8 files changed, 265 insertions, 22 deletions

diff --git a/crates/ide/src/display/navigation_target.rs b/crates/ide/src/display/navigation_target.rs
index 234f80a3a..ce0f4214c 100644
--- a/crates/ide/src/display/navigation_target.rs
+++ b/crates/ide/src/display/navigation_target.rs
@@ -9,7 +9,7 @@ use ide_db::{defs::Definition, RootDatabase};
 use syntax::{
     ast::{self, NameOwner},
     match_ast, AstNode, SmolStr,
-    SyntaxKind::{self, IDENT_PAT, TYPE_PARAM},
+    SyntaxKind::{self, IDENT_PAT, LIFETIME_PARAM, TYPE_PARAM},
     TextRange,
 };
 
@@ -182,6 +182,7 @@ impl TryToNav for Definition {
             Definition::SelfType(it) => Some(it.to_nav(db)),
             Definition::Local(it) => Some(it.to_nav(db)),
             Definition::TypeParam(it) => Some(it.to_nav(db)),
+            Definition::LifetimeParam(it) => Some(it.to_nav(db)),
         }
     }
 }
@@ -376,6 +377,23 @@ impl ToNav for hir::TypeParam {
     }
 }
 
+impl ToNav for hir::LifetimeParam {
+    fn to_nav(&self, db: &RootDatabase) -> NavigationTarget {
+        let src = self.source(db);
+        let full_range = src.value.syntax().text_range();
+        NavigationTarget {
+            file_id: src.file_id.original_file(db),
+            name: self.name(db).to_string().into(),
+            kind: LIFETIME_PARAM,
+            full_range,
+            focus_range: Some(full_range),
+            container_name: None,
+            description: None,
+            docs: None,
+        }
+    }
+}
+
 pub(crate) fn docs_from_symbol(db: &RootDatabase, symbol: &FileSymbol) -> Option<Documentation> {
     let parse = db.parse(symbol.file_id);
     let node = symbol.ptr.to_node(parse.tree().syntax());
diff --git a/crates/ide/src/doc_links.rs b/crates/ide/src/doc_links.rs
index 10263537a..2b5794a31 100644
--- a/crates/ide/src/doc_links.rs
+++ b/crates/ide/src/doc_links.rs
@@ -190,7 +190,10 @@ fn rewrite_intra_doc_link(
         },
         Definition::Macro(it) => it.resolve_doc_path(db, link, ns),
         Definition::Field(it) => it.resolve_doc_path(db, link, ns),
-        Definition::SelfType(_) | Definition::Local(_) | Definition::TypeParam(_) => return None,
+        Definition::SelfType(_)
+        | Definition::Local(_)
+        | Definition::TypeParam(_)
+        | Definition::LifetimeParam(_) => return None,
     }?;
     let krate = resolved.module(db)?.krate();
     let canonical_path = resolved.canonical_path(db)?;
diff --git a/crates/ide/src/goto_definition.rs b/crates/ide/src/goto_definition.rs
index b9810457f..173509b08 100644
--- a/crates/ide/src/goto_definition.rs
+++ b/crates/ide/src/goto_definition.rs
@@ -1,3 +1,4 @@
+use either::Either;
 use hir::Semantics;
 use ide_db::{
     base_db::FileId,
@@ -33,7 +34,7 @@ pub(crate) fn goto_definition(
     let nav_targets = match_ast! {
         match parent {
             ast::NameRef(name_ref) => {
-                reference_definition(&sema, &name_ref).to_vec()
+                reference_definition(&sema, Either::Right(&name_ref)).to_vec()
             },
             ast::Name(name) => {
                 let def = NameClass::classify(&sema, &name)?.referenced_or_defined(sema.db);
@@ -53,6 +54,13 @@ pub(crate) fn goto_definition(
                 let self_param = func.param_list()?.self_param()?;
                 vec![self_to_nav_target(self_param, position.file_id)?]
             },
+            ast::Lifetime(lt) => if let Some(name_class) = NameClass::classify_lifetime(&sema, &lt) {
+                let def = name_class.referenced_or_defined(sema.db);
+                let nav = def.try_to_nav(sema.db)?;
+                vec![nav]
+            } else {
+                reference_definition(&sema, Either::Left(&lt)).to_vec()
+            },
             _ => return None,
         }
     };
@@ -64,7 +72,7 @@ fn pick_best(tokens: TokenAtOffset<SyntaxToken>) -> Option<SyntaxToken> {
     return tokens.max_by_key(priority);
     fn priority(n: &SyntaxToken) -> usize {
         match n.kind() {
-            IDENT | INT_NUMBER | T![self] => 2,
+            IDENT | INT_NUMBER | LIFETIME_IDENT | T![self] => 2,
             kind if kind.is_trivia() => 0,
             _ => 1,
         }
@@ -102,9 +110,12 @@ impl ReferenceResult {
 
