diff --git a/crates/base_db/src/fixture.rs b/crates/base_db/src/fixture.rs
index 48fa73bf07a..b7286fc7d03 100644
--- a/crates/base_db/src/fixture.rs
+++ b/crates/base_db/src/fixture.rs
@@ -117,13 +117,13 @@ fn test_crate(&self) -> CrateId {
 impl<DB: SourceDatabaseExt + Default + 'static> WithFixture for DB {}
 
 pub struct ChangeFixture {
-    file_position: Option<(FileId, RangeOrOffset)>,
-    files: Vec<FileId>,
-    change: Change,
+    pub file_position: Option<(FileId, RangeOrOffset)>,
+    pub files: Vec<FileId>,
+    pub change: Change,
 }
 
 impl ChangeFixture {
-    fn parse(ra_fixture: &str) -> ChangeFixture {
+    pub fn parse(ra_fixture: &str) -> ChangeFixture {
         let fixture = Fixture::parse(ra_fixture);
         let mut change = Change::new();
 
@@ -132,6 +132,7 @@ fn parse(ra_fixture: &str) -> ChangeFixture {
         let mut crates = FxHashMap::default();
         let mut crate_deps = Vec::new();
         let mut default_crate_root: Option<FileId> = None;
+        let mut default_cfg = CfgOptions::default();
 
         let mut file_set = FileSet::default();
         let source_root_prefix = "/".to_string();
@@ -171,6 +172,7 @@ fn parse(ra_fixture: &str) -> ChangeFixture {
             } else if meta.path == "/main.rs" || meta.path == "/lib.rs" {
                 assert!(default_crate_root.is_none());
                 default_crate_root = Some(file_id);
+                default_cfg = meta.cfg;
             }
 
             change.change_file(file_id, Some(Arc::new(text)));
@@ -185,8 +187,8 @@ fn parse(ra_fixture: &str) -> ChangeFixture {
             crate_graph.add_crate_root(
                 crate_root,
                 Edition::Edition2018,
-                None,
-                CfgOptions::default(),
+                Some("test".to_string()),
+                default_cfg,
                 Env::default(),
                 Default::default(),
             );
diff --git a/crates/ide/src/call_hierarchy.rs b/crates/ide/src/call_hierarchy.rs
index 58e26b94ca7..0fb49de712e 100644
--- a/crates/ide/src/call_hierarchy.rs
+++ b/crates/ide/src/call_hierarchy.rs
@@ -181,8 +181,8 @@ fn caller() {
     call<|>ee();
 }
 "#,
-            "callee FN FileId(1) 0..14 3..9",
-            &["caller FN FileId(1) 15..44 18..24 : [33..39]"],
+            "callee FN FileId(0) 0..14 3..9",
+            &["caller FN FileId(0) 15..44 18..24 : [33..39]"],
             &[],
         );
     }
@@ -197,8 +197,8 @@ fn caller() {
     callee();
 }
 "#,
-            "callee FN FileId(1) 0..14 3..9",
-            &["caller FN FileId(1) 15..44 18..24 : [33..39]"],
+            "callee FN FileId(0) 0..14 3..9",
+            &["caller FN FileId(0) 15..44 18..24 : [33..39]"],
             &[],
         );
     }
@@ -214,8 +214,8 @@ fn caller() {
     callee();
 }
 "#,
-            "callee FN FileId(1) 0..14 3..9",
-            &["caller FN FileId(1) 15..58 18..24 : [33..39, 47..53]"],
+            "callee FN FileId(0) 0..14 3..9",
+            &["caller FN FileId(0) 15..58 18..24 : [33..39, 47..53]"],
             &[],
         );
     }
@@ -234,10 +234,10 @@ fn caller2() {
     callee();
 }
 "#,
-            "callee FN FileId(1) 0..14 3..9",
+            "callee FN FileId(0) 0..14 3..9",
             &[
-                "caller1 FN FileId(1) 15..45 18..25 : [34..40]",
-                "caller2 FN FileId(1) 47..77 50..57 : [66..72]",
+                "caller1 FN FileId(0) 15..45 18..25 : [34..40]",
+                "caller2 FN FileId(0) 47..77 50..57 : [66..72]",
             ],
             &[],
         );
@@ -263,10 +263,10 @@ fn test_caller() {
     }
 }
 "#,
-            "callee FN FileId(1) 0..14 3..9",
+            "callee FN FileId(0) 0..14 3..9",
             &[
-                "caller1 FN FileId(1) 15..45 18..25 : [34..40]",
-                "test_caller FN FileId(1) 95..149 110..121 : [134..140]",
+                "caller1 FN FileId(0) 15..45 18..25 : [34..40]",
+                "test_caller FN FileId(0) 95..149 110..121 : [134..140]",
             ],
             &[],
         );
@@ -287,8 +287,8 @@ fn caller() {
 //- /foo/mod.rs
 pub fn callee() {}
 "#,
-            "callee FN FileId(2) 0..18 7..13",
-            &["caller FN FileId(1) 27..56 30..36 : [45..51]"],
+            "callee FN FileId(1) 0..18 7..13",
+            &["caller FN FileId(0) 27..56 30..36 : [45..51]"],
             &[],
         );
     }
@@ -304,9 +304,9 @@ fn call<|>er() {
     callee();
 }
 "#,
-            "caller FN FileId(1) 15..58 18..24",
+            "caller FN FileId(0) 15..58 18..24",
             &[],
-            &["callee FN FileId(1) 0..14 3..9 : [33..39, 47..53]"],
+            &["callee FN FileId(0) 0..14 3..9 : [33..39, 47..53]"],
         );
     }
 
@@ -325,9 +325,9 @@ fn call<|>er() {
 //- /foo/mod.rs
 pub fn callee() {}
 "#,
-            "caller FN FileId(1) 27..56 30..36",
+            "caller FN FileId(0) 27..56 30..36",
             &[],
-            &["callee FN FileId(2) 0..18 7..13 : [45..51]"],
+            &["callee FN FileId(1) 0..18 7..13 : [45..51]"],
         );
     }
 
@@ -348,9 +348,9 @@ fn caller3() {
 
 }
 "#,
-            "caller2 FN FileId(1) 33..64 36..43",
-            &["caller1 FN FileId(1) 0..31 3..10 : [19..26]"],
-            &["caller3 FN FileId(1) 66..83 69..76 : [52..59]"],
+            "caller2 FN FileId(0) 33..64 36..43",
+            &["caller1 FN FileId(0) 0..31 3..10 : [19..26]"],
+            &["caller3 FN FileId(0) 66..83 69..76 : [52..59]"],
         );
     }
 
@@ -368,9 +368,9 @@ fn main() {
     a<|>()
 }
 "#,
-            "a FN FileId(1) 0..18 3..4",
-            &["main FN FileId(1) 31..52 34..38 : [47..48]"],
-            &["b FN FileId(1) 20..29 23..24 : [13..14]"],
+            "a FN FileId(0) 0..18 3..4",
+            &["main FN FileId(0) 31..52 34..38 : [47..48]"],
+            &["b FN FileId(0) 20..29 23..24 : [13..14]"],
         );
 
         check_hierarchy(
@@ -385,8 +385,8 @@ fn main() {
     a()
 }
 "#,
-            "b FN FileId(1) 20..29 23..24",
-            &["a FN FileId(1) 0..18 3..4 : [13..14]"],
+            "b FN FileId(0) 20..29 23..24",
+            &["a FN FileId(0) 0..18 3..4 : [13..14]"],
             &[],
         );
     }
diff --git a/crates/ide/src/completion/complete_keyword.rs b/crates/ide/src/completion/complete_keyword.rs
index 5645b41fa48..e597470958e 100644
--- a/crates/ide/src/completion/complete_keyword.rs
+++ b/crates/ide/src/completion/complete_keyword.rs
@@ -495,13 +495,13 @@ fn test() {
     fn test_completion_await_impls_future() {
         check(
             r#"
-//- /main.rs
+//- /main.rs crate:main deps:std
 use std::future::*;
 struct A {}
 impl Future for A {}
 fn foo(a: A) { a.<|> }
 
-//- /std/lib.rs
+//- /std/lib.rs crate:std
 pub mod future {
     #[lang = "future_trait"]
     pub trait Future {}
@@ -514,14 +514,14 @@ pub trait Future {}
 
         check(
             r#"
-//- /main.rs
+//- /main.rs crate:main deps:std
 use std::future::*;
 fn foo() {
     let a = async {};
     a.<|>
 }
 
