9 files changed, 277 insertions, 38 deletions

diff --git a/crates/ide/src/syntax_highlighting/inject.rs b/crates/ide/src/syntax_highlighting/inject.rs
index 00493a6b5..8e0940184 100644
--- a/crates/ide/src/syntax_highlighting/inject.rs
+++ b/crates/ide/src/syntax_highlighting/inject.rs
@@ -23,7 +23,7 @@ pub(super) fn ra_fixture(
     expanded: SyntaxToken,
 ) -> Option<()> {
     let active_parameter = ActiveParameter::at_token(&sema, expanded)?;
-    if !active_parameter.name.starts_with("ra_fixture") {
+    if !active_parameter.ident().map_or(false, |name| name.text().starts_with("ra_fixture")) {
         return None;
     }
     let value = literal.value()?;
diff --git a/crates/ide_completion/src/completions.rs b/crates/ide_completion/src/completions.rs
index 09882c4f3..cdac4e41a 100644
--- a/crates/ide_completion/src/completions.rs
+++ b/crates/ide_completion/src/completions.rs
@@ -2,25 +2,27 @@
 
 pub(crate) mod attribute;
 pub(crate) mod dot;
-pub(crate) mod record;
-pub(crate) mod pattern;
+pub(crate) mod flyimport;
 pub(crate) mod fn_param;
 pub(crate) mod keyword;
-pub(crate) mod snippet;
-pub(crate) mod qualified_path;
-pub(crate) mod unqualified_path;
-pub(crate) mod postfix;
+pub(crate) mod lifetime;
 pub(crate) mod macro_in_item_position;
-pub(crate) mod trait_impl;
 pub(crate) mod mod_;
-pub(crate) mod flyimport;
+pub(crate) mod pattern;
+pub(crate) mod postfix;
+pub(crate) mod qualified_path;
+pub(crate) mod record;
+pub(crate) mod snippet;
+pub(crate) mod trait_impl;
+pub(crate) mod unqualified_path;
 
 use std::iter;
 
 use hir::{known, ModPath, ScopeDef, Type};
+use ide_db::SymbolKind;
 
 use crate::{
-    item::Builder,
+    item::{Builder, CompletionKind},
     render::{
         const_::render_const,
         enum_variant::render_variant,
@@ -31,7 +33,7 @@ use crate::{
         type_alias::render_type_alias,
         RenderContext,
     },
-    CompletionContext, CompletionItem,
+    CompletionContext, CompletionItem, CompletionItemKind,
 };
 
 /// Represents an in-progress set of completions being built.
@@ -77,6 +79,13 @@ impl Completions {
         self.add(item);
     }
 
