce<Args> {
+        extern "rust-call" fn call_mut(&mut self, args: Args) -> Self::Output;
+    }
+    #[lang = "fn_once"]
+    pub trait FnOnce<Args> {
+        #[lang = "fn_once_output"]
+        type Output;
+        extern "rust-call" fn call_once(self, args: Args) -> Self::Output;
+    }
+}
+
+pub mod option {
+    pub enum Option<T> {
+        None,
+        Some(T),
+    }
+}
+
+pub mod prelude {
+    pub use crate::{
+        convert::From,
+        default::Default,
+        iter::{IntoIterator, Iterator},
+        ops::{Fn, FnMut, FnOnce},
+        option::Option::{self, *},
+    };
+}
+#[prelude_import]
+pub use prelude::*;
diff --git a/crates/ide_db/src/search.rs b/crates/ide_db/src/search.rs
index 773bfbc2c..b5fa46642 100644
--- a/crates/ide_db/src/search.rs
+++ b/crates/ide_db/src/search.rs
@@ -18,9 +18,43 @@ use crate::{
     RootDatabase,
 };
 
+#[derive(Debug, Default, Clone)]
+pub struct UsageSearchResult {
+    pub references: FxHashMap<FileId, Vec<FileReference>>,
+}
+
+impl UsageSearchResult {
+    pub fn is_empty(&self) -> bool {
+        self.references.is_empty()
+    }
+
+    pub fn len(&self) -> usize {
+        self.references.len()
+    }
+
+    pub fn iter(&self) -> impl Iterator<Item = (&FileId, &Vec<FileReference>)> + '_ {
+        self.references.iter()
+    }
+
+    pub fn file_ranges(&self) -> impl Iterator<Item = FileRange> + '_ {
+        self.references.iter().flat_map(|(&file_id, refs)| {
+            refs.iter().map(move |&FileReference { range, .. }| FileRange { file_id, range })
+        })
+    }
+}
+
+impl IntoIterator for UsageSearchResult {
+    type Item = (FileId, Vec<FileReference>);
+    type IntoIter = <FxHashMap<FileId, Vec<FileReference>> as IntoIterator>::IntoIter;
+
+    fn into_iter(self) -> Self::IntoIter {
+        self.references.into_iter()
+    }
+}
+
 #[derive(Debug, Clone)]
-pub struct Reference {
-    pub file_range: FileRange,
+pub struct FileReference {
+    pub range: TextRange,
     pub kind: ReferenceKind,
     pub access: Option<ReferenceAccess>,
 }
@@ -252,23 +286,23 @@ impl<'a> FindUsages<'a> {
 
     pub fn at_least_one(self) -> bool {
         let mut found = false;
-        self.search(&mut |_reference| {
+        self.search(&mut |_, _| {
             found = true;
             true
         });
         found
     }
 
-    pub fn all(self) -> Vec<Reference> {
-        let mut res = Vec::new();
-        self.search(&mut |reference| {
-            res.push(reference);
+    pub fn all(self) -> UsageSearchResult {
+        let mut res = UsageSearchResult::default();
+        self.search(&mut |file_id, reference| {
+            res.references.entry(file_id).or_default().push(reference);
             false
         });
         res
     }
 
-    fn search(self, sink: &mut dyn FnMut(Reference) -> bool) {
+    fn search(self, sink: &mut dyn FnMut(FileId, FileReference) -> bool) {
         let _p = profile::span("FindUsages:search");
         let sema = self.sema;
 