-//- /std/lib.rs
+//- /std/lib.rs crate:std
 pub mod future {
     #[lang = "future_trait"]
     pub trait Future {
diff --git a/crates/ide/src/completion/complete_mod.rs b/crates/ide/src/completion/complete_mod.rs
index 3cfc2e13140..c7a99bdc33d 100644
--- a/crates/ide/src/completion/complete_mod.rs
+++ b/crates/ide/src/completion/complete_mod.rs
@@ -300,7 +300,7 @@ fn baz() {}
     //     "#,
     //         expect![[r#"
     //             md bar;
-    //         "#]],
+    //         "#]],foo
     //     );
     // }
 
@@ -308,7 +308,7 @@ fn baz() {}
     fn already_declared_bin_module_completion_omitted() {
         check(
             r#"
-            //- /src/bin.rs
+            //- /src/bin.rs crate:main
             fn main() {}
             //- /src/bin/foo.rs
             mod <|>
diff --git a/crates/ide/src/completion/complete_qualified_path.rs b/crates/ide/src/completion/complete_qualified_path.rs
index 00e89f0fdf2..2fafedd47c8 100644
--- a/crates/ide/src/completion/complete_qualified_path.rs
+++ b/crates/ide/src/completion/complete_qualified_path.rs
@@ -422,10 +422,10 @@ fn m() fn m()
     fn completes_use_paths_across_crates() {
         check(
             r#"
-//- /main.rs
+//- /main.rs crate:main deps:foo
 use foo::<|>;
 
-//- /foo/lib.rs
+//- /foo/lib.rs crate:foo
 pub mod bar { pub struct S; }
 "#,
             expect![[r#"
diff --git a/crates/ide/src/completion/complete_unqualified_path.rs b/crates/ide/src/completion/complete_unqualified_path.rs
index 8eda4b64d49..2010d9a2fdb 100644
--- a/crates/ide/src/completion/complete_unqualified_path.rs
+++ b/crates/ide/src/completion/complete_unqualified_path.rs
@@ -271,10 +271,10 @@ fn quux() fn quux()
     fn completes_extern_prelude() {
         check(
             r#"
-//- /lib.rs
+//- /lib.rs crate:main deps:other_crate
 use <|>;
 
-//- /other_crate/lib.rs
+//- /other_crate/lib.rs crate:other_crate
 // nothing here
 "#,
             expect![[r#"
@@ -350,10 +350,10 @@ fn completes_self_in_methods() {
     fn completes_prelude() {
         check(
             r#"
-//- /main.rs
+//- /main.rs crate:main deps:std
 fn foo() { let x: <|> }
 
-//- /std/lib.rs
+//- /std/lib.rs crate:std
 #[prelude_import]
 use prelude::*;
 
@@ -371,16 +371,16 @@ fn foo()  fn foo()
     fn completes_std_prelude_if_core_is_defined() {
         check(
             r#"
-//- /main.rs
+//- /main.rs crate:main deps:core,std
 fn foo() { let x: <|> }
 
-//- /core/lib.rs
+//- /core/lib.rs crate:core
 #[prelude_import]
 use prelude::*;
 
 mod prelude { struct Option; }
 
-//- /std/lib.rs
+//- /std/lib.rs crate:std deps:core
 #[prelude_import]
 use prelude::*;
 
diff --git a/crates/ide/src/completion/presentation.rs b/crates/ide/src/completion/presentation.rs
index 987cbfa7a86..a5172b87ece 100644
--- a/crates/ide/src/completion/presentation.rs
+++ b/crates/ide/src/completion/presentation.rs
@@ -1172,9 +1172,9 @@ fn dont_insert_macro_call_parens_unncessary() {
         check_edit(
             "frobnicate!",
             r#"
-//- /main.rs
+//- /main.rs crate:main deps:foo
 use foo::<|>;
-//- /foo/lib.rs
+//- /foo/lib.rs crate:foo
 #[macro_export]
 macro_rules frobnicate { () => () }
 "#,
diff --git a/crates/ide/src/diagnostics.rs b/crates/ide/src/diagnostics.rs
index dc815a48380..906f72a42ab 100644
--- a/crates/ide/src/diagnostics.rs
+++ b/crates/ide/src/diagnostics.rs
@@ -219,7 +219,7 @@ mod tests {
     use test_utils::assert_eq_text;
 
     use crate::{
-        mock_analysis::{analysis_and_position, single_file, MockAnalysis},
+        mock_analysis::{analysis_and_position, many_files, single_file},
         DiagnosticsConfig,
     };
 
@@ -282,9 +282,7 @@ fn check_apply_diagnostic_fix_in_other_file(ra_fixture_before: &str, ra_fixture_
     /// Takes a multi-file input fixture with annotated cursor position and checks that no diagnostics
     /// apply to the file containing the cursor.
     fn check_no_diagnostics(ra_fixture: &str) {
-        let mock = MockAnalysis::with_files(ra_fixture);
-        let files = mock.files().map(|(it, _)| it).collect::<Vec<_>>();
-        let analysis = mock.analysis();
+        let (analysis, files) = many_files(ra_fixture);
         let diagnostics = files
             .into_iter()
             .flat_map(|file_id| {
@@ -304,7 +302,7 @@ fn check_expect(ra_fixture: &str, expect: Expect) {
     fn test_wrap_return_type() {
         check_fix(
             r#"
-//- /main.rs
+//- /main.rs crate:main deps:core
 use core::result::Result::{self, Ok, Err};
 
 fn div(x: i32, y: i32) -> Result<i32, ()> {
@@ -313,7 +311,7 @@ fn div(x: i32, y: i32) -> Result<i32, ()> {
     }
     x / y<|>
 }
-//- /core/lib.rs
+//- /core/lib.rs crate:core
 pub mod result {
     pub enum Result<T, E> { Ok(T), Err(E) }
 }
@@ -335,7 +333,7 @@ fn div(x: i32, y: i32) -> Result<i32, ()> {
     fn test_wrap_return_type_handles_generic_functions() {
         check_fix(
             r#"
-//- /main.rs
+//- /main.rs crate:main deps:core
 use core::result::Result::{self, Ok, Err};
 
 fn div<T>(x: T) -> Result<T, i32> {
@@ -344,7 +342,7 @@ fn div<T>(x: T) -> Result<T, i32> {
     }
     <|>x
 }
-//- /core/lib.rs
+//- /core/lib.rs crate:core
 pub mod result {
     pub enum Result<T, E> { Ok(T), Err(E) }
 }
@@ -366,7 +364,7 @@ fn div<T>(x: T) -> Result<T, i32> {
     fn test_wrap_return_type_handles_type_aliases() {
         check_fix(
             r#"
-//- /main.rs
+//- /main.rs crate:main deps:core
 use core::result::Result::{self, Ok, Err};
 
 type MyResult<T> = Result<T, ()>;
@@ -377,7 +375,7 @@ fn div(x: i32, y: i32) -> MyResult<i32> {
     }
     x <|>/ y
 }
-//- /core/lib.rs
+//- /core/lib.rs crate:core
 pub mod result {
     pub enum Result<T, E> { Ok(T), Err(E) }
 }
@@ -401,12 +399,12 @@ fn div(x: i32, y: i32) -> MyResult<i32> {
     fn test_wrap_return_type_not_applicable_when_expr_type_does_not_match_ok_type() {
         check_no_diagnostics(
             r#"
-//- /main.rs
+//- /main.rs crate:main deps:core
 use core::result::Result::{self, Ok, Err};
 
 fn foo() -> Result<(), i32> { 0 }
 
-//- /core/lib.rs
+//- /core/lib.rs crate:core
 pub mod result {
     pub enum Result<T, E> { Ok(T), Err(E) }
 }
@@ -418,14 +416,14 @@ pub enum Result<T, E> { Ok(T), Err(E) }
     fn test_wrap_return_type_not_applicable_when_return_type_is_not_result() {
         check_no_diagnostics(
             r#"
-//- /main.rs
+//- /main.rs crate:main deps:core
 use core::result::Result::{self, Ok, Err};
 
 enum SomeOtherEnum { Ok(i32), Err(String) }
 
 fn foo() -> SomeOtherEnum { 0 }
 
-//- /core/lib.rs
+//- /core/lib.rs crate:core
 pub mod result {
     pub enum Result<T, E> { Ok(T), Err(E) }
 }
@@ -567,7 +565,7 @@ fn test_unresolved_module_diagnostic() {
                                     file_system_edits: [
                                         CreateFile {
                                             anchor: FileId(
-                                                1,
+                                                0,
                                             ),
                                             dst: "foo.rs",
                                         },
diff --git a/crates/ide/src/display/navigation_target.rs b/crates/ide/src/display/navigation_target.rs
index 1ee80c2dd4e..bace2f3a370 100644
--- a/crates/ide/src/display/navigation_target.rs
+++ b/crates/ide/src/display/navigation_target.rs
@@ -439,7 +439,7 @@ fn foo() { enum FooInner { } }
             [
                 NavigationTarget {
                     file_id: FileId(
-                        1,
+                        0,
                     ),
                     full_range: 0..17,
                     focus_range: Some(
@@ -455,7 +455,7 @@ fn foo() { enum FooInner { } }
                 },
                 NavigationTarget {
                     file_id: FileId(
-                        1,
+                        0,
                     ),
                     full_range: 29..46,
                     focus_range: Some(
diff --git a/crates/ide/src/goto_definition.rs b/crates/ide/src/goto_definition.rs
index 15e9b7fad82..5fd2d1e9aca 100644
--- a/crates/ide/src/goto_definition.rs
+++ b/crates/ide/src/goto_definition.rs
@@ -103,12 +103,11 @@ mod tests {
     use base_db::FileRange;
     use syntax::{TextRange, TextSize};
 