+    pub(crate) fn add_static_lifetime(&mut self, ctx: &CompletionContext) {
+        let mut item =
+            CompletionItem::new(CompletionKind::Reference, ctx.source_range(), "'static");
+        item.kind(CompletionItemKind::SymbolKind(SymbolKind::LifetimeParam));
+        self.add(item.build());
+    }
+
     pub(crate) fn add_resolution(
         &mut self,
         ctx: &CompletionContext,
diff --git a/crates/ide_completion/src/completions/lifetime.rs b/crates/ide_completion/src/completions/lifetime.rs
new file mode 100644
index 000000000..74eb23360
--- /dev/null
+++ b/crates/ide_completion/src/completions/lifetime.rs
@@ -0,0 +1,181 @@
+//! Completes lifetimes.
+use hir::ScopeDef;
+
+use crate::{completions::Completions, context::CompletionContext};
+
+/// Completes lifetimes.
+pub(crate) fn complete_lifetime(acc: &mut Completions, ctx: &CompletionContext) {
+    if !ctx.lifetime_allowed {
+        return;
+    }
+    let param_lifetime = match (
+        &ctx.lifetime_syntax,
+        ctx.lifetime_param_syntax.as_ref().and_then(|lp| lp.lifetime()),
+    ) {
+        (Some(lt), Some(lp)) if lp == lt.clone() => return,
+        (Some(_), Some(lp)) => Some(lp.to_string()),
+        _ => None,
+    };
+
+    ctx.scope.process_all_names(&mut |name, res| {
+        if let ScopeDef::GenericParam(hir::GenericParam::LifetimeParam(_)) = res {
+            if param_lifetime != Some(name.to_string()) {
+                acc.add_resolution(ctx, name.to_string(), &res);
+            }
+        }
+    });
+    if param_lifetime.is_none() {
+        acc.add_static_lifetime(ctx);
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use expect_test::{expect, Expect};
+
+    use crate::{
+        test_utils::{check_edit, completion_list_with_config, TEST_CONFIG},
+        CompletionConfig, CompletionKind,
+    };
+
+    fn check(ra_fixture: &str, expect: Expect) {
+        check_with_config(TEST_CONFIG, ra_fixture, expect);
+    }
+
+    fn check_with_config(config: CompletionConfig, ra_fixture: &str, expect: Expect) {
+        let actual = completion_list_with_config(config, ra_fixture, CompletionKind::Reference);
+        expect.assert_eq(&actual)
+    }
+
+    #[test]
+    fn check_lifetime_edit() {
+        check_edit(
+            "'lifetime",
+            r#"
+fn func<'lifetime>(foo: &'li$0) {}
+"#,
+            r#"
+fn func<'lifetime>(foo: &'lifetime) {}
+"#,
+        );
+    }
+
+    #[test]
+    fn complete_lifetime_in_ref() {
+        check(
+            r#"
+fn foo<'lifetime>(foo: &'a$0 usize) {}
+"#,
+            expect![[r#"
+                lt 'lifetime
+                lt 'static
+            "#]],
+        );
+    }
+
+    #[test]
+    fn complete_lifetime_in_ref_missing_ty() {
+        check(
+            r#"
+fn foo<'lifetime>(foo: &'a$0) {}
+"#,
+            expect![[r#"
+                lt 'lifetime
+                lt 'static
+            "#]],
+        );
+    }
+    #[test]
+    fn complete_lifetime_in_self_ref() {
+        check(
+            r#"
+struct Foo;
+impl<'impl> Foo {
+    fn foo<'func>(&'a$0 self) {}
+}
+"#,
+            expect![[r#"
+                lt 'func
+                lt 'impl
+                lt 'static
+            "#]],
+        );
+    }
+
+    #[test]
+    fn complete_lifetime_in_arg_list() {
+        check(
+            r#"
+struct Foo<'lt>;
+fn foo<'lifetime>(_: Foo<'a$0>) {}
+"#,
+            expect![[r#"
+                lt 'lifetime
+                lt 'static
+            "#]],
+        );
+    }
+
+    #[test]
+    fn complete_lifetime_in_where_pred() {
+        check(
+            r#"
+fn foo2<'lifetime, T>() where 'a$0 {}
+"#,
+            expect![[r#"
+                lt 'lifetime
+                lt 'static
+            "#]],
+        );
+    }
+
+    #[test]
+    fn complete_lifetime_in_ty_bound() {
+        check(
+            r#"
+fn foo2<'lifetime, T>() where T: 'a$0 {}
+"#,
+            expect![[r#"
+                lt 'lifetime
+                lt 'static
+            "#]],
+        );
+        check(
+            r#"
+fn foo2<'lifetime, T>() where T: Trait<'a$0> {}
+"#,
+            expect![[r#"
+                lt 'lifetime
+                lt 'static
+            "#]],
+        );
+    }
+
+    #[test]
+    fn dont_complete_lifetime_in_assoc_ty_bound() {
+        check(
+            r#"
+fn foo2<'lifetime, T>() where T: Trait<Item = 'a$0> {}
+"#,
+            expect![[r#""#]],
+        );
+    }
+
+    #[test]
+    fn complete_lifetime_in_param_list() {
+        check(
+            r#"
+fn foo<'a$0>() {}
+"#,
+            expect![[r#""#]],
+        );
+        check(
+            r#"
+fn foo<'footime, 'lifetime: 'a$0>() {}
+"#,
+            expect![[r#"
+                lt 'footime
+            "#]],
+        );
+    }
+}
diff --git a/crates/ide_completion/src/completions/pattern.rs b/crates/ide_completion/src/completions/pattern.rs
index 476eecff0..b06498e6d 100644
--- a/crates/ide_completion/src/completions/pattern.rs
+++ b/crates/ide_completion/src/completions/pattern.rs
@@ -1,4 +1,4 @@
-//! Completes constats and paths in patterns.
+//! Completes constants and paths in patterns.
 
