7 files changed, 257 insertions, 44 deletions

diff --git a/crates/ide/src/goto_definition.rs b/crates/ide/src/goto_definition.rs
index d41dd3d92..b9810457f 100644
--- a/crates/ide/src/goto_definition.rs
+++ b/crates/ide/src/goto_definition.rs
@@ -1,5 +1,6 @@
 use hir::Semantics;
 use ide_db::{
+    base_db::FileId,
     defs::{NameClass, NameRefClass},
     symbol_index, RootDatabase,
 };
@@ -40,10 +41,17 @@ pub(crate) fn goto_definition(
                 vec![nav]
             },
             ast::SelfParam(self_param) => {
-                let ty = sema.type_of_self(&self_param)?;
-                let adt_def = ty.autoderef(db).filter_map(|ty| ty.as_adt()).last()?;
-                let nav = adt_def.to_nav(db);
-                vec![nav]
+                vec![self_to_nav_target(self_param, position.file_id)?]
+            },
+            ast::PathSegment(segment) => {
+                segment.self_token()?;
+                let path = segment.parent_path();
+                if path.qualifier().is_some() && !ast::PathExpr::can_cast(path.syntax().parent()?.kind()) {
+                    return None;
+                }
+                let func = segment.syntax().ancestors().find_map(ast::Fn::cast)?;
+                let self_param = func.param_list()?.self_param()?;
+                vec![self_to_nav_target(self_param, position.file_id)?]
             },
             _ => return None,
         }
@@ -63,6 +71,20 @@ fn pick_best(tokens: TokenAtOffset<SyntaxToken>) -> Option<SyntaxToken> {
     }
 }
 
+fn self_to_nav_target(self_param: ast::SelfParam, file_id: FileId) -> Option<NavigationTarget> {
+    let self_token = self_param.self_token()?;
+    Some(NavigationTarget {
+        file_id,
+        full_range: self_param.syntax().text_range(),
+        focus_range: Some(self_token.text_range()),
+        name: self_token.text().clone(),
+        kind: self_token.kind(),
+        container_name: None,
+        description: None,
+        docs: None,
+    })
+}
+
 #[derive(Debug)]
 pub(crate) enum ReferenceResult {
     Exact(NavigationTarget),
@@ -987,31 +1009,31 @@ fn g() -> <() as Iterator<A = (), B<|> = u8>>::A {}
     }
 
     #[test]
-    fn todo_def_type_for_self() {
+    fn goto_self_param_ty_specified() {
         check(
             r#"
 struct Foo {}
-     //^^^
 
 impl Foo {
-    fn bar(&self<|>) {}
-}
-"#,
-        );
+    fn bar(self: &Foo) {
+         //^^^^
+        let foo = sel<|>f;
+    }
+}"#,
+        )
     }
 
     #[test]
-    fn todo_def_type_for_arbitrary_self() {
+    fn goto_self_param_on_decl() {
         check(
             r#"
-struct Arc<T>(T);
-     //^^^
 struct Foo {}
 
 impl Foo {
-    fn bar(self<|>: Arc<Self>) {}
-}
-"#,
-        );
+    fn bar(&self<|>) {
+          //^^^^
+    }
+}"#,
+        )
     }
 }
diff --git a/crates/ide/src/hover.rs b/crates/ide/src/hover.rs
index 832192881..94ad800a0 100644
--- a/crates/ide/src/hover.rs
+++ b/crates/ide/src/hover.rs
@@ -139,14 +139,17 @@ pub(crate) fn hover(
         }
     }
 
-    let node = token
-        .ancestors()
-        .find(|n| ast::Expr::cast(n.clone()).is_some() || ast::Pat::cast(n.clone()).is_some())?;
+    let node = token.ancestors().find(|n| {
+        ast::Expr::can_cast(n.kind())
+            || ast::Pat::can_cast(n.kind())
+            || ast::SelfParam::can_cast(n.kind())
+    })?;
 
     let ty = match_ast! {
         match node {
             ast::Expr(it) => sema.type_of_expr(&it)?,
             ast::Pat(it) => sema.type_of_pat(&it)?,
+            ast::SelfParam(self_param) => sema.type_of_self(&self_param)?,
             // If this node is a MACRO_CALL, it means that `descend_into_macros` failed to resolve.
             // (e.g expanding a builtin macro). So we give up here.
             ast::MacroCall(_it) => return None,
@@ -3282,4 +3285,41 @@ fn main() {
             "#]],
         );
     }
+
+    #[test]
+    fn hover_self_param_shows_type() {
+        check(
+            r#"
+struct Foo {}
+impl Foo {
+    fn bar(&sel<|>f) {}
+}
+"#,
+            expect![[r#"
+                *&self*
+                ```rust
+                &Foo
+                ```
+            "#]],
+        );
+    }
+
+    #[test]
+    fn hover_self_param_shows_type_for_arbitrary_self_type() {
+        check(
+            r#"
+struct Arc<T>(T);
+struct Foo {}
+impl Foo {
+    fn bar(sel<|>f: Arc<Foo>) {}
+}
+"#,
+            expect![[r#"
+                *self: Arc<Foo>*
+                ```rust
+                Arc<Foo>
+                ```
+            "#]],
+        );
+    }
 }
diff --git a/crates/ide/src/references/rename.rs b/crates/ide/src/references/rename.rs
index 91c64bd4a..731457696 100644
--- a/crates/ide/src/references/rename.rs
+++ b/crates/ide/src/references/rename.rs
@@ -221,24 +221,47 @@ fn rename_to_self(
     let source_file = sema.parse(position.file_id);
     let syn = source_file.syntax();
 