-    use crate::mock_analysis::MockAnalysis;
+    use crate::mock_analysis::analysis_and_annotations;
 
     fn check(ra_fixture: &str) {
-        let (mock, position) = MockAnalysis::with_files_and_position(ra_fixture);
-        let (mut expected, data) = mock.annotation();
-        let analysis = mock.analysis();
+        let (analysis, position, mut annotations) = analysis_and_annotations(ra_fixture);
+        let (mut expected, data) = annotations.pop().unwrap();
         match data.as_str() {
             "" => (),
             "file" => {
@@ -133,9 +132,9 @@ fn check(ra_fixture: &str) {
     fn goto_def_for_extern_crate() {
         check(
             r#"
-            //- /main.rs
+            //- /main.rs crate:main deps:std
             extern crate std<|>;
-            //- /std/lib.rs
+            //- /std/lib.rs crate:std
             // empty
             //^ file
             "#,
@@ -146,9 +145,9 @@ fn goto_def_for_extern_crate() {
     fn goto_def_for_renamed_extern_crate() {
         check(
             r#"
-            //- /main.rs
+            //- /main.rs crate:main deps:std
             extern crate std as abc<|>;
-            //- /std/lib.rs
+            //- /std/lib.rs crate:std
             // empty
             //^ file
             "#,
@@ -342,10 +341,10 @@ fn bar() {
     fn goto_def_for_use_alias() {
         check(
             r#"
-//- /lib.rs
+//- /lib.rs crate:main deps:foo
 use foo as bar<|>;
 
-//- /foo/lib.rs
+//- /foo/lib.rs crate:foo
 // empty
 //^ file
 "#,
@@ -356,10 +355,10 @@ fn goto_def_for_use_alias() {
     fn goto_def_for_use_alias_foo_macro() {
         check(
             r#"
-//- /lib.rs
+//- /lib.rs crate:main deps:foo
 use foo::foo as bar<|>;
 
-//- /foo/lib.rs
+//- /foo/lib.rs crate:foo
 #[macro_export]
 macro_rules! foo { () => { () } }
            //^^^
@@ -371,7 +370,6 @@ macro_rules! foo { () => { () } }
     fn goto_def_for_methods() {
         check(
             r#"
-//- /lib.rs
 struct Foo;
 impl Foo {
     fn frobnicate(&self) { }
diff --git a/crates/ide/src/goto_implementation.rs b/crates/ide/src/goto_implementation.rs
index f503f4ec5fe..a88854d05c4 100644
--- a/crates/ide/src/goto_implementation.rs
+++ b/crates/ide/src/goto_implementation.rs
@@ -76,12 +76,10 @@ fn impls_for_trait(
 mod tests {
     use base_db::FileRange;
 
-    use crate::mock_analysis::MockAnalysis;
+    use crate::mock_analysis::analysis_and_annotations;
 
     fn check(ra_fixture: &str) {
-        let (mock, position) = MockAnalysis::with_files_and_position(ra_fixture);
-        let annotations = mock.annotations();
-        let analysis = mock.analysis();
+        let (analysis, position, annotations) = analysis_and_annotations(ra_fixture);
 
         let navs = analysis.goto_implementation(position).unwrap().unwrap().info;
 
diff --git a/crates/ide/src/goto_type_definition.rs b/crates/ide/src/goto_type_definition.rs
index 4a151b15064..b55a2dbb1a5 100644
--- a/crates/ide/src/goto_type_definition.rs
+++ b/crates/ide/src/goto_type_definition.rs
@@ -56,13 +56,12 @@ fn priority(n: &SyntaxToken) -> usize {
 mod tests {
     use base_db::FileRange;
 
-    use crate::mock_analysis::MockAnalysis;
+    use crate::mock_analysis::analysis_and_annotations;
 
     fn check(ra_fixture: &str) {
-        let (mock, position) = MockAnalysis::with_files_and_position(ra_fixture);
-        let (expected, data) = mock.annotation();
+        let (analysis, position, mut annotations) = analysis_and_annotations(ra_fixture);
+        let (expected, data) = annotations.pop().unwrap();
         assert!(data.is_empty());
-        let analysis = mock.analysis();
 
