5 files changed, 129 insertions, 62 deletions

diff --git a/crates/ide/src/hover.rs b/crates/ide/src/hover.rs
index 592610eab..01dd0c0da 100644
--- a/crates/ide/src/hover.rs
+++ b/crates/ide/src/hover.rs
@@ -3016,8 +3016,8 @@ fn foo() {
                                     file_id: FileId(
                                         1,
                                     ),
-                                    full_range: 246..428,
-                                    focus_range: 285..291,
+                                    full_range: 247..429,
+                                    focus_range: 286..292,
                                     name: "Future",
                                     kind: Trait,
                                     description: "pub trait Future",
diff --git a/crates/ide_assists/src/handlers/convert_into_to_from.rs b/crates/ide_assists/src/handlers/convert_into_to_from.rs
index 199e1ad5c..79a0c4879 100644
--- a/crates/ide_assists/src/handlers/convert_into_to_from.rs
+++ b/crates/ide_assists/src/handlers/convert_into_to_from.rs
@@ -6,6 +6,8 @@ use syntax::ast::{self, AstNode, NameOwner};
 
 use crate::{AssistContext, AssistId, AssistKind, Assists};
 
+// FIXME: this should be a diagnostic
+
 // Assist: convert_into_to_from
 //
 // Converts an Into impl to an equivalent From impl.
@@ -114,12 +116,14 @@ pub(crate) fn convert_into_to_from(acc: &mut Assists, ctx: &AssistContext) -> Op
 mod tests {
     use super::*;
 
-    use crate::tests::check_assist;
+    use crate::tests::{check_assist, check_assist_not_applicable};
 
     #[test]
     fn convert_into_to_from_converts_a_struct() {
-        check_convert_into_to_from(
+        check_assist(
+            convert_into_to_from,
             r#"
+//- minicore: from
 struct Thing {
     a: String,
     b: usize
@@ -154,8 +158,10 @@ impl From<usize> for Thing {
 
     #[test]
     fn convert_into_to_from_converts_enums() {
-        check_convert_into_to_from(
+        check_assist(
+            convert_into_to_from,
             r#"
+//- minicore: from
 enum Thing {
     Foo(String),
     Bar(String)
@@ -190,8 +196,10 @@ impl From<Thing> for String {
 
     #[test]
     fn convert_into_to_from_on_enum_with_lifetimes() {
-        check_convert_into_to_from(
+        check_assist(
+            convert_into_to_from,
             r#"
+//- minicore: from
 enum Thing<'a> {
     Foo(&'a str),
     Bar(&'a str)
@@ -226,8 +234,10 @@ impl<'a> From<Thing<'a>> for &'a str {
 
     #[test]
     fn convert_into_to_from_works_on_references() {
-        check_convert_into_to_from(
+        check_assist(
+            convert_into_to_from,
             r#"
+//- minicore: from
 struct Thing(String);
 
 impl $0core::convert::Into<String> for &Thing {
@@ -250,8 +260,10 @@ impl From<&Thing> for String {
 
     #[test]
     fn convert_into_to_from_works_on_qualified_structs() {
-        check_convert_into_to_from(
+        check_assist(
+            convert_into_to_from,
             r#"
+//- minicore: from
 mod things {
     pub struct Thing(String);
     pub struct BetterThing(String);
@@ -280,8 +292,10 @@ impl From<&things::Thing> for things::BetterThing {
 
     #[test]
     fn convert_into_to_from_works_on_qualified_enums() {
-        check_convert_into_to_from(
+        check_assist(
+            convert_into_to_from,
             r#"
+//- minicore: from
 mod things {
     pub enum Thing {
         A(String)
@@ -323,10 +337,12 @@ impl From<&things::Thing> for things::BetterThing {
     #[test]
     fn convert_into_to_from_not_applicable_on_any_trait_named_into() {
         check_assist_not_applicable(
+            convert_into_to_from,
             r#"
-pub trait Into<T> {{
+//- minicore: from
+pub trait Into<T> {
     pub fn into(self) -> T;
-}}
+}
 