 pub(crate) fn reference_definition(
     sema: &Semantics<RootDatabase>,
-    name_ref: &ast::NameRef,
+    name_ref: Either<&ast::Lifetime, &ast::NameRef>,
 ) -> ReferenceResult {
-    let name_kind = NameRefClass::classify(sema, name_ref);
+    let name_kind = name_ref.either(
+        |lifetime| NameRefClass::classify_lifetime(sema, lifetime),
+        |name_ref| NameRefClass::classify(sema, name_ref),
+    );
     if let Some(def) = name_kind {
         let def = def.referenced(sema.db);
         return match def.try_to_nav(sema.db) {
@@ -114,10 +125,9 @@ pub(crate) fn reference_definition(
     }
 
     // Fallback index based approach:
-    let navs = symbol_index::index_resolve(sema.db, name_ref)
-        .into_iter()
-        .map(|s| s.to_nav(sema.db))
-        .collect();
+    let name = name_ref.either(ast::Lifetime::text, ast::NameRef::text);
+    let navs =
+        symbol_index::index_resolve(sema.db, name).into_iter().map(|s| s.to_nav(sema.db)).collect();
     ReferenceResult::Approximate(navs)
 }
 
@@ -1036,4 +1046,35 @@ impl Foo {
 }"#,
         )
     }
+
+    #[test]
+    fn goto_lifetime_param_on_decl() {
+        check(
+            r#"
+fn foo<'foobar<|>>(_: &'foobar ()) {
+     //^^^^^^^
+}"#,
+        )
+    }
+
+    #[test]
+    fn goto_lifetime_param_decl() {
+        check(
+            r#"
+fn foo<'foobar>(_: &'foobar<|> ()) {
+     //^^^^^^^
+}"#,
+        )
+    }
+
+    #[test]
+    fn goto_lifetime_param_decl_nested() {
+        check(
+            r#"
+fn foo<'foobar>(_: &'foobar ()) {
+    fn foo<'foobar>(_: &'foobar<|> ()) {}
+         //^^^^^^^
+}"#,
+        )
+    }
 }
diff --git a/crates/ide/src/hover.rs b/crates/ide/src/hover.rs
index ab017d2ad..a01b0c894 100644
--- a/crates/ide/src/hover.rs
+++ b/crates/ide/src/hover.rs
@@ -364,7 +364,7 @@ fn hover_for_definition(db: &RootDatabase, def: Definition) -> Option<Markup> {
                 Adt::Enum(it) => from_def_source(db, it, mod_path),
             })
         }
-        Definition::TypeParam(_) => {
+        Definition::TypeParam(_) | Definition::LifetimeParam(_) => {
             // FIXME: Hover for generic param
             None
         }
diff --git a/crates/ide/src/lib.rs b/crates/ide/src/lib.rs
index 71068cac2..c5c652cda 100644
--- a/crates/ide/src/lib.rs
+++ b/crates/ide/src/lib.rs
@@ -528,6 +528,13 @@ impl Analysis {
         self.with_db(|db| references::rename::rename(db, position, new_name))
     }
 
+    pub fn prepare_rename(
+        &self,
+        position: FilePosition,
+    ) -> Cancelable<Result<RangeInfo<()>, RenameError>> {
+        self.with_db(|db| references::rename::prepare_rename(db, position))
+    }
+
     pub fn structural_search_replace(
         &self,
         query: &str,
diff --git a/crates/ide/src/references.rs b/crates/ide/src/references.rs
index 675957fff..98190a86b 100644
--- a/crates/ide/src/references.rs
+++ b/crates/ide/src/references.rs
@@ -130,6 +130,8 @@ pub(crate) fn find_all_refs(
                 kind = ReferenceKind::FieldShorthandForLocal;
             }
         }
+    } else if let Definition::LifetimeParam(_) = def {
+        kind = ReferenceKind::Lifetime;
     };
 
     let declaration = Declaration { nav, kind, access: decl_access(&def, &syntax, decl_range) };
@@ -148,11 +150,29 @@ fn find_name(
         let range = name.syntax().text_range();
         return Some(RangeInfo::new(range, def));
     }
-    let name_ref =
-        sema.find_node_at_offset_with_descend::<ast::NameRef>(&syntax, position.offset)?;
-    let def = NameRefClass::classify(sema, &name_ref)?.referenced(sema.db);
-    let range = name_ref.syntax().text_range();
-    Some(RangeInfo::new(range, def))
+
+    let (text_range, def) = if let Some(lifetime) =
+        sema.find_node_at_offset_with_descend::<ast::Lifetime>(&syntax, position.offset)
+    {
+        if let Some(def) = NameRefClass::classify_lifetime(sema, &lifetime)
+            .map(|class| NameRefClass::referenced(class, sema.db))
+        {
+            (lifetime.syntax().text_range(), def)
+        } else {
+            (
+                lifetime.syntax().text_range(),
+                NameClass::classify_lifetime(sema, &lifetime)?.referenced_or_defined(sema.db),
+            )
+        }
+    } else {
+        let name_ref =
+            sema.find_node_at_offset_with_descend::<ast::NameRef>(&syntax, position.offset)?;
+        (
+            name_ref.syntax().text_range(),
+            NameRefClass::classify(sema, &name_ref)?.referenced(sema.db),
+        )
+    };
+    Some(RangeInfo::new(text_range, def))
 }
 