         let mut navs = analysis.goto_type_definition(position).unwrap().unwrap().info;
         assert_eq!(navs.len(), 1);
diff --git a/crates/ide/src/hover.rs b/crates/ide/src/hover.rs
index bb9f12cd37e..008061a3975 100644
--- a/crates/ide/src/hover.rs
+++ b/crates/ide/src/hover.rs
@@ -1275,7 +1275,7 @@ fn test_hover_trait_show_qualifiers() {
                     Implementaion(
                         FilePosition {
                             file_id: FileId(
-                                1,
+                                0,
                             ),
                             offset: 13,
                         },
@@ -1289,9 +1289,9 @@ fn test_hover_trait_show_qualifiers() {
     fn test_hover_extern_crate() {
         check(
             r#"
-//- /main.rs
+//- /main.rs crate:main deps:std
 extern crate st<|>d;
-//- /std/lib.rs
+//- /std/lib.rs crate:std
 //! Standard library for this test
 //!
 //! Printed?
@@ -1307,9 +1307,9 @@ fn test_hover_extern_crate() {
         );
         check(
             r#"
-//- /main.rs
+//- /main.rs crate:main deps:std
 extern crate std as ab<|>c;
-//- /std/lib.rs
+//- /std/lib.rs crate:std
 //! Standard library for this test
 //!
 //! Printed?
@@ -1989,7 +1989,7 @@ fn test_hover_trait_has_impl_action() {
                     Implementaion(
                         FilePosition {
                             file_id: FileId(
-                                1,
+                                0,
                             ),
                             offset: 6,
                         },
@@ -2008,7 +2008,7 @@ fn test_hover_struct_has_impl_action() {
                     Implementaion(
                         FilePosition {
                             file_id: FileId(
-                                1,
+                                0,
                             ),
                             offset: 7,
                         },
@@ -2027,7 +2027,7 @@ fn test_hover_union_has_impl_action() {
                     Implementaion(
                         FilePosition {
                             file_id: FileId(
-                                1,
+                                0,
                             ),
                             offset: 6,
                         },
@@ -2046,7 +2046,7 @@ fn test_hover_enum_has_impl_action() {
                     Implementaion(
                         FilePosition {
                             file_id: FileId(
-                                1,
+                                0,
                             ),
                             offset: 5,
                         },
@@ -2069,7 +2069,7 @@ fn foo_<|>test() {}
                         Runnable {
                             nav: NavigationTarget {
                                 file_id: FileId(
-                                    1,
+                                    0,
                                 ),
                                 full_range: 0..24,
                                 focus_range: Some(
@@ -2112,7 +2112,7 @@ fn foo_test() {}
                         Runnable {
                             nav: NavigationTarget {
                                 file_id: FileId(
-                                    1,
+                                    0,
                                 ),
                                 full_range: 0..46,
                                 focus_range: Some(
@@ -2151,7 +2151,7 @@ struct S{ f1: u32 }
                                 mod_path: "test::S",
                                 nav: NavigationTarget {
                                     file_id: FileId(
-                                        1,
+                                        0,
                                     ),
                                     full_range: 0..19,
                                     focus_range: Some(
@@ -2190,7 +2190,7 @@ struct S<T>{ f1: T }
                                 mod_path: "test::S",
                                 nav: NavigationTarget {
                                     file_id: FileId(
-                                        1,
+                                        0,
                                     ),
                                     full_range: 17..37,
                                     focus_range: Some(
@@ -2209,7 +2209,7 @@ struct S<T>{ f1: T }
                                 mod_path: "test::Arg",
                                 nav: NavigationTarget {
                                     file_id: FileId(
-                                        1,
+                                        0,
                                     ),
                                     full_range: 0..16,
                                     focus_range: Some(
@@ -2248,7 +2248,7 @@ struct S<T>{ f1: T }
                                 mod_path: "test::S",
                                 nav: NavigationTarget {
                                     file_id: FileId(
-                                        1,
+                                        0,
                                     ),
                                     full_range: 17..37,
                                     focus_range: Some(
@@ -2267,7 +2267,7 @@ struct S<T>{ f1: T }
                                 mod_path: "test::Arg",
                                 nav: NavigationTarget {
                                     file_id: FileId(
-                                        1,
+                                        0,
                                     ),
                                     full_range: 0..16,
                                     focus_range: Some(
@@ -2309,7 +2309,7 @@ mod M {
                                 mod_path: "test::A",
                                 nav: NavigationTarget {
                                     file_id: FileId(
-                                        1,
+                                        0,
                                     ),
                                     full_range: 0..14,
                                     focus_range: Some(
@@ -2328,7 +2328,7 @@ mod M {
                                 mod_path: "test::B",
                                 nav: NavigationTarget {
                                     file_id: FileId(
-                                        1,
+                                        0,
                                     ),
                                     full_range: 15..29,
                                     focus_range: Some(
@@ -2347,7 +2347,7 @@ mod M {
                                 mod_path: "test::M::C",
                                 nav: NavigationTarget {
                                     file_id: FileId(
-                                        1,
+                                        0,
                                     ),
                                     full_range: 42..60,
                                     focus_range: Some(
@@ -2386,7 +2386,7 @@ fn foo() -> impl Foo {}
                                 mod_path: "test::Foo",
                                 nav: NavigationTarget {
                                     file_id: FileId(
-                                        1,
+                                        0,
                                     ),
                                     full_range: 0..12,
                                     focus_range: Some(
@@ -2426,7 +2426,7 @@ fn foo() -> impl Foo<S> {}
                                 mod_path: "test::Foo",
                                 nav: NavigationTarget {
                                     file_id: FileId(
-                                        1,
+                                        0,
                                     ),
                                     full_range: 0..15,
                                     focus_range: Some(
@@ -2445,7 +2445,7 @@ fn foo() -> impl Foo<S> {}
                                 mod_path: "test::S",
                                 nav: NavigationTarget {
                                     file_id: FileId(
-                                        1,
+                                        0,
                                     ),
                                     full_range: 16..25,
                                     focus_range: Some(
@@ -2485,7 +2485,7 @@ fn foo() -> impl Foo + Bar {}
                                 mod_path: "test::Foo",
                                 nav: NavigationTarget {
                                     file_id: FileId(
-                                        1,
+                                        0,
                                     ),
                                     full_range: 0..12,
                                     focus_range: Some(
@@ -2504,7 +2504,7 @@ fn foo() -> impl Foo + Bar {}
                                 mod_path: "test::Bar",
                                 nav: NavigationTarget {
                                     file_id: FileId(
-                                        1,
+                                        0,
                                     ),
                                     full_range: 13..25,
                                     focus_range: Some(
@@ -2547,7 +2547,7 @@ fn foo() -> impl Foo<S1> + Bar<S2> {}
                                 mod_path: "test::Foo",
                                 nav: NavigationTarget {
                                     file_id: FileId(
-                                        1,
+                                        0,
                                     ),
                                     full_range: 0..15,
                                     focus_range: Some(
@@ -2566,7 +2566,7 @@ fn foo() -> impl Foo<S1> + Bar<S2> {}
                                 mod_path: "test::Bar",
                                 nav: NavigationTarget {
                                     file_id: FileId(
-                                        1,
+                                        0,
                                     ),
                                     full_range: 16..31,
                                     focus_range: Some(
@@ -2585,7 +2585,7 @@ fn foo() -> impl Foo<S1> + Bar<S2> {}
                                 mod_path: "test::S1",
                                 nav: NavigationTarget {
                                     file_id: FileId(
-                                        1,
+                                        0,
                                     ),
                                     full_range: 32..44,
                                     focus_range: Some(
@@ -2604,7 +2604,7 @@ fn foo() -> impl Foo<S1> + Bar<S2> {}
                                 mod_path: "test::S2",
                                 nav: NavigationTarget {
                                     file_id: FileId(
-                                        1,
+                                        0,
                                     ),
                                     full_range: 45..57,
                                     focus_range: Some(
@@ -2641,7 +2641,7 @@ fn foo(ar<|>g: &impl Foo) {}
                                 mod_path: "test::Foo",
                                 nav: NavigationTarget {
                                     file_id: FileId(
-                                        1,
+                                        0,
                                     ),
                                     full_range: 0..12,
                                     focus_range: Some(
@@ -2681,7 +2681,7 @@ fn foo(ar<|>g: &impl Foo + Bar<S>) {}
                                 mod_path: "test::Foo",
                                 nav: NavigationTarget {
                                     file_id: FileId(
-                                        1,
+                                        0,
                                     ),
                                     full_range: 0..12,
                                     focus_range: Some(
@@ -2700,7 +2700,7 @@ fn foo(ar<|>g: &impl Foo + Bar<S>) {}
                                 mod_path: "test::Bar",
                                 nav: NavigationTarget {
                                     file_id: FileId(
-                                        1,
+                                        0,
                                     ),
                                     full_range: 13..28,
                                     focus_range: Some(
@@ -2719,7 +2719,7 @@ fn foo(ar<|>g: &impl Foo + Bar<S>) {}
                                 mod_path: "test::S",
                                 nav: NavigationTarget {
                                     file_id: FileId(
-                                        1,
+                                        0,
                                     ),
                                     full_range: 29..39,
                                     focus_range: Some(
@@ -2764,7 +2764,7 @@ mod future {
                                 mod_path: "test::future::Future",
                                 nav: NavigationTarget {
                                     file_id: FileId(
-                                        1,
+                                        0,
                                     ),
                                     full_range: 101..163,
                                     focus_range: Some(
@@ -2783,7 +2783,7 @@ mod future {
                                 mod_path: "test::S",
                                 nav: NavigationTarget {
                                     file_id: FileId(
-                                        1,
+                                        0,
                                     ),
                                     full_range: 0..9,
                                     focus_range: Some(
@@ -2821,7 +2821,7 @@ fn foo(ar<|>g: &impl Foo<S>) {}
                                 mod_path: "test::Foo",
                                 nav: NavigationTarget {
                                     file_id: FileId(
-                                        1,
+                                        0,
                                     ),
                                     full_range: 0..15,
                                     focus_range: Some(
@@ -2840,7 +2840,7 @@ fn foo(ar<|>g: &impl Foo<S>) {}
                                 mod_path: "test::S",
                                 nav: NavigationTarget {
                                     file_id: FileId(
-                                        1,
+                                        0,
                                     ),
                                     full_range: 16..27,
                                     focus_range: Some(
@@ -2883,7 +2883,7 @@ fn foo() -> B<dyn Foo> {}
                                 mod_path: "test::B",
                                 nav: NavigationTarget {
                                     file_id: FileId(
-                                        1,
+                                        0,
                                     ),
                                     full_range: 42..55,
                                     focus_range: Some(
@@ -2902,7 +2902,7 @@ fn foo() -> B<dyn Foo> {}
                                 mod_path: "test::Foo",
                                 nav: NavigationTarget {
                                     file_id: FileId(
-                                        1,
+                                        0,
                                     ),
                                     full_range: 0..12,
                                     focus_range: Some(
@@ -2939,7 +2939,7 @@ fn foo(ar<|>g: &dyn Foo) {}
                                 mod_path: "test::Foo",
                                 nav: NavigationTarget {
                                     file_id: FileId(
-                                        1,
+                                        0,
                                     ),
                                     full_range: 0..12,
                                     focus_range: Some(
@@ -2977,7 +2977,7 @@ fn foo(ar<|>g: &dyn Foo<S>) {}
                                 mod_path: "test::Foo",
                                 nav: NavigationTarget {
                                     file_id: FileId(
-                                        1,
+                                        0,
                                     ),
                                     full_range: 0..15,
                                     focus_range: Some(
@@ -2996,7 +2996,7 @@ fn foo(ar<|>g: &dyn Foo<S>) {}
                                 mod_path: "test::S",
                                 nav: NavigationTarget {
                                     file_id: FileId(
-                                        1,
+                                        0,
                                     ),
                                     full_range: 16..27,
                                     focus_range: Some(
@@ -3037,7 +3037,7 @@ fn foo(a<|>rg: &impl ImplTrait<B<dyn DynTrait<B<S>>>>) {}
                                 mod_path: "test::ImplTrait",
                                 nav: NavigationTarget {
                                     file_id: FileId(
-                                        1,
+                                        0,
                                     ),
                                     full_range: 0..21,
                                     focus_range: Some(
@@ -3056,7 +3056,7 @@ fn foo(a<|>rg: &impl ImplTrait<B<dyn DynTrait<B<S>>>>) {}
                                 mod_path: "test::B",
                                 nav: NavigationTarget {
                                     file_id: FileId(
-                                        1,
+                                        0,
                                     ),
                                     full_range: 43..57,
                                     focus_range: Some(
@@ -3075,7 +3075,7 @@ fn foo(a<|>rg: &impl ImplTrait<B<dyn DynTrait<B<S>>>>) {}
                                 mod_path: "test::DynTrait",
                                 nav: NavigationTarget {
                                     file_id: FileId(
-                                        1,
+                                        0,
                                     ),
                                     full_range: 22..42,
                                     focus_range: Some(
@@ -3094,7 +3094,7 @@ fn foo(a<|>rg: &impl ImplTrait<B<dyn DynTrait<B<S>>>>) {}
                                 mod_path: "test::S",
                                 nav: NavigationTarget {
                                     file_id: FileId(
-                                        1,
+                                        0,
                                     ),
                                     full_range: 58..69,
                                     focus_range: Some(
@@ -3142,7 +3142,7 @@ fn test() -> impl Foo { S {} }
                                 mod_path: "test::Foo",
                                 nav: NavigationTarget {
                                     file_id: FileId(
-                                        1,
+                                        0,
                                     ),
                                     full_range: 0..62,
                                     focus_range: Some(
diff --git a/crates/ide/src/mock_analysis.rs b/crates/ide/src/mock_analysis.rs
index 6812db9b97b..8385475993e 100644
--- a/crates/ide/src/mock_analysis.rs
+++ b/crates/ide/src/mock_analysis.rs
@@ -1,174 +1,73 @@
 //! FIXME: write short doc here
-use std::sync::Arc;
 
