8 files changed, 166 insertions, 80 deletions

diff --git a/crates/assists/src/handlers/extract_assignment.rs b/crates/assists/src/handlers/pull_assignment_up.rs
index ae99598c0..560d93e10 100644
--- a/crates/assists/src/handlers/extract_assignment.rs
+++ b/crates/assists/src/handlers/pull_assignment_up.rs
@@ -9,9 +9,9 @@ use crate::{
     AssistId, AssistKind,
 };
 
-// Assist: extract_assignment
+// Assist: pull_assignment_up
 //
-// Extracts variable assigment to outside an if or match statement.
+// Extracts variable assignment to outside an if or match statement.
 //
 // ```
 // fn main() {
@@ -36,7 +36,7 @@ use crate::{
 //     };
 // }
 // ```
-pub(crate) fn extract_assigment(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+pub(crate) fn pull_assignment_up(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
     let assign_expr = ctx.find_node_at_offset::<ast::BinExpr>()?;
     let name_expr = if assign_expr.op_kind()? == ast::BinOp::Assignment {
         assign_expr.lhs()?
@@ -61,8 +61,8 @@ pub(crate) fn extract_assigment(acc: &mut Assists, ctx: &AssistContext) -> Optio
     let expr_stmt = make::expr_stmt(new_stmt);
 
     acc.add(
-        AssistId("extract_assignment", AssistKind::RefactorExtract),
-        "Extract assignment",
+        AssistId("pull_assignment_up", AssistKind::RefactorExtract),
+        "Pull assignment up",
         old_stmt.syntax().text_range(),
         move |edit| {
             edit.replace(old_stmt.syntax().text_range(), format!("{} = {};", name_expr, expr_stmt));
@@ -104,7 +104,7 @@ fn exprify_if(
             ast::ElseBranch::Block(exprify_block(block, sema, name)?)
         }
         ast::ElseBranch::IfExpr(expr) => {
-            mark::hit!(test_extract_assigment_chained_if);
+            mark::hit!(test_pull_assignment_up_chained_if);
             ast::ElseBranch::IfExpr(ast::IfExpr::cast(
                 exprify_if(&expr, sema, name)?.syntax().to_owned(),
             )?)
@@ -144,7 +144,7 @@ fn is_equivalent(
 ) -> bool {
     match (expr0, expr1) {
         (ast::Expr::FieldExpr(field_expr0), ast::Expr::FieldExpr(field_expr1)) => {
-            mark::hit!(test_extract_assignment_field_assignment);
+            mark::hit!(test_pull_assignment_up_field_assignment);
             sema.resolve_field(field_expr0) == sema.resolve_field(field_expr1)
         }
         (ast::Expr::PathExpr(path0), ast::Expr::PathExpr(path1)) => {
@@ -167,9 +167,9 @@ mod tests {
     use crate::tests::{check_assist, check_assist_not_applicable};
 
     #[test]
-    fn test_extract_assignment_if() {
+    fn test_pull_assignment_up_if() {
         check_assist(
-            extract_assigment,
+            pull_assignment_up,
             r#"
 fn foo() {
     let mut a = 1;
@@ -194,9 +194,9 @@ fn foo() {
     }
 
     #[test]
-    fn test_extract_assignment_match() {
+    fn test_pull_assignment_up_match() {
         check_assist(
-            extract_assigment,
+            pull_assignment_up,
             r#"
 fn foo() {
     let mut a = 1;
@@ -233,9 +233,9 @@ fn foo() {
     }
 
     #[test]
-    fn test_extract_assignment_not_last_not_applicable() {
+    fn test_pull_assignment_up_not_last_not_applicable() {
         check_assist_not_applicable(
-            extract_assigment,
+            pull_assignment_up,
             r#"
 fn foo() {
     let mut a = 1;
@@ -251,10 +251,10 @@ fn foo() {
     }
 