 use crate::{CompletionContext, Completions};
 
diff --git a/crates/ide_completion/src/context.rs b/crates/ide_completion/src/context.rs
index 6d57da06a..4c2b31084 100644
--- a/crates/ide_completion/src/context.rs
+++ b/crates/ide_completion/src/context.rs
@@ -4,8 +4,11 @@ use hir::{Local, ScopeDef, Semantics, SemanticsScope, Type};
 use ide_db::base_db::{FilePosition, SourceDatabase};
 use ide_db::{call_info::ActiveParameter, RootDatabase};
 use syntax::{
-    algo::find_node_at_offset, ast, match_ast, AstNode, NodeOrToken, SyntaxKind::*, SyntaxNode,
-    SyntaxToken, TextRange, TextSize,
+    algo::find_node_at_offset,
+    ast::{self, NameOrNameRef, NameOwner},
+    match_ast, AstNode, NodeOrToken,
+    SyntaxKind::*,
+    SyntaxNode, SyntaxToken, TextRange, TextSize,
 };
 
 use text_edit::Indel;
@@ -35,15 +38,18 @@ pub(crate) struct CompletionContext<'a> {
     /// The token before the cursor, in the macro-expanded file.
     pub(super) token: SyntaxToken,
     pub(super) krate: Option<hir::Crate>,
-    pub(super) expected_name: Option<String>,
+    pub(super) expected_name: Option<NameOrNameRef>,
     pub(super) expected_type: Option<Type>,
     pub(super) name_ref_syntax: Option<ast::NameRef>,
+    pub(super) lifetime_syntax: Option<ast::Lifetime>,
+    pub(super) lifetime_param_syntax: Option<ast::LifetimeParam>,
     pub(super) function_syntax: Option<ast::Fn>,
     pub(super) use_item_syntax: Option<ast::Use>,
     pub(super) record_lit_syntax: Option<ast::RecordExpr>,
     pub(super) record_pat_syntax: Option<ast::RecordPat>,
     pub(super) record_field_syntax: Option<ast::RecordExprField>,
     pub(super) impl_def: Option<ast::Impl>,
+    pub(super) lifetime_allowed: bool,
     /// FIXME: `ActiveParameter` is string-based, which is very very wrong
     pub(super) active_parameter: Option<ActiveParameter>,
     pub(super) is_param: bool,
@@ -136,9 +142,12 @@ impl<'a> CompletionContext<'a> {
             original_token,
             token,
             krate,
+            lifetime_allowed: false,
             expected_name: None,
             expected_type: None,
             name_ref_syntax: None,
+            lifetime_syntax: None,
+            lifetime_param_syntax: None,
             function_syntax: None,
             use_item_syntax: None,
             record_lit_syntax: None,
@@ -241,7 +250,7 @@ impl<'a> CompletionContext<'a> {
     pub(crate) fn source_range(&self) -> TextRange {
         // check kind of macro-expanded token, but use range of original token
         let kind = self.token.kind();
-        if kind == IDENT || kind == UNDERSCORE || kind.is_keyword() {
+        if kind == IDENT || kind == LIFETIME_IDENT || kind == UNDERSCORE || kind.is_keyword() {
             cov_mark::hit!(completes_if_prefix_is_keyword);
             self.original_token.text_range()
         } else {
@@ -292,13 +301,13 @@ impl<'a> CompletionContext<'a> {
         file_with_fake_ident: SyntaxNode,
         offset: TextSize,
     ) {
-        let expected = {
+        let (expected_type, expected_name) = {
             let mut node = match self.token.parent() {
                 Some(it) => it,
                 None => return,
             };
             loop {
-                let ret = match_ast! {
+                break match_ast! {
                     match node {
                         ast::LetStmt(it) => {
                             cov_mark::hit!(expected_type_let_with_leading_char);
@@ -306,7 +315,7 @@ impl<'a> CompletionContext<'a> {
                             let ty = it.pat()
                                 .and_then(|pat| self.sema.type_of_pat(&pat));
                             let name = if let Some(ast::Pat::IdentPat(ident)) = it.pat() {
-                                Some(ident.syntax().text().to_string())
+                                ident.name().map(NameOrNameRef::Name)
                             } else {
                                 None
                             };
@@ -319,7 +328,10 @@ impl<'a> CompletionContext<'a> {
                             ActiveParameter::at_token(
                                 &self.sema,
                                 self.token.clone(),
-                            ).map(|ap| (Some(ap.ty), Some(ap.name)))
+                            ).map(|ap| {
+                                let name = ap.ident().map(NameOrNameRef::Name);
+                                (Some(ap.ty), name)
+                            })
                             .unwrap_or((None, None))
                         },
                         ast::RecordExprFieldList(_it) => {
@@ -327,10 +339,10 @@ impl<'a> CompletionContext<'a> {
                             self.token.prev_sibling_or_token()
                                 .and_then(|se| se.into_node())
                                 .and_then(|node| ast::RecordExprField::cast(node))
-                                .and_then(|rf| self.sema.resolve_record_field(&rf))
-                                .map(|f|(
+                                .and_then(|rf| self.sema.resolve_record_field(&rf).zip(Some(rf)))
+                                .map(|(f, rf)|(
                                     Some(f.0.signature_ty(self.db)),
-                                    Some(f.0.name(self.db).to_string()),
+                                    rf.field_name().map(NameOrNameRef::NameRef),
                                 ))
                                 .unwrap_or((None, None))
                         },
@@ -340,7 +352,7 @@ impl<'a> CompletionContext<'a> {
                                 .resolve_record_field(&it)
                                 .map(|f|(
                                     Some(f.0.signature_ty(self.db)),
-                                    Some(f.0.name(self.db).to_string()),
+                                    it.field_name().map(NameOrNameRef::NameRef),
                                 ))
                                 .unwrap_or((None, None))
                         },
@@ -378,14 +390,17 @@ impl<'a> CompletionContext<'a> {
                         },
                     }
                 };
-
-                break ret;
             }
         };
-        self.expected_type = expected.0;
-        self.expected_name = expected.1;
+        self.expected_type = expected_type;
+        self.expected_name = expected_name;
         self.attribute_under_caret = find_node_at_offset(&file_with_fake_ident, offset);
 