-use base_db::{CrateName, FileSet, SourceRoot, VfsPath};
-use cfg::CfgOptions;
-use test_utils::{
-    extract_annotations, extract_range_or_offset, Fixture, RangeOrOffset, CURSOR_MARKER,
-};
+use base_db::fixture::ChangeFixture;
+use test_utils::{extract_annotations, RangeOrOffset};
 
-use crate::{Analysis, AnalysisHost, Change, CrateGraph, Edition, FileId, FilePosition, FileRange};
-
-/// Mock analysis is used in test to bootstrap an AnalysisHost/Analysis
-/// from a set of in-memory files.
-#[derive(Debug, Default)]
-pub(crate) struct MockAnalysis {
-    files: Vec<Fixture>,
-}
-
-impl MockAnalysis {
-    /// Creates `MockAnalysis` using a fixture data in the following format:
-    ///
-    /// ```not_rust
-    /// //- /main.rs
-    /// mod foo;
-    /// fn main() {}
-    ///
-    /// //- /foo.rs
-    /// struct Baz;
-    /// ```
-    pub(crate) fn with_files(ra_fixture: &str) -> MockAnalysis {
-        let (res, pos) = MockAnalysis::with_fixture(ra_fixture);
-        assert!(pos.is_none());
-        res
-    }
-
-    /// Same as `with_files`, but requires that a single file contains a `<|>` marker,
-    /// whose position is also returned.
-    pub(crate) fn with_files_and_position(fixture: &str) -> (MockAnalysis, FilePosition) {
-        let (res, position) = MockAnalysis::with_fixture(fixture);
-        let (file_id, range_or_offset) = position.expect("expected a marker (<|>)");
-        let offset = match range_or_offset {
-            RangeOrOffset::Range(_) => panic!(),
-            RangeOrOffset::Offset(it) => it,
-        };
-        (res, FilePosition { file_id, offset })
-    }
-
-    fn with_fixture(fixture: &str) -> (MockAnalysis, Option<(FileId, RangeOrOffset)>) {
-        let mut position = None;
-        let mut res = MockAnalysis::default();
-        for mut entry in Fixture::parse(fixture) {
-            if entry.text.contains(CURSOR_MARKER) {
-                assert!(position.is_none(), "only one marker (<|>) per fixture is allowed");
-                let (range_or_offset, text) = extract_range_or_offset(&entry.text);
-                entry.text = text;
-                let file_id = res.add_file_fixture(entry);
-                position = Some((file_id, range_or_offset));
-            } else {
-                res.add_file_fixture(entry);
-            }
-        }
-        (res, position)
-    }
-
-    fn add_file_fixture(&mut self, fixture: Fixture) -> FileId {
-        let file_id = FileId((self.files.len() + 1) as u32);
-        self.files.push(fixture);
-        file_id
-    }
-
-    pub(crate) fn id_of(&self, path: &str) -> FileId {
-        let (file_id, _) =
-            self.files().find(|(_, data)| path == data.path).expect("no file in this mock");
-        file_id
-    }
-    pub(crate) fn annotations(&self) -> Vec<(FileRange, String)> {
-        self.files()
-            .flat_map(|(file_id, fixture)| {
-                let annotations = extract_annotations(&fixture.text);
-                annotations
-                    .into_iter()
-                    .map(move |(range, data)| (FileRange { file_id, range }, data))
-            })
-            .collect()
-    }
-    pub(crate) fn files(&self) -> impl Iterator<Item = (FileId, &Fixture)> + '_ {
-        self.files.iter().enumerate().map(|(idx, fixture)| (FileId(idx as u32 + 1), fixture))
-    }
-    pub(crate) fn annotation(&self) -> (FileRange, String) {
-        let mut all = self.annotations();
-        assert_eq!(all.len(), 1);
-        all.pop().unwrap()
-    }
-    pub(crate) fn analysis_host(self) -> AnalysisHost {
-        let mut host = AnalysisHost::default();
-        let mut change = Change::new();
-        let mut file_set = FileSet::default();
-        let mut crate_graph = CrateGraph::default();
-        let mut root_crate = None;
-        for (i, data) in self.files.into_iter().enumerate() {
-            let path = data.path;
-            assert!(path.starts_with('/'));
-
-            let mut cfg = CfgOptions::default();
-            data.cfg_atoms.iter().for_each(|it| cfg.insert_atom(it.into()));
-            data.cfg_key_values.iter().for_each(|(k, v)| cfg.insert_key_value(k.into(), v.into()));
-            let edition: Edition =
-                data.edition.and_then(|it| it.parse().ok()).unwrap_or(Edition::Edition2018);
-
-            let file_id = FileId(i as u32 + 1);
-            let env = data.env.into_iter().collect();
-            if path == "/lib.rs" || path == "/main.rs" {
-                root_crate = Some(crate_graph.add_crate_root(
-                    file_id,
-                    edition,
-                    Some("test".to_string()),
-                    cfg,
-                    env,
-                    Default::default(),
-                ));
-            } else if path.ends_with("/lib.rs") {
-                let base = &path[..path.len() - "/lib.rs".len()];
-                let crate_name = &base[base.rfind('/').unwrap() + '/'.len_utf8()..];
-                let other_crate = crate_graph.add_crate_root(
-                    file_id,
-                    edition,
-                    Some(crate_name.to_string()),
-                    cfg,
-                    env,
-                    Default::default(),
-                );
-                if let Some(root_crate) = root_crate {
-                    crate_graph
-                        .add_dep(root_crate, CrateName::new(crate_name).unwrap(), other_crate)
-                        .unwrap();
-                }
-            }
-            let path = VfsPath::new_virtual_path(path.to_string());
-            file_set.insert(file_id, path);
-            change.change_file(file_id, Some(Arc::new(data.text).to_owned()));
-        }
-        change.set_crate_graph(crate_graph);
-        change.set_roots(vec![SourceRoot::new_local(file_set)]);
-        host.apply_change(change);
-        host
-    }
-    pub(crate) fn analysis(self) -> Analysis {
-        self.analysis_host().analysis()
-    }
-}
+use crate::{Analysis, AnalysisHost, FileId, FilePosition, FileRange};
 
 /// Creates analysis from a multi-file fixture, returns positions marked with <|>.
 pub(crate) fn analysis_and_position(ra_fixture: &str) -> (Analysis, FilePosition) {
-    let (mock, position) = MockAnalysis::with_files_and_position(ra_fixture);
-    (mock.analysis(), position)
+    let mut host = AnalysisHost::default();
+    let change_fixture = ChangeFixture::parse(ra_fixture);
+    host.db.apply_change(change_fixture.change);
+    let (file_id, range_or_offset) = change_fixture.file_position.expect("expected a marker (<|>)");
+    let offset = match range_or_offset {
+        RangeOrOffset::Range(_) => panic!(),
+        RangeOrOffset::Offset(it) => it,
+    };
+    (host.analysis(), FilePosition { file_id, offset })
 }
 