     #[test]
-    fn test_extract_assignment_chained_if() {
-        mark::check!(test_extract_assigment_chained_if);
+    fn test_pull_assignment_up_chained_if() {
+        mark::check!(test_pull_assignment_up_chained_if);
         check_assist(
-            extract_assigment,
+            pull_assignment_up,
             r#"
 fn foo() {
     let mut a = 1;
@@ -283,9 +283,9 @@ fn foo() {
     }
 
     #[test]
-    fn test_extract_assigment_retains_stmts() {
+    fn test_pull_assignment_up_retains_stmts() {
         check_assist(
-            extract_assigment,
+            pull_assignment_up,
             r#"
 fn foo() {
     let mut a = 1;
@@ -314,9 +314,9 @@ fn foo() {
     }
 
     #[test]
-    fn extract_assignment_let_stmt_not_applicable() {
+    fn pull_assignment_up_let_stmt_not_applicable() {
         check_assist_not_applicable(
-            extract_assigment,
+            pull_assignment_up,
             r#"
 fn foo() {
     let mut a = 1;
@@ -331,9 +331,9 @@ fn foo() {
     }
 
     #[test]
-    fn extract_assignment_if_missing_assigment_not_applicable() {
+    fn pull_assignment_up_if_missing_assigment_not_applicable() {
         check_assist_not_applicable(
-            extract_assigment,
+            pull_assignment_up,
             r#"
 fn foo() {
     let mut a = 1;
@@ -346,9 +346,9 @@ fn foo() {
     }
 
     #[test]
-    fn extract_assignment_match_missing_assigment_not_applicable() {
+    fn pull_assignment_up_match_missing_assigment_not_applicable() {
         check_assist_not_applicable(
-            extract_assigment,
+            pull_assignment_up,
             r#"
 fn foo() {
     let mut a = 1;
@@ -367,10 +367,10 @@ fn foo() {
     }
 
     #[test]
-    fn test_extract_assignment_field_assignment() {
-        mark::check!(test_extract_assignment_field_assignment);
+    fn test_pull_assignment_up_field_assignment() {
+        mark::check!(test_pull_assignment_up_field_assignment);
         check_assist(
-            extract_assigment,
+            pull_assignment_up,
             r#"
 struct A(usize);
 
diff --git a/crates/assists/src/lib.rs b/crates/assists/src/lib.rs
index 212464f85..01baa65fe 100644
--- a/crates/assists/src/lib.rs
+++ b/crates/assists/src/lib.rs
@@ -116,7 +116,6 @@ mod handlers {
     mod convert_integer_literal;
     mod early_return;
     mod expand_glob_import;
-    mod extract_assignment;
     mod extract_module_to_file;
     mod extract_struct_from_enum_variant;
     mod extract_variable;
@@ -125,8 +124,8 @@ mod handlers {
     mod flip_binexpr;
     mod flip_comma;
     mod flip_trait_bound;
-    mod generate_derive;
     mod generate_default_from_enum_variant;
+    mod generate_derive;
     mod generate_from_impl_for_enum;
     mod generate_function;
     mod generate_impl;
@@ -139,6 +138,7 @@ mod handlers {
     mod merge_match_arms;
     mod move_bounds;
     mod move_guard;
+    mod pull_assignment_up;
     mod qualify_path;
     mod raw_string;
     mod remove_dbg;
@@ -168,7 +168,6 @@ mod handlers {
             convert_integer_literal::convert_integer_literal,
             early_return::convert_to_guarded_return,
             expand_glob_import::expand_glob_import,
-            extract_assignment::extract_assigment,
             extract_module_to_file::extract_module_to_file,
             extract_struct_from_enum_variant::extract_struct_from_enum_variant,
             extract_variable::extract_variable,
@@ -177,8 +176,8 @@ mod handlers {
             flip_binexpr::flip_binexpr,
             flip_comma::flip_comma,
             flip_trait_bound::flip_trait_bound,
-            generate_derive::generate_derive,
             generate_default_from_enum_variant::generate_default_from_enum_variant,
+            generate_derive::generate_derive,
             generate_from_impl_for_enum::generate_from_impl_for_enum,
             generate_function::generate_function,
             generate_impl::generate_impl,
@@ -192,6 +191,7 @@ mod handlers {
             move_bounds::move_bounds_to_where_clause,
             move_guard::move_arm_cond_to_match_guard,
             move_guard::move_guard_to_arm_body,
+            pull_assignment_up::pull_assignment_up,
             qualify_path::qualify_path,
             raw_string::add_hash,
             raw_string::make_usual_string,
diff --git a/crates/assists/src/tests/generated.rs b/crates/assists/src/tests/generated.rs
index b91a816e8..85e3c6742 100644
--- a/crates/assists/src/tests/generated.rs
+++ b/crates/assists/src/tests/generated.rs
@@ -238,35 +238,6 @@ fn qux(bar: Bar, baz: Baz) {}
 }
 