+        if let Some(lifetime) = find_node_at_offset::<ast::Lifetime>(&file_with_fake_ident, offset)
+        {
+            self.classify_lifetime(original_file, lifetime, offset);
+        }
+
         // First, let's try to complete a reference to some declaration.
         if let Some(name_ref) = find_node_at_offset::<ast::NameRef>(&file_with_fake_ident, offset) {
             // Special case, `trait T { fn foo(i_am_a_name_ref) {} }`.
@@ -445,6 +460,23 @@ impl<'a> CompletionContext<'a> {
         }
     }
 
+    fn classify_lifetime(
+        &mut self,
+        original_file: &SyntaxNode,
+        lifetime: ast::Lifetime,
+        offset: TextSize,
+    ) {
+        self.lifetime_syntax =
+            find_node_at_offset(original_file, lifetime.syntax().text_range().start());
+        if lifetime.syntax().parent().map_or(false, |p| p.kind() != syntax::SyntaxKind::ERROR) {
+            self.lifetime_allowed = true;
+        }
+        if let Some(_) = lifetime.syntax().parent().and_then(ast::LifetimeParam::cast) {
+            self.lifetime_param_syntax =
+                self.sema.find_node_at_offset_with_macros(original_file, offset);
+        }
+    }
+
     fn classify_name_ref(
         &mut self,
         original_file: &SyntaxNode,
@@ -452,11 +484,11 @@ impl<'a> CompletionContext<'a> {
         offset: TextSize,
     ) {
         self.name_ref_syntax =
-            find_node_at_offset(&original_file, name_ref.syntax().text_range().start());
+            find_node_at_offset(original_file, name_ref.syntax().text_range().start());
         let name_range = name_ref.syntax().text_range();
         if ast::RecordExprField::for_field_name(&name_ref).is_some() {
             self.record_lit_syntax =
-                self.sema.find_node_at_offset_with_macros(&original_file, offset);
+                self.sema.find_node_at_offset_with_macros(original_file, offset);
         }
 
         self.fill_impl_def();
@@ -631,7 +663,9 @@ mod tests {
             .map(|t| t.display_test(&db).to_string())
             .unwrap_or("?".to_owned());
 