 /// Creates analysis for a single file.
 pub(crate) fn single_file(ra_fixture: &str) -> (Analysis, FileId) {
-    let mock = MockAnalysis::with_files(ra_fixture);
-    let file_id = mock.id_of("/main.rs");
-    (mock.analysis(), file_id)
+    let mut host = AnalysisHost::default();
+    let change_fixture = ChangeFixture::parse(ra_fixture);
+    host.db.apply_change(change_fixture.change);
+    (host.analysis(), change_fixture.files[0])
+}
+
+/// Creates analysis for a single file.
+pub(crate) fn many_files(ra_fixture: &str) -> (Analysis, Vec<FileId>) {
+    let mut host = AnalysisHost::default();
+    let change_fixture = ChangeFixture::parse(ra_fixture);
+    host.db.apply_change(change_fixture.change);
+    (host.analysis(), change_fixture.files)
 }
 
 /// Creates analysis for a single file, returns range marked with a pair of <|>.
 pub(crate) fn analysis_and_range(ra_fixture: &str) -> (Analysis, FileRange) {
-    let (res, position) = MockAnalysis::with_fixture(ra_fixture);
-    let (file_id, range_or_offset) = position.expect("expected a marker (<|>)");
+    let mut host = AnalysisHost::default();
+    let change_fixture = ChangeFixture::parse(ra_fixture);
+    host.db.apply_change(change_fixture.change);
+    let (file_id, range_or_offset) = change_fixture.file_position.expect("expected a marker (<|>)");
     let range = match range_or_offset {
         RangeOrOffset::Range(it) => it,
         RangeOrOffset::Offset(_) => panic!(),
     };
-    (res.analysis(), FileRange { file_id, range })
+    (host.analysis(), FileRange { file_id, range })
+}
+
+/// Creates analysis from a multi-file fixture, returns positions marked with <|>.
+pub(crate) fn analysis_and_annotations(
+    ra_fixture: &str,
+) -> (Analysis, FilePosition, Vec<(FileRange, String)>) {
+    let mut host = AnalysisHost::default();
+    let change_fixture = ChangeFixture::parse(ra_fixture);
+    host.db.apply_change(change_fixture.change);
+    let (file_id, range_or_offset) = change_fixture.file_position.expect("expected a marker (<|>)");
+    let offset = match range_or_offset {
+        RangeOrOffset::Range(_) => panic!(),
+        RangeOrOffset::Offset(it) => it,
+    };
+
+    let annotations = change_fixture
+        .files
+        .iter()
+        .flat_map(|&file_id| {
+            let file_text = host.analysis().file_text(file_id).unwrap();
+            let annotations = extract_annotations(&file_text);
+            annotations.into_iter().map(move |(range, data)| (FileRange { file_id, range }, data))
+        })
+        .collect();
+    (host.analysis(), FilePosition { file_id, offset }, annotations)
 }
diff --git a/crates/ide/src/parent_module.rs b/crates/ide/src/parent_module.rs
index 68b107901f8..25345447642 100644
--- a/crates/ide/src/parent_module.rs
+++ b/crates/ide/src/parent_module.rs
@@ -63,15 +63,9 @@ pub(crate) fn crate_for(db: &RootDatabase, file_id: FileId) -> Vec<CrateId> {
 
 #[cfg(test)]
 mod tests {
-    use base_db::Env;
-    use cfg::CfgOptions;
     use test_utils::mark;
 
-    use crate::{
-        mock_analysis::{analysis_and_position, MockAnalysis},
-        Change, CrateGraph,
-        Edition::Edition2018,
-    };
+    use crate::mock_analysis::{analysis_and_position, single_file};
 
     #[test]
     fn test_resolve_parent_module() {
@@ -84,7 +78,7 @@ fn test_resolve_parent_module() {
             ",
         );
         let nav = analysis.parent_module(pos).unwrap().pop().unwrap();
-        nav.assert_match("foo MODULE FileId(1) 0..8");
+        nav.assert_match("foo MODULE FileId(0) 0..8");
     }
 
     #[test]
@@ -103,7 +97,7 @@ fn test_resolve_parent_module_on_module_decl() {
             ",
         );
         let nav = analysis.parent_module(pos).unwrap().pop().unwrap();
-        nav.assert_match("foo MODULE FileId(1) 0..8");
+        nav.assert_match("foo MODULE FileId(0) 0..8");
     }
 
     #[test]
@@ -119,37 +113,19 @@ mod baz { <|> }
             ",
         );
         let nav = analysis.parent_module(pos).unwrap().pop().unwrap();
-        nav.assert_match("baz MODULE FileId(1) 32..44");
+        nav.assert_match("baz MODULE FileId(0) 32..44");
     }
 
     #[test]
     fn test_resolve_crate_root() {
-        let mock = MockAnalysis::with_files(
+        let (analysis, file_id) = single_file(
             r#"
-//- /bar.rs
+//- /main.rs
 mod foo;
 //- /foo.rs
-// empty
+<|>
 "#,
         );
-        let root_file = mock.id_of("/bar.rs");
-        let mod_file = mock.id_of("/foo.rs");
-        let mut host = mock.analysis_host();
-        assert!(host.analysis().crate_for(mod_file).unwrap().is_empty());
-
-        let mut crate_graph = CrateGraph::default();
-        let crate_id = crate_graph.add_crate_root(
-            root_file,
-            Edition2018,
-            None,
-            CfgOptions::default(),
-            Env::default(),
-            Default::default(),
-        );
-        let mut change = Change::new();
-        change.set_crate_graph(crate_graph);
-        host.apply_change(change);
-
-        assert_eq!(host.analysis().crate_for(mod_file).unwrap(), vec![crate_id]);
+        assert_eq!(analysis.crate_for(file_id).unwrap().len(), 1);
     }
 }
diff --git a/crates/ide/src/references.rs b/crates/ide/src/references.rs
index 1e3e944e941..157e0dc949b 100644
--- a/crates/ide/src/references.rs
+++ b/crates/ide/src/references.rs
@@ -190,10 +190,11 @@ fn get_struct_def_name_for_struct_literal_search(
 
 #[cfg(test)]
 mod tests {
+    use base_db::FileId;
     use expect_test::{expect, Expect};
     use stdx::format_to;
 
-    use crate::{mock_analysis::MockAnalysis, SearchScope};
+    use crate::{mock_analysis::analysis_and_position, SearchScope};
 
     #[test]
     fn test_struct_literal_after_space() {
@@ -211,9 +212,9 @@ fn main() {
 }
 "#,
             expect![[r#"
-                Foo STRUCT FileId(1) 0..26 7..10 Other
+                Foo STRUCT FileId(0) 0..26 7..10 Other
 
-                FileId(1) 101..104 StructLiteral
+                FileId(0) 101..104 StructLiteral
             "#]],
         );
     }
@@ -229,10 +230,10 @@ fn main() {
 }
 "#,
             expect![[r#"
-                Foo STRUCT FileId(1) 0..13 7..10 Other
+                Foo STRUCT FileId(0) 0..13 7..10 Other
 
-                FileId(1) 41..44 Other
-                FileId(1) 54..57 StructLiteral
+                FileId(0) 41..44 Other
+                FileId(0) 54..57 StructLiteral
             "#]],
         );
     }
@@ -248,9 +249,9 @@ fn main() {
 }
 "#,
             expect![[r#"
-                Foo STRUCT FileId(1) 0..16 7..10 Other
+                Foo STRUCT FileId(0) 0..16 7..10 Other
 
-                FileId(1) 64..67 StructLiteral
+                FileId(0) 64..67 StructLiteral
             "#]],
         );
     }
@@ -267,9 +268,9 @@ fn main() {
 }
 "#,
             expect![[r#"
-                Foo STRUCT FileId(1) 0..16 7..10 Other
+                Foo STRUCT FileId(0) 0..16 7..10 Other
 
-                FileId(1) 54..57 StructLiteral
+                FileId(0) 54..57 StructLiteral
             "#]],
         );
     }
@@ -290,12 +291,12 @@ fn main() {
     i = 5;
 }"#,
             expect![[r#"
-                i IDENT_PAT FileId(1) 24..25 Other Write
+                i IDENT_PAT FileId(0) 24..25 Other Write
 
-                FileId(1) 50..51 Other Write
-                FileId(1) 54..55 Other Read
-                FileId(1) 76..77 Other Write
-                FileId(1) 94..95 Other Write
+                FileId(0) 50..51 Other Write
+                FileId(0) 54..55 Other Read
+                FileId(0) 76..77 Other Write
+                FileId(0) 94..95 Other Write
             "#]],
         );
     }
@@ -314,10 +315,10 @@ fn bar() {
 }
 "#,
             expect![[r#"
-                spam IDENT_PAT FileId(1) 19..23 Other
+                spam IDENT_PAT FileId(0) 19..23 Other
 