 fn decl_access(def: &Definition, syntax: &SyntaxNode, range: TextRange) -> Option<ReferenceAccess> {
@@ -1005,4 +1025,65 @@ impl Foo {
         }
         expect.assert_eq(&actual)
     }
+
+    #[test]
+    fn test_find_lifetimes_function() {
+        check(
+            r#"
+trait Foo<'a> {}
+impl<'a> Foo<'a> for &'a () {}
+fn foo<'a, 'b: 'a>(x: &'a<|> ()) -> &'a () where &'a (): Foo<'a> {
+    fn bar<'a>(_: &'a ()) {}
+    x
+}
+"#,
+            expect![[r#"
+                'a LIFETIME_PARAM FileId(0) 55..57 55..57 Lifetime
+
+                FileId(0) 63..65 Lifetime
+                FileId(0) 71..73 Lifetime
+                FileId(0) 82..84 Lifetime
+                FileId(0) 95..97 Lifetime
+                FileId(0) 106..108 Lifetime
+            "#]],
+        );
+    }
+
+    #[test]
+    fn test_find_lifetimes_type_alias() {
+        check(
+            r#"
+type Foo<'a, T> where T: 'a<|> = &'a T;
+"#,
+            expect![[r#"
+                'a LIFETIME_PARAM FileId(0) 9..11 9..11 Lifetime
+
+                FileId(0) 25..27 Lifetime
+                FileId(0) 31..33 Lifetime
+            "#]],
+        );
+    }
+
+    #[test]
+    fn test_find_lifetimes_trait_impl() {
+        check(
+            r#"
+trait Foo<'a> {
+    fn foo() -> &'a ();
+}
+impl<'a> Foo<'a> for &'a () {
+    fn foo() -> &'a<|> () {
+        unimplemented!()
+    }
+}
+"#,
+            expect![[r#"
+                'a LIFETIME_PARAM FileId(0) 47..49 47..49 Lifetime
+
+                FileId(0) 55..57 Lifetime
+                FileId(0) 64..66 Lifetime
+                FileId(0) 89..91 Lifetime
+            "#]],
+        );
+    }
 }
diff --git a/crates/ide/src/references/rename.rs b/crates/ide/src/references/rename.rs
index 44081f210..56e923841 100644
--- a/crates/ide/src/references/rename.rs
+++ b/crates/ide/src/references/rename.rs
@@ -35,6 +35,29 @@ impl fmt::Display for RenameError {
 
 impl Error for RenameError {}
 
+pub(crate) fn prepare_rename(
+    db: &RootDatabase,
+    position: FilePosition,
+) -> Result<RangeInfo<()>, RenameError> {
+    let sema = Semantics::new(db);
+    let source_file = sema.parse(position.file_id);
+    let syntax = source_file.syntax();
+    if let Some(module) = find_module_at_offset(&sema, position, syntax) {
+        rename_mod(&sema, position, module, "dummy")
+    } else if let Some(self_token) =
+        syntax.token_at_offset(position.offset).find(|t| t.kind() == SyntaxKind::SELF_KW)
+    {
+        rename_self_to_param(&sema, position, self_token, "dummy")
+    } else {
+        let range = match find_all_refs(&sema, position, None) {
+            Some(RangeInfo { range, .. }) => range,
+            None => return Err(RenameError("No references found at position".to_string())),
+        };
+        Ok(RangeInfo::new(range, SourceChange::from(vec![])))
+    }
+    .map(|info| RangeInfo::new(info.range, ()))
+}
+
 pub(crate) fn rename(
     db: &RootDatabase,
     position: FilePosition,
@@ -49,11 +72,18 @@ pub(crate) fn rename_with_semantics(
     position: FilePosition,
     new_name: &str,
 ) -> Result<RangeInfo<SourceChange>, RenameError> {
-    match lex_single_syntax_kind(new_name) {
+    let is_lifetime_name = match lex_single_syntax_kind(new_name) {
         Some(res) => match res {
-            (SyntaxKind::IDENT, _) => (),
-            (SyntaxKind::UNDERSCORE, _) => (),
+            (SyntaxKind::IDENT, _) => false,
+            (SyntaxKind::UNDERSCORE, _) => false,
             (SyntaxKind::SELF_KW, _) => return rename_to_self(&sema, position),
+            (SyntaxKind::LIFETIME_IDENT, _) if new_name != "'static" && new_name != "'_" => true,
+            (SyntaxKind::LIFETIME_IDENT, _) => {
+                return Err(RenameError(format!(
+                    "Invalid name `{0}`: Cannot rename lifetime to {0}",
+                    new_name
+                )))
+            }
             (_, Some(syntax_error)) => {
                 return Err(RenameError(format!("Invalid name `{}`: {}", new_name, syntax_error)))
             }
@@ -62,18 +92,21 @@ pub(crate) fn rename_with_semantics(
             }
         },
         None => return Err(RenameError(format!("Invalid name `{}`: not an identifier", new_name))),
-    }
+    };
 
