2 files changed, 9 insertions, 61 deletions

diff --git a/crates/ide_db/src/helpers.rs b/crates/ide_db/src/helpers.rs
index 00900cdc2..d96028cbc 100644
--- a/crates/ide_db/src/helpers.rs
+++ b/crates/ide_db/src/helpers.rs
@@ -74,12 +74,19 @@ pub fn visit_file_defs(
 /// somewhat similar to the known paths infra inside hir, but it different; We
 /// want to make sure that IDE specific paths don't become interesting inside
 /// the compiler itself as well.
+///
+/// Note that, by default, rust-analyzer tests **do not** include core or std
+/// libraries. If you are writing tests for functionality using [`FamousDefs`],
+/// you'd want to include [minicore](test_utils::MiniCore) declaration at the
+/// start of your tests:
+///
+/// ```
+/// //- minicore: iterator, ord, derive
+/// ```
 pub struct FamousDefs<'a, 'b>(pub &'a Semantics<'b, RootDatabase>, pub Option<Crate>);
 
 #[allow(non_snake_case)]
 impl FamousDefs<'_, '_> {
-    pub const FIXTURE: &'static str = include_str!("helpers/famous_defs_fixture.rs");
-
     pub fn std(&self) -> Option<Crate> {
         self.find_crate("std")
     }
diff --git a/crates/ide_db/src/helpers/famous_defs_fixture.rs b/crates/ide_db/src/helpers/famous_defs_fixture.rs
deleted file mode 100644
index 551203936..000000000
--- a/crates/ide_db/src/helpers/famous_defs_fixture.rs
+++ /dev/null
@@ -1,59 +0,0 @@
-//- /libcore.rs crate:core
-//! Signatures of traits, types and functions from the core lib for use in tests.
-pub mod cmp {
-
-    pub trait Ord {
-        fn cmp(&self, other: &Self) -> Ordering;
-        fn max(self, other: Self) -> Self;
-        fn min(self, other: Self) -> Self;
-        fn clamp(self, min: Self, max: Self) -> Self;
-    }
-}
-
-pub mod convert {
-    pub trait From<T> {
-        fn from(t: T) -> Self;
-    }
-
-    pub trait Into<T> {
-        pub fn into(self) -> T;
-    }
-}
-
-pub mod default {
-    pub trait Default {
-        fn default() -> Self;
-    }
-}
-
-pub mod option {
-    pub enum Option<T> {
-        None,
-        Some(T),
-    }
-}
-
-pub mod prelude {
-    pub mod rust_2018 {
-        pub use crate::{
-            cmp::Ord,
-            convert::{From, Into},
-            default::Default,
-            iter::{IntoIterator, Iterator},
-            ops::{Fn, FnMut, FnOnce},
-            option::Option::{self, *},
-        };
-    }
-}
-#[prelude_import]
-pub use prelude::rust_2018::*;
-//- /libstd.rs crate:std deps:core
-//! Signatures of traits, types and functions from the std lib for use in tests.
-
-/// Docs for return_keyword
-mod return_keyword {}
-
-/// Docs for prim_str
-mod prim_str {}
-
-pub use core::ops;