 #[test]
-fn doctest_extract_assignment() {
-    check_doc_test(
-        "extract_assignment",
-        r#####"
-fn main() {
-    let mut foo = 6;
-
-    if true {
-        <|>foo = 5;
-    } else {
-        foo = 4;
-    }
-}
-"#####,
-        r#####"
-fn main() {
-    let mut foo = 6;
-
-    foo = if true {
-        5
-    } else {
-        4
-    };
-}
-"#####,
-    )
-}
-
-#[test]
 fn doctest_extract_module_to_file() {
     check_doc_test(
         "extract_module_to_file",
@@ -767,6 +738,35 @@ fn handle(action: Action) {
 }
 
 #[test]
+fn doctest_pull_assignment_up() {
+    check_doc_test(
+        "pull_assignment_up",
+        r#####"
+fn main() {
+    let mut foo = 6;
+
+    if true {
+        <|>foo = 5;
+    } else {
+        foo = 4;
+    }
+}
+"#####,
+        r#####"
+fn main() {
+    let mut foo = 6;
+
+    foo = if true {
+        5
+    } else {
+        4
+    };
+}
+"#####,
+    )
+}
+
+#[test]
 fn doctest_qualify_path() {
     check_doc_test(
         "qualify_path",
diff --git a/crates/hir/src/code_model.rs b/crates/hir/src/code_model.rs
index 62eccf475..a2255508e 100644
--- a/crates/hir/src/code_model.rs
+++ b/crates/hir/src/code_model.rs
@@ -5,9 +5,7 @@ use arrayvec::ArrayVec;
 use base_db::{CrateDisplayName, CrateId, Edition, FileId};
 use either::Either;
 use hir_def::{
-    adt::ReprKind,
-    adt::StructKind,
-    adt::VariantData,
+    adt::{ReprKind, StructKind, VariantData},
     builtin_type::BuiltinType,
     expr::{BindingAnnotation, LabelId, Pat, PatId},
     import_map,
@@ -31,7 +29,7 @@ use hir_expand::{
 };
 use hir_ty::{
     autoderef,
-    display::{HirDisplayError, HirFormatter},
+    display::{write_bounds_like_dyn_trait, HirDisplayError, HirFormatter},
     method_resolution,
     traits::{FnTrait, Solution, SolutionVariables},
     ApplicationTy, BoundVar, CallableDefId, Canonical, DebruijnIndex, FnSig, GenericPredicate,
@@ -1293,6 +1291,20 @@ impl TypeParam {
     }
 }
 