-        let name = completion_context.expected_name.unwrap_or("?".to_owned());
+        let name = completion_context
+            .expected_name
+            .map_or_else(|| "?".to_owned(), |name| name.to_string());
 
         expect.assert_eq(&format!("ty: {}, name: {}", ty, name));
     }
diff --git a/crates/ide_completion/src/lib.rs b/crates/ide_completion/src/lib.rs
index d9ea7b7ea..7a0eb6a96 100644
--- a/crates/ide_completion/src/lib.rs
+++ b/crates/ide_completion/src/lib.rs
@@ -130,6 +130,7 @@ pub fn completions(
     completions::trait_impl::complete_trait_impl(&mut acc, &ctx);
     completions::mod_::complete_mod(&mut acc, &ctx);
     completions::flyimport::import_on_the_fly(&mut acc, &ctx);
+    completions::lifetime::complete_lifetime(&mut acc, &ctx);
 
     Some(acc)
 }
diff --git a/crates/ide_completion/src/render.rs b/crates/ide_completion/src/render.rs
index 12921e12b..2b6e9ebd1 100644
--- a/crates/ide_completion/src/render.rs
+++ b/crates/ide_completion/src/render.rs
@@ -243,7 +243,7 @@ impl<'a> Render<'a> {
 
             item.set_relevance(CompletionRelevance {
                 exact_type_match: compute_exact_type_match(self.ctx.completion, &ty),
-                exact_name_match: compute_exact_name_match(self.ctx.completion, local_name.clone()),
+                exact_name_match: compute_exact_name_match(self.ctx.completion, &local_name),
                 is_local: true,
                 ..CompletionRelevance::default()
             });
@@ -319,8 +319,7 @@ fn compute_exact_type_match(ctx: &CompletionContext, completion_ty: &hir::Type)
 
 fn compute_exact_name_match(ctx: &CompletionContext, completion_name: impl Into<String>) -> bool {
     let completion_name = completion_name.into();
-
-    Some(&completion_name) == ctx.expected_name.as_ref()
+    ctx.expected_name.as_ref().map_or(false, |name| name.text() == completion_name)
 }
 
 fn compute_ref_match(ctx: &CompletionContext, completion_ty: &hir::Type) -> Option<Mutability> {
diff --git a/crates/ide_db/src/call_info.rs b/crates/ide_db/src/call_info.rs
index 7e26c3ccf..e583a52f4 100644
--- a/crates/ide_db/src/call_info.rs
+++ b/crates/ide_db/src/call_info.rs
@@ -4,7 +4,7 @@ use either::Either;
 use hir::{HasAttrs, HirDisplay, Semantics, Type};
 use stdx::format_to;
 use syntax::{
-    ast::{self, ArgListOwner},
+    ast::{self, ArgListOwner, NameOwner},
     match_ast, AstNode, SyntaxNode, SyntaxToken, TextRange, TextSize,
 };
 
@@ -142,7 +142,7 @@ fn call_info_impl(
 #[derive(Debug)]
 pub struct ActiveParameter {
     pub ty: Type,
-    pub name: String,
+    pub pat: Either<ast::SelfParam, ast::Pat>,
 }
 
 impl ActiveParameter {
@@ -165,8 +165,14 @@ impl ActiveParameter {
             return None;
         }
         let (pat, ty) = params.swap_remove(idx);
-        let name = pat?.to_string();
-        Some(ActiveParameter { ty, name })
+        pat.map(|pat| ActiveParameter { ty, pat })
+    }
+
+    pub fn ident(&self) -> Option<ast::Name> {
+        self.pat.as_ref().right().and_then(|param| match param {
+            ast::Pat::IdentPat(ident) => ident.name(),
+            _ => None,
+        })
     }
 }
 
diff --git a/crates/syntax/src/ast/node_ext.rs b/crates/syntax/src/ast/node_ext.rs
index 01f580a40..42a7b9c2a 100644
--- a/crates/syntax/src/ast/node_ext.rs
+++ b/crates/syntax/src/ast/node_ext.rs
@@ -380,6 +380,15 @@ impl fmt::Display for NameOrNameRef {
     }
 }
 
+impl NameOrNameRef {
+    pub fn text(&self) -> &str {
+        match self {
+            NameOrNameRef::Name(name) => name.text(),
+            NameOrNameRef::NameRef(name_ref) => name_ref.text(),
+        }
+    }
+}
+
 impl ast::RecordPatField {
     pub fn for_field_name_ref(field_name: &ast::NameRef) -> Option<ast::RecordPatField> {
         let candidate = field_name.syntax().parent().and_then(ast::RecordPatField::cast)?;