 struct Thing {
     a: String,
@@ -342,14 +358,4 @@ impl $0Into<Thing> for String {
 "#,
         );
     }
-
-    fn check_convert_into_to_from(before: &str, after: &str) {
-        let before = &format!("//- /main.rs crate:main deps:core{}{}", before, FamousDefs::FIXTURE);
-        check_assist(convert_into_to_from, before, after);
-    }
-
-    fn check_assist_not_applicable(before: &str) {
-        let before = &format!("//- /main.rs crate:main deps:core{}{}", before, FamousDefs::FIXTURE);
-        crate::tests::check_assist_not_applicable(convert_into_to_from, before);
-    }
 }
diff --git a/crates/ide_assists/src/handlers/generate_from_impl_for_enum.rs b/crates/ide_assists/src/handlers/generate_from_impl_for_enum.rs
index ce6998d82..8727be07d 100644
--- a/crates/ide_assists/src/handlers/generate_from_impl_for_enum.rs
+++ b/crates/ide_assists/src/handlers/generate_from_impl_for_enum.rs
@@ -110,14 +110,19 @@ mod tests {
     fn test_generate_from_impl_for_enum() {
         check_assist(
             generate_from_impl_for_enum,
-            "enum A { $0One(u32) }",
-            r#"enum A { One(u32) }
+            r#"
+//- minicore: from
+enum A { $0One(u32) }
+"#,
+            r#"
+enum A { One(u32) }
 
 impl From<u32> for A {
     fn from(v: u32) -> Self {
         Self::One(v)
     }
-}"#,
+}
+"#,
         );
     }
 
@@ -125,53 +130,71 @@ impl From<u32> for A {
     fn test_generate_from_impl_for_enum_complicated_path() {
         check_assist(
             generate_from_impl_for_enum,
-            r#"enum A { $0One(foo::bar::baz::Boo) }"#,
-            r#"enum A { One(foo::bar::baz::Boo) }
+            r#"
+//- minicore: from
+enum A { $0One(foo::bar::baz::Boo) }
+"#,
+            r#"
+enum A { One(foo::bar::baz::Boo) }
 
 impl From<foo::bar::baz::Boo> for A {
     fn from(v: foo::bar::baz::Boo) -> Self {
         Self::One(v)
     }
-}"#,
+}
+"#,
         );
     }
 
-    fn check_not_applicable(ra_fixture: &str) {
-        let fixture =
-            format!("//- /main.rs crate:main deps:core\n{}\n{}", ra_fixture, FamousDefs::FIXTURE);
-        check_assist_not_applicable(generate_from_impl_for_enum, &fixture)
-    }
-
     #[test]
     fn test_add_from_impl_no_element() {
-        check_not_applicable("enum A { $0One }");
+        check_assist_not_applicable(
+            generate_from_impl_for_enum,
+            r#"
+//- minicore: from
+enum A { $0One }
+"#,
+        );
     }
 
     #[test]
     fn test_add_from_impl_more_than_one_element_in_tuple() {
-        check_not_applicable("enum A { $0One(u32, String) }");
+        check_assist_not_applicable(
+            generate_from_impl_for_enum,
+            r#"
+//- minicore: from
+enum A { $0One(u32, String) }
+"#,
+        );
     }
 
     #[test]
     fn test_add_from_impl_struct_variant() {
         check_assist(
             generate_from_impl_for_enum,
-            "enum A { $0One { x: u32 } }",
-            r#"enum A { One { x: u32 } }
+            r#"
+//- minicore: from
+enum A { $0One { x: u32 } }
+"#,
+            r#"
+enum A { One { x: u32 } }
 
 impl From<u32> for A {
     fn from(x: u32) -> Self {
         Self::One { x }
     }
-}"#,
+}
+"#,
         );
     }
 
     #[test]
     fn test_add_from_impl_already_exists() {
         cov_mark::check!(test_add_from_impl_already_exists);
-        check_not_applicable(
+        check_assist_not_applicable(
+            generate_from_impl_for_enum,
             r#"
+//- minicore: from
 enum A { $0One(u32), }
 
 impl From<u32> for A {
@@ -187,7 +210,9 @@ impl From<u32> for A {
     fn test_add_from_impl_different_variant_impl_exists() {
         check_assist(
             generate_from_impl_for_enum,
-            r#"enum A { $0One(u32), Two(String), }
+            r#"
+//- minicore: from
+enum A { $0One(u32), Two(String), }
 
 impl From<String> for A {
     fn from(v: String) -> Self {
@@ -197,8 +222,10 @@ impl From<String> for A {
 
 pub trait From<T> {
     fn from(T) -> Self;
-}"#,
-            r#"enum A { One(u32), Two(String), }
+}
+"#,
+            r#"
+enum A { One(u32), Two(String), }
 