+impl HirDisplay for TypeParam {
+    fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
+        write!(f, "{}", self.name(f.db))?;
+        let bounds = f.db.generic_predicates_for_param(self.id);
+        let substs = Substs::type_params(f.db, self.id.parent);
+        let predicates = bounds.iter().cloned().map(|b| b.subst(&substs)).collect::<Vec<_>>();
+        if !(predicates.is_empty() || f.omit_verbose_types()) {
+            write!(f, ": ")?;
+            write_bounds_like_dyn_trait(&predicates, f)?;
+        }
+        Ok(())
+    }
+}
+
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
 pub struct LifetimeParam {
     pub(crate) id: LifetimeParamId,
diff --git a/crates/hir_ty/src/display.rs b/crates/hir_ty/src/display.rs
index 0e827a29e..a54225c18 100644
--- a/crates/hir_ty/src/display.rs
+++ b/crates/hir_ty/src/display.rs
@@ -595,7 +595,7 @@ impl HirDisplay for FnSig {
     }
 }
 
-fn write_bounds_like_dyn_trait(
+pub fn write_bounds_like_dyn_trait(
     predicates: &[GenericPredicate],
     f: &mut HirFormatter,
 ) -> Result<(), HirDisplayError> {
diff --git a/crates/ide/src/display/short_label.rs b/crates/ide/src/display/short_label.rs
index ea49d9f97..990f740b8 100644
--- a/crates/ide/src/display/short_label.rs
+++ b/crates/ide/src/display/short_label.rs
@@ -87,6 +87,17 @@ impl ShortLabel for ast::Variant {
     }
 }
 
+impl ShortLabel for ast::ConstParam {
+    fn short_label(&self) -> Option<String> {
+        let mut buf = "const ".to_owned();
+        buf.push_str(self.name()?.text().as_str());
+        if let Some(type_ref) = self.ty() {
+            format_to!(buf, ": {}", type_ref.syntax());
+        }
+        Some(buf)
+    }
+}
+
 fn short_label_from_ty<T>(node: &T, ty: Option<ast::Type>, prefix: &str) -> Option<String>
 where
     T: NameOwner + VisibilityOwner,
diff --git a/crates/ide/src/hover.rs b/crates/ide/src/hover.rs
index 2737c900f..c0786eb51 100644
--- a/crates/ide/src/hover.rs
+++ b/crates/ide/src/hover.rs
@@ -70,7 +70,7 @@ impl HoverConfig {
 #[derive(Debug, Clone)]
 pub enum HoverAction {
     Runnable(Runnable),
-    Implementaion(FilePosition),
+    Implementation(FilePosition),
     GoToType(Vec<HoverGotoTypeData>),
 }
 
@@ -116,12 +116,13 @@ pub(crate) fn hover(
     };
     if let Some(definition) = definition {
         if let Some(markup) = hover_for_definition(db, definition) {
+            let markup = markup.as_str();
             let markup = if !markdown {
-                remove_markdown(&markup.as_str())
+                remove_markdown(markup)
             } else if links_in_hover {
-                rewrite_links(db, &markup.as_str(), &definition)
+                rewrite_links(db, markup, &definition)
             } else {
-                remove_links(&markup.as_str())
+                remove_links(markup)
             };
             res.markup = Markup::from(markup);
             if let Some(action) = show_implementations_action(db, definition) {
@@ -175,7 +176,7 @@ pub(crate) fn hover(
 
 fn show_implementations_action(db: &RootDatabase, def: Definition) -> Option<HoverAction> {
     fn to_action(nav_target: NavigationTarget) -> HoverAction {
-        HoverAction::Implementaion(FilePosition {
+        HoverAction::Implementation(FilePosition {
             file_id: nav_target.file_id,
             offset: nav_target.focus_or_full_range().start(),
         })
@@ -370,10 +371,8 @@ fn hover_for_definition(db: &RootDatabase, def: Definition) -> Option<Markup> {
         }
         Definition::Label(it) => Some(Markup::fenced_block(&it.name(db))),
         Definition::LifetimeParam(it) => Some(Markup::fenced_block(&it.name(db))),
-        Definition::TypeParam(_) | Definition::ConstParam(_) => {
-            // FIXME: Hover for generic param
-            None
-        }
+        Definition::TypeParam(type_param) => Some(Markup::fenced_block(&type_param.display(db))),
+        Definition::ConstParam(it) => from_def_source(db, it, None),
     };
 