@@ -320,16 +354,14 @@ impl<'a> FindUsages<'a> {
     fn found_lifetime(
         &self,
         lifetime: &ast::Lifetime,
-        sink: &mut dyn FnMut(Reference) -> bool,
+        sink: &mut dyn FnMut(FileId, FileReference) -> bool,
     ) -> bool {
         match NameRefClass::classify_lifetime(self.sema, lifetime) {
             Some(NameRefClass::Definition(def)) if &def == self.def => {
-                let reference = Reference {
-                    file_range: self.sema.original_range(lifetime.syntax()),
-                    kind: ReferenceKind::Lifetime,
-                    access: None,
-                };
-                sink(reference)
+                let FileRange { file_id, range } = self.sema.original_range(lifetime.syntax());
+                let reference =
+                    FileReference { range, kind: ReferenceKind::Lifetime, access: None };
+                sink(file_id, reference)
             }
             _ => false, // not a usage
         }
@@ -338,7 +370,7 @@ impl<'a> FindUsages<'a> {
     fn found_name_ref(
         &self,
         name_ref: &ast::NameRef,
-        sink: &mut dyn FnMut(Reference) -> bool,
+        sink: &mut dyn FnMut(FileId, FileReference) -> bool,
     ) -> bool {
         match NameRefClass::classify(self.sema, &name_ref) {
             Some(NameRefClass::Definition(def)) if &def == self.def => {
@@ -352,46 +384,50 @@ impl<'a> FindUsages<'a> {
                     ReferenceKind::Other
                 };
 
-                let reference = Reference {
-                    file_range: self.sema.original_range(name_ref.syntax()),
-                    kind,
-                    access: reference_access(&def, &name_ref),
-                };
-                sink(reference)
+                let FileRange { file_id, range } = self.sema.original_range(name_ref.syntax());
+                let reference =
+                    FileReference { range, kind, access: reference_access(&def, &name_ref) };
+                sink(file_id, reference)
             }
             Some(NameRefClass::FieldShorthand { local_ref: local, field_ref: field }) => {
+                let FileRange { file_id, range } = self.sema.original_range(name_ref.syntax());
                 let reference = match self.def {
-                    Definition::Field(_) if &field == self.def => Reference {
-                        file_range: self.sema.original_range(name_ref.syntax()),
+                    Definition::Field(_) if &field == self.def => FileReference {
+                        range,
                         kind: ReferenceKind::FieldShorthandForField,
                         access: reference_access(&field, &name_ref),
                     },
-                    Definition::Local(l) if &local == l => Reference {
-                        file_range: self.sema.original_range(name_ref.syntax()),
+                    Definition::Local(l) if &local == l => FileReference {
+                        range,
                         kind: ReferenceKind::FieldShorthandForLocal,
                         access: reference_access(&Definition::Local(local), &name_ref),
                     },
                     _ => return false, // not a usage
                 };
-                sink(reference)
+                sink(file_id, reference)
             }
             _ => false, // not a usage
         }
     }
 
-    fn found_name(&self, name: &ast::Name, sink: &mut dyn FnMut(Reference) -> bool) -> bool {
+    fn found_name(
+        &self,
+        name: &ast::Name,
+        sink: &mut dyn FnMut(FileId, FileReference) -> bool,
+    ) -> bool {
         match NameClass::classify(self.sema, name) {
             Some(NameClass::PatFieldShorthand { local_def: _, field_ref }) => {
-                let reference = match self.def {
-                    Definition::Field(_) if &field_ref == self.def => Reference {
-                        file_range: self.sema.original_range(name.syntax()),
-                        kind: ReferenceKind::FieldShorthandForField,
-                        // FIXME: mutable patterns should have `Write` access
-                        access: Some(ReferenceAccess::Read),
-                    },
-                    _ => return false, // not a usage
+                if !matches!(self.def, Definition::Field(_) if &field_ref == self.def) {
+                    return false;
+                }
+                let FileRange { file_id, range } = self.sema.original_range(name.syntax());
+                let reference = FileReference {
+                    range,
+                    kind: ReferenceKind::FieldShorthandForField,
+                    // FIXME: mutable patterns should have `Write` access
+                    access: Some(ReferenceAccess::Read),
                 };
-                sink(reference)
+                sink(file_id, reference)
             }
             _ => false, // not a usage
         }