 impl From<u32> for A {
     fn from(v: u32) -> Self {
@@ -214,7 +241,8 @@ impl From<String> for A {
 
 pub trait From<T> {
     fn from(T) -> Self;
-}"#,
+}
+"#,
         );
     }
 
@@ -222,14 +250,19 @@ pub trait From<T> {
     fn test_add_from_impl_static_str() {
         check_assist(
             generate_from_impl_for_enum,
-            "enum A { $0One(&'static str) }",
-            r#"enum A { One(&'static str) }
+            r#"
+//- minicore: from
+enum A { $0One(&'static str) }
+"#,
+            r#"
+enum A { One(&'static str) }
 
 impl From<&'static str> for A {
     fn from(v: &'static str) -> Self {
         Self::One(v)
     }
-}"#,
+}
+"#,
         );
     }
 
@@ -237,14 +270,19 @@ impl From<&'static str> for A {
     fn test_add_from_impl_generic_enum() {
         check_assist(
             generate_from_impl_for_enum,
-            "enum Generic<T, U: Clone> { $0One(T), Two(U) }",
-            r#"enum Generic<T, U: Clone> { One(T), Two(U) }
+            r#"
+//- minicore: from
+enum Generic<T, U: Clone> { $0One(T), Two(U) }
+"#,
+            r#"
+enum Generic<T, U: Clone> { One(T), Two(U) }
 
 impl<T, U: Clone> From<T> for Generic<T, U> {
     fn from(v: T) -> Self {
         Self::One(v)
     }
-}"#,
+}
+"#,
         );
     }
 
@@ -252,14 +290,19 @@ impl<T, U: Clone> From<T> for Generic<T, U> {
     fn test_add_from_impl_with_lifetime() {
         check_assist(
             generate_from_impl_for_enum,
-            "enum Generic<'a> { $0One(&'a i32) }",
-            r#"enum Generic<'a> { One(&'a i32) }
+            r#"
+//- minicore: from
+enum Generic<'a> { $0One(&'a i32) }
+"#,
+            r#"
+enum Generic<'a> { One(&'a i32) }
 
 impl<'a> From<&'a i32> for Generic<'a> {
     fn from(v: &'a i32) -> Self {
         Self::One(v)
     }
-}"#,
+}
+"#,
         );
     }
 }
diff --git a/crates/ide_db/src/helpers/famous_defs_fixture.rs b/crates/ide_db/src/helpers/famous_defs_fixture.rs
index d26b7162e..fa4fc5307 100644
--- a/crates/ide_db/src/helpers/famous_defs_fixture.rs
+++ b/crates/ide_db/src/helpers/famous_defs_fixture.rs
@@ -10,16 +10,6 @@ pub mod cmp {
     }
 }
 
-pub mod convert {
-    pub trait From<T> {
-        fn from(t: T) -> Self;
-    }
-
-    pub trait Into<T> {
-        pub fn into(self) -> T;
-    }
-}
-
 pub mod prelude {
     pub mod rust_2018 {
         pub use crate::{
diff --git a/crates/test_utils/src/minicore.rs b/crates/test_utils/src/minicore.rs
index 4093a04bc..a5a7c2f7d 100644
--- a/crates/test_utils/src/minicore.rs
+++ b/crates/test_utils/src/minicore.rs
@@ -23,6 +23,7 @@
 //!     iterator: option
 //!     iterators: iterator
 //!     default: sized
+//!     from: sized
 
 pub mod marker {
     // region:sized
@@ -46,6 +47,32 @@ pub mod default {
 }
 // endregion:default
 
+// region:from
+pub mod convert {
+    pub trait From<T>: Sized {
+        fn from(_: T) -> Self;
+    }
+    pub trait Into<T>: Sized {
+        fn into(self) -> T;
+    }
+
+    impl<T, U> Into<U> for T
+    where
+        U: From<T>,
+    {
+        fn into(self) -> U {
+            U::from(self)
+        }
+    }
+
+    impl<T> From<T> for T {
+        fn from(t: T) -> T {
+            t
+        }
+    }
+}
+// endregion:from
+
 pub mod ops {
     // region:coerce_unsized
     mod unsize {
@@ -324,6 +351,7 @@ pub mod prelude {
             ops::{Fn, FnMut, FnOnce},           // :fn
             option::Option::{self, None, Some}, // :option
             result::Result::{self, Err, Ok},    // :result
+            convert::{From, Into},    // :from
         };
     }