     fn from_def_source<A, D>(db: &RootDatabase, def: D, mod_path: Option<String>) -> Option<Markup>
@@ -1393,7 +1392,7 @@ fn bar() { fo<|>o(); }
             r"unsafe trait foo<|>() {}",
             expect![[r#"
                 [
-                    Implementaion(
+                    Implementation(
                         FilePosition {
                             file_id: FileId(
                                 0,
@@ -2105,7 +2104,7 @@ fn foo() { let bar = Bar; bar.fo<|>o(); }
             r#"trait foo<|>() {}"#,
             expect![[r#"
                 [
-                    Implementaion(
+                    Implementation(
                         FilePosition {
                             file_id: FileId(
                                 0,
@@ -2124,7 +2123,7 @@ fn foo() { let bar = Bar; bar.fo<|>o(); }
             r"struct foo<|>() {}",
             expect![[r#"
                 [
-                    Implementaion(
+                    Implementation(
                         FilePosition {
                             file_id: FileId(
                                 0,
@@ -2143,7 +2142,7 @@ fn foo() { let bar = Bar; bar.fo<|>o(); }
             r#"union foo<|>() {}"#,
             expect![[r#"
                 [
-                    Implementaion(
+                    Implementation(
                         FilePosition {
                             file_id: FileId(
                                 0,
@@ -2162,7 +2161,7 @@ fn foo() { let bar = Bar; bar.fo<|>o(); }
             r"enum foo<|>() { A, B }",
             expect![[r#"
                 [
-                    Implementaion(
+                    Implementation(
                         FilePosition {
                             file_id: FileId(
                                 0,
@@ -3257,4 +3256,68 @@ fn foo() {
             "#]],
         );
     }
+
+    #[test]
+    fn hover_type_param() {
+        check(
+            r#"
+struct Foo<T>(T);
+trait Copy {}
+trait Clone {}
+trait Sized {}
+impl<T: Copy + Clone> Foo<T<|>> where T: Sized {}
+"#,
+            expect![[r#"
+                *T*
+
+                ```rust
+                T: Copy + Clone + Sized
+                ```
+            "#]],
+        );
+        check(
+            r#"
+struct Foo<T>(T);
+impl<T> Foo<T<|>> {}
+"#,
+            expect![[r#"
+                *T*
+
+                ```rust
+                T
+                ```
+                "#]],
+        );
+        // lifetimes aren't being substituted yet
+        check(
+            r#"
+struct Foo<T>(T);
+impl<T: 'static> Foo<T<|>> {}
+"#,
+            expect![[r#"
+                *T*
+
+                ```rust
+                T: {error}
+                ```
+                "#]],
+        );
+    }
+
+    #[test]
+    fn hover_const_param() {
+        check(
+            r#"
+struct Foo<const LEN: usize>;
+impl<const LEN: usize> Foo<LEN<|>> {}
+"#,
+            expect![[r#"
+                *LEN*
+
+                ```rust
+                const LEN: usize
+                ```
+            "#]],
+        );
+    }
 }
diff --git a/crates/rust-analyzer/src/handlers.rs b/crates/rust-analyzer/src/handlers.rs
index dd486070b..c21ca044a 100644
--- a/crates/rust-analyzer/src/handlers.rs
+++ b/crates/rust-analyzer/src/handlers.rs
@@ -1648,7 +1648,7 @@ fn prepare_hover_actions(
     actions
         .iter()
         .filter_map(|it| match it {
-            HoverAction::Implementaion(position) => show_impl_command_link(snap, position),
+            HoverAction::Implementation(position) => show_impl_command_link(snap, position),
             HoverAction::Runnable(r) => runnable_action_links(snap, file_id, r.clone()),
             HoverAction::GoToType(targets) => goto_type_action_links(snap, targets),
         })