-                FileId(1) 34..38 Other Read
-                FileId(1) 41..45 Other Read
+                FileId(0) 34..38 Other Read
+                FileId(0) 41..45 Other Read
             "#]],
         );
     }
@@ -329,9 +330,9 @@ fn test_find_all_refs_for_param_inside() {
 fn foo(i : u32) -> u32 { i<|> }
 "#,
             expect![[r#"
-                i IDENT_PAT FileId(1) 7..8 Other
+                i IDENT_PAT FileId(0) 7..8 Other
 
-                FileId(1) 25..26 Other Read
+                FileId(0) 25..26 Other Read
             "#]],
         );
     }
@@ -343,9 +344,9 @@ fn test_find_all_refs_for_fn_param() {
 fn foo(i<|> : u32) -> u32 { i }
 "#,
             expect![[r#"
-                i IDENT_PAT FileId(1) 7..8 Other
+                i IDENT_PAT FileId(0) 7..8 Other
 
-                FileId(1) 25..26 Other Read
+                FileId(0) 25..26 Other Read
             "#]],
         );
     }
@@ -364,9 +365,9 @@ fn main(s: Foo) {
 }
 "#,
             expect![[r#"
-                spam RECORD_FIELD FileId(1) 17..30 21..25 Other
+                spam RECORD_FIELD FileId(0) 17..30 21..25 Other
 
-                FileId(1) 67..71 Other Read
+                FileId(0) 67..71 Other Read
             "#]],
         );
     }
@@ -381,7 +382,7 @@ fn f<|>(&self) {  }
 }
 "#,
             expect![[r#"
-                f FN FileId(1) 27..43 30..31 Other
+                f FN FileId(0) 27..43 30..31 Other
 
             "#]],
         );
@@ -398,7 +399,7 @@ enum Foo {
 }
 "#,
             expect![[r#"
-                B VARIANT FileId(1) 22..23 22..23 Other
+                B VARIANT FileId(0) 22..23 22..23 Other
 
             "#]],
         );
@@ -439,10 +440,10 @@ fn f() {
 }
 "#,
             expect![[r#"
-                Foo STRUCT FileId(2) 17..51 28..31 Other
+                Foo STRUCT FileId(1) 17..51 28..31 Other
 
-                FileId(1) 53..56 StructLiteral
-                FileId(3) 79..82 StructLiteral
+                FileId(0) 53..56 StructLiteral
+                FileId(2) 79..82 StructLiteral
             "#]],
         );
     }
@@ -469,9 +470,9 @@ pub struct Foo {
 }
 "#,
             expect![[r#"
-                foo SOURCE_FILE FileId(2) 0..35 Other
+                foo SOURCE_FILE FileId(1) 0..35 Other
 
-                FileId(1) 14..17 Other
+                FileId(0) 14..17 Other
             "#]],
         );
     }
@@ -497,10 +498,10 @@ pub(super) struct Foo<|> {
 }
 "#,
             expect![[r#"
-                Foo STRUCT FileId(3) 0..41 18..21 Other
+                Foo STRUCT FileId(2) 0..41 18..21 Other
 
-                FileId(2) 20..23 Other
-                FileId(2) 47..50 StructLiteral
+                FileId(1) 20..23 Other
+                FileId(1) 47..50 StructLiteral
             "#]],
         );
     }
@@ -525,20 +526,20 @@ pub fn quux<|>() {}
             code,
             None,
             expect![[r#"
-                quux FN FileId(1) 19..35 26..30 Other
+                quux FN FileId(0) 19..35 26..30 Other
 
+                FileId(1) 16..20 StructLiteral
                 FileId(2) 16..20 StructLiteral
-                FileId(3) 16..20 StructLiteral
             "#]],
         );
 
         check_with_scope(
             code,
-            Some("/bar.rs"),
+            Some(SearchScope::single_file(FileId(2))),
             expect![[r#"
-                quux FN FileId(1) 19..35 26..30 Other
+                quux FN FileId(0) 19..35 26..30 Other
 
-                FileId(3) 16..20 StructLiteral
+                FileId(2) 16..20 StructLiteral
             "#]],
         );
     }
@@ -556,10 +557,10 @@ fn foo() {
 }
 "#,
             expect![[r#"
-                m1 MACRO_CALL FileId(1) 0..46 29..31 Other
+                m1 MACRO_CALL FileId(0) 0..46 29..31 Other
 
-                FileId(1) 63..65 StructLiteral
-                FileId(1) 73..75 StructLiteral
+                FileId(0) 63..65 StructLiteral
+                FileId(0) 73..75 StructLiteral
             "#]],
         );
     }
@@ -574,10 +575,10 @@ fn foo() {
 }
 "#,
             expect![[r#"
-                i IDENT_PAT FileId(1) 23..24 Other Write
+                i IDENT_PAT FileId(0) 23..24 Other Write
 
-                FileId(1) 34..35 Other Write
-                FileId(1) 38..39 Other Read
+                FileId(0) 34..35 Other Write
+                FileId(0) 38..39 Other Read
             "#]],
         );
     }
@@ -596,10 +597,10 @@ fn foo() {
 }
 "#,
             expect![[r#"
-                f RECORD_FIELD FileId(1) 15..21 15..16 Other
+                f RECORD_FIELD FileId(0) 15..21 15..16 Other
 
-                FileId(1) 55..56 Other Read
-                FileId(1) 68..69 Other Write
+                FileId(0) 55..56 Other Read
+                FileId(0) 68..69 Other Write
             "#]],
         );
     }
@@ -614,9 +615,9 @@ fn foo() {
 }
 "#,
             expect![[r#"
-                i IDENT_PAT FileId(1) 19..20 Other
+                i IDENT_PAT FileId(0) 19..20 Other
 
-                FileId(1) 26..27 Other Write
+                FileId(0) 26..27 Other Write
             "#]],
         );
     }
@@ -638,9 +639,9 @@ fn main() {
 }
 "#,
             expect![[r#"
-                new FN FileId(1) 54..81 61..64 Other
+                new FN FileId(0) 54..81 61..64 Other
 
-                FileId(1) 126..129 StructLiteral
+                FileId(0) 126..129 StructLiteral
             "#]],
         );
     }
@@ -660,10 +661,10 @@ fn f<|>() {}
 fn g() { f(); }
 "#,
             expect![[r#"
-                f FN FileId(1) 22..31 25..26 Other
+                f FN FileId(0) 22..31 25..26 Other
 
-                FileId(2) 11..12 Other
-                FileId(2) 24..25 StructLiteral
+                FileId(1) 11..12 Other
+                FileId(1) 24..25 StructLiteral
             "#]],
         );
     }
@@ -672,11 +673,8 @@ fn check(ra_fixture: &str, expect: Expect) {
         check_with_scope(ra_fixture, None, expect)
     }
 
-    fn check_with_scope(ra_fixture: &str, search_scope: Option<&str>, expect: Expect) {
-        let (mock_analysis, pos) = MockAnalysis::with_files_and_position(ra_fixture);
-        let search_scope =
-            search_scope.map(|path| SearchScope::single_file(mock_analysis.id_of(path)));
-        let analysis = mock_analysis.analysis();
+    fn check_with_scope(ra_fixture: &str, search_scope: Option<SearchScope>, expect: Expect) {
+        let (analysis, pos) = analysis_and_position(ra_fixture);
         let refs = analysis.find_all_refs(pos, search_scope).unwrap().unwrap();
 