     let source_file = sema.parse(position.file_id);
     let syntax = source_file.syntax();
-    if let Some(module) = find_module_at_offset(&sema, position, syntax) {
+    // this is here to prevent lifetime renames from happening on modules and self
+    if is_lifetime_name {
+        rename_reference(&sema, position, new_name, is_lifetime_name)
+    } else if let Some(module) = find_module_at_offset(&sema, position, syntax) {
         rename_mod(&sema, position, module, new_name)
     } else if let Some(self_token) =
         syntax.token_at_offset(position.offset).find(|t| t.kind() == SyntaxKind::SELF_KW)
     {
         rename_self_to_param(&sema, position, self_token, new_name)
     } else {
-        rename_reference(&sema, position, new_name)
+        rename_reference(&sema, position, new_name, is_lifetime_name)
     }
 }
 
@@ -355,12 +388,26 @@ fn rename_reference(
     sema: &Semantics<RootDatabase>,
     position: FilePosition,
     new_name: &str,
+    is_lifetime_name: bool,
 ) -> Result<RangeInfo<SourceChange>, RenameError> {
     let RangeInfo { range, info: refs } = match find_all_refs(sema, position, None) {
         Some(range_info) => range_info,
         None => return Err(RenameError("No references found at position".to_string())),
     };
 
+    match (refs.declaration.kind == ReferenceKind::Lifetime, is_lifetime_name) {
+        (true, false) => {
+            return Err(RenameError(format!(
+                "Invalid name `{}`: not a lifetime identifier",
+                new_name
+            )))
+        }
+        (false, true) => {
+            return Err(RenameError(format!("Invalid name `{}`: not an identifier", new_name)))
+        }
+        _ => (),
+    }
+
     let edit = refs
         .into_iter()
         .map(|reference| source_edit_from_reference(sema, reference, new_name))
@@ -465,6 +512,24 @@ mod tests {
     }
 
     #[test]
+    fn test_rename_to_invalid_identifier_lifetime() {
+        check(
+            "'foo",
+            r#"fn main() { let i<|> = 1; }"#,
+            "error: Invalid name `'foo`: not an identifier",
+        );
+    }
+
+    #[test]
+    fn test_rename_to_invalid_identifier_lifetime2() {
+        check(
+            "foo",
+            r#"fn main<'a>(_: &'a<|> ()) {}"#,
+            "error: Invalid name `foo`: not a lifetime identifier",
+        );
+    }
+
+    #[test]
     fn test_rename_for_local() {
         check(
             "k",
@@ -1396,4 +1461,31 @@ fn foo(Foo { i: bar }: foo) -> i32 {
 "#,
         )
     }
+
+    #[test]
+    fn test_rename_lifetimes() {
+        check(
+            "'yeeee",
+            r#"
+trait Foo<'a> {
+    fn foo() -> &'a ();
+}
+impl<'a> Foo<'a> for &'a () {
+    fn foo() -> &'a<|> () {
+        unimplemented!()
+    }
+}
+"#,
+            r#"
+trait Foo<'a> {
+    fn foo() -> &'a ();
+}
+impl<'yeeee> Foo<'yeeee> for &'yeeee () {
+    fn foo() -> &'yeeee () {
+        unimplemented!()
+    }
+}
+"#,
+        )
+    }
 }
diff --git a/crates/ide/src/syntax_highlighting.rs b/crates/ide/src/syntax_highlighting.rs
index 990b0f7d9..488969f1a 100644
--- a/crates/ide/src/syntax_highlighting.rs
+++ b/crates/ide/src/syntax_highlighting.rs
@@ -806,6 +806,7 @@ fn highlight_def(db: &RootDatabase, def: Definition) -> Highlight {
             }
             return h;
         }
+        Definition::LifetimeParam(_) => HighlightTag::Lifetime,
     }
     .into()
 }