         let mut actual = String::new();
diff --git a/crates/ide/src/references/rename.rs b/crates/ide/src/references/rename.rs
index 3016297633b..36652707042 100644
--- a/crates/ide/src/references/rename.rs
+++ b/crates/ide/src/references/rename.rs
@@ -602,7 +602,7 @@ fn test_rename_mod() {
                         source_file_edits: [
                             SourceFileEdit {
                                 file_id: FileId(
-                                    2,
+                                    1,
                                 ),
                                 edit: TextEdit {
                                     indels: [
@@ -617,10 +617,10 @@ fn test_rename_mod() {
                         file_system_edits: [
                             MoveFile {
                                 src: FileId(
-                                    3,
+                                    2,
                                 ),
                                 anchor: FileId(
-                                    3,
+                                    2,
                                 ),
                                 dst: "foo2.rs",
                             },
@@ -655,7 +655,7 @@ fn main() {}
                         source_file_edits: [
                             SourceFileEdit {
                                 file_id: FileId(
-                                    1,
+                                    0,
                                 ),
                                 edit: TextEdit {
                                     indels: [
@@ -668,7 +668,7 @@ fn main() {}
                             },
                             SourceFileEdit {
                                 file_id: FileId(
-                                    3,
+                                    2,
                                 ),
                                 edit: TextEdit {
                                     indels: [
@@ -683,10 +683,10 @@ fn main() {}
                         file_system_edits: [
                             MoveFile {
                                 src: FileId(
-                                    2,
+                                    1,
                                 ),
                                 anchor: FileId(
-                                    2,
+                                    1,
                                 ),
                                 dst: "quux.rs",
                             },
@@ -715,7 +715,7 @@ fn test_rename_mod_in_dir() {
                         source_file_edits: [
                             SourceFileEdit {
                                 file_id: FileId(
-                                    1,
+                                    0,
                                 ),
                                 edit: TextEdit {
                                     indels: [
@@ -730,10 +730,10 @@ fn test_rename_mod_in_dir() {
                         file_system_edits: [
                             MoveFile {
                                 src: FileId(
-                                    2,
+                                    1,
                                 ),
                                 anchor: FileId(
-                                    2,
+                                    1,
                                 ),
                                 dst: "../foo2/mod.rs",
                             },
@@ -763,7 +763,7 @@ fn test_rename_unusually_nested_mod() {
                         source_file_edits: [
                             SourceFileEdit {
                                 file_id: FileId(
-                                    1,
+                                    0,
                                 ),
                                 edit: TextEdit {
                                     indels: [
@@ -778,10 +778,10 @@ fn test_rename_unusually_nested_mod() {
                         file_system_edits: [
                             MoveFile {
                                 src: FileId(
-                                    2,
+                                    1,
                                 ),
                                 anchor: FileId(
-                                    2,
+                                    1,
                                 ),
                                 dst: "bar.rs",
                             },
@@ -834,7 +834,7 @@ fn f() {
                         source_file_edits: [
                             SourceFileEdit {
                                 file_id: FileId(
-                                    2,
+                                    1,
                                 ),
                                 edit: TextEdit {
                                     indels: [
@@ -847,7 +847,7 @@ fn f() {
                             },
                             SourceFileEdit {
                                 file_id: FileId(
-                                    1,
+                                    0,
                                 ),
                                 edit: TextEdit {
                                     indels: [
@@ -862,10 +862,10 @@ fn f() {
                         file_system_edits: [
                             MoveFile {
                                 src: FileId(
-                                    3,
+                                    2,
                                 ),
                                 anchor: FileId(
-                                    3,
+                                    2,
                                 ),
                                 dst: "foo2.rs",
                             },
diff --git a/crates/ide/src/runnables.rs b/crates/ide/src/runnables.rs
index cfeff40c1a2..961066277fb 100644
--- a/crates/ide/src/runnables.rs
+++ b/crates/ide/src/runnables.rs
@@ -335,7 +335,7 @@ fn bench() {}
                     Runnable {
                         nav: NavigationTarget {
                             file_id: FileId(
-                                1,
+                                0,
                             ),
                             full_range: 1..13,
                             focus_range: Some(
@@ -353,7 +353,7 @@ fn bench() {}
                     Runnable {
                         nav: NavigationTarget {
                             file_id: FileId(
-                                1,
+                                0,
                             ),
                             full_range: 15..39,
                             focus_range: Some(
@@ -378,7 +378,7 @@ fn bench() {}
                     Runnable {
                         nav: NavigationTarget {
                             file_id: FileId(
-                                1,
+                                0,
                             ),
                             full_range: 41..75,
                             focus_range: Some(
@@ -403,7 +403,7 @@ fn bench() {}
                     Runnable {
                         nav: NavigationTarget {
                             file_id: FileId(
-                                1,
+                                0,
                             ),
                             full_range: 77..99,
                             focus_range: Some(
@@ -494,7 +494,7 @@ fn should_have_no_runnable_6() {}
                     Runnable {
                         nav: NavigationTarget {
                             file_id: FileId(
-                                1,
+                                0,
                             ),
                             full_range: 1..13,
                             focus_range: Some(
@@ -512,7 +512,7 @@ fn should_have_no_runnable_6() {}
                     Runnable {
                         nav: NavigationTarget {
                             file_id: FileId(
-                                1,
+                                0,
                             ),
                             full_range: 15..74,
                             focus_range: None,
@@ -532,7 +532,7 @@ fn should_have_no_runnable_6() {}
                     Runnable {
                         nav: NavigationTarget {
                             file_id: FileId(
-                                1,
+                                0,
                             ),
                             full_range: 76..148,
                             focus_range: None,
@@ -552,7 +552,7 @@ fn should_have_no_runnable_6() {}
                     Runnable {
                         nav: NavigationTarget {
                             file_id: FileId(
-                                1,
+                                0,
                             ),
                             full_range: 150..254,
                             focus_range: None,
@@ -596,7 +596,7 @@ fn foo() {}
                     Runnable {
                         nav: NavigationTarget {
                             file_id: FileId(
-                                1,
+                                0,
                             ),
                             full_range: 1..13,
                             focus_range: Some(
@@ -614,7 +614,7 @@ fn foo() {}
                     Runnable {
                         nav: NavigationTarget {
                             file_id: FileId(
-                                1,
+                                0,
                             ),
                             full_range: 44..98,
                             focus_range: None,
@@ -653,7 +653,7 @@ fn test_foo1() {}
                     Runnable {
                         nav: NavigationTarget {
                             file_id: FileId(
-                                1,
+                                0,
                             ),
                             full_range: 1..51,
                             focus_range: Some(
@@ -673,7 +673,7 @@ fn test_foo1() {}
                     Runnable {
                         nav: NavigationTarget {
                             file_id: FileId(
-                                1,
+                                0,
                             ),
                             full_range: 20..49,
                             focus_range: Some(
@@ -733,7 +733,7 @@ mod nested_tests_4 {}
                     Runnable {
                         nav: NavigationTarget {
                             file_id: FileId(
-                                1,
+                                0,
                             ),
                             full_range: 22..323,
                             focus_range: Some(
@@ -753,7 +753,7 @@ mod nested_tests_4 {}
                     Runnable {
                         nav: NavigationTarget {
                             file_id: FileId(
-                                1,
+                                0,
                             ),
                             full_range: 51..192,
                             focus_range: Some(
@@ -773,7 +773,7 @@ mod nested_tests_4 {}
                     Runnable {
                         nav: NavigationTarget {
                             file_id: FileId(
-                                1,
+                                0,
                             ),
                             full_range: 84..126,
                             focus_range: Some(
@@ -798,7 +798,7 @@ mod nested_tests_4 {}
                     Runnable {
                         nav: NavigationTarget {
                             file_id: FileId(
-                                1,
+                                0,
                             ),
                             full_range: 140..182,
                             focus_range: Some(
@@ -823,7 +823,7 @@ mod nested_tests_4 {}
                     Runnable {
                         nav: NavigationTarget {
                             file_id: FileId(
-                                1,
+                                0,
                             ),
                             full_range: 202..286,
                             focus_range: Some(
@@ -843,7 +843,7 @@ mod nested_tests_4 {}
                     Runnable {
                         nav: NavigationTarget {
                             file_id: FileId(
-                                1,
+                                0,
                             ),
                             full_range: 235..276,
                             focus_range: Some(
@@ -886,7 +886,7 @@ fn test_foo1() {}
                     Runnable {
                         nav: NavigationTarget {
                             file_id: FileId(
-                                1,
+                                0,
                             ),
                             full_range: 1..50,
                             focus_range: Some(
@@ -934,7 +934,7 @@ fn test_foo1() {}
                     Runnable {
                         nav: NavigationTarget {
                             file_id: FileId(
-                                1,
+                                0,
                             ),
                             full_range: 1..72,
                             focus_range: Some(
diff --git a/crates/ide/src/syntax_highlighting/tests.rs b/crates/ide/src/syntax_highlighting/tests.rs
index 211e62ea1fc..eaa4e163ea2 100644
--- a/crates/ide/src/syntax_highlighting/tests.rs
+++ b/crates/ide/src/syntax_highlighting/tests.rs
@@ -462,12 +462,12 @@ macro_rules! noop {
 fn test_extern_crate() {
     check_highlighting(
         r#"
-        //- /main.rs
+        //- /main.rs crate:main deps:std,alloc
         extern crate std;
         extern crate alloc as abc;
-        //- /std/lib.rs
+        //- /std/lib.rs crate:std
         pub struct S;
-        //- /alloc/lib.rs
+        //- /alloc/lib.rs crate:alloc
         pub struct A
         "#,
         expect_file!["./test_data/highlight_extern_crate.html"],