-    let fn_def = find_node_at_offset::<ast::Fn>(syn, position.offset)
+    let (fn_def, fn_ast) = find_node_at_offset::<ast::Fn>(syn, position.offset)
+        .and_then(|fn_ast| sema.to_def(&fn_ast).zip(Some(fn_ast)))
         .ok_or_else(|| RenameError("No surrounding method declaration found".to_string()))?;
-    let params =
-        fn_def.param_list().ok_or_else(|| RenameError("Method has no parameters".to_string()))?;
-    if params.self_param().is_some() {
+    let param_range = fn_ast
+        .param_list()
+        .and_then(|p| p.params().next())
+        .ok_or_else(|| RenameError("Method has no parameters".to_string()))?
+        .syntax()
+        .text_range();
+    if !param_range.contains(position.offset) {
+        return Err(RenameError("Only the first parameter can be self".to_string()));
+    }
+
+    let impl_block = find_node_at_offset::<ast::Impl>(syn, position.offset)
+        .and_then(|def| sema.to_def(&def))
+        .ok_or_else(|| RenameError("No impl block found for function".to_string()))?;
+    if fn_def.self_param(sema.db).is_some() {
         return Err(RenameError("Method already has a self parameter".to_string()));
     }
+
+    let params = fn_def.params(sema.db);
     let first_param =
-        params.params().next().ok_or_else(|| RenameError("Method has no parameters".into()))?;
-    let mutable = match first_param.ty() {
-        Some(ast::Type::RefType(rt)) => rt.mut_token().is_some(),
-        _ => return Err(RenameError("Not renaming other types".to_string())),
+        params.first().ok_or_else(|| RenameError("Method has no parameters".into()))?;
+    let first_param_ty = first_param.ty();
+    let impl_ty = impl_block.target_ty(sema.db);
+    let (ty, self_param) = if impl_ty.remove_ref().is_some() {
+        // if the impl is a ref to the type we can just match the `&T` with self directly
+        (first_param_ty.clone(), "self")
+    } else {
+        first_param_ty.remove_ref().map_or((first_param_ty.clone(), "self"), |ty| {
+            (ty, if first_param_ty.is_mutable_reference() { "&mut self" } else { "&self" })
+        })
     };
 
+    if ty != impl_ty {
+        return Err(RenameError("Parameter type differs from impl block type".to_string()));
+    }
+
     let RangeInfo { range, info: refs } = find_all_refs(sema, position, None)
         .ok_or_else(|| RenameError("No reference found at position".to_string()))?;
 
-    let param_range = first_param.syntax().text_range();
     let (param_ref, usages): (Vec<Reference>, Vec<Reference>) = refs
         .into_iter()
         .partition(|reference| param_range.intersect(reference.file_range.range).is_some());
@@ -254,10 +277,7 @@ fn rename_to_self(
 
     edits.push(SourceFileEdit {
         file_id: position.file_id,
-        edit: TextEdit::replace(
-            param_range,
-            String::from(if mutable { "&mut self" } else { "&self" }),
-        ),
+        edit: TextEdit::replace(param_range, String::from(self_param)),
     });
 
     Ok(RangeInfo::new(range, SourceChange::from(edits)))
@@ -280,7 +300,11 @@ fn text_edit_from_self_param(
 
     let mut replacement_text = String::from(new_name);
     replacement_text.push_str(": ");
-    replacement_text.push_str(self_param.mut_token().map_or("&", |_| "&mut "));
+    match (self_param.amp_token(), self_param.mut_token()) {
+        (None, None) => (),
+        (Some(_), None) => replacement_text.push('&'),
+        (_, Some(_)) => replacement_text.push_str("&mut "),
+    };
     replacement_text.push_str(type_name.as_str());
 
     Some(TextEdit::replace(self_param.syntax().text_range(), replacement_text))
@@ -1082,6 +1106,95 @@ impl Foo {
 }
 "#,
         );
+        check(
+            "self",
+            r#"
+struct Foo { i: i32 }
+
+impl Foo {
+    fn f(foo<|>: Foo) -> i32 {
+        foo.i
+    }
+}
+"#,
+            r#"
+struct Foo { i: i32 }
+
+impl Foo {
+    fn f(self) -> i32 {
+        self.i
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn test_parameter_to_self_error_no_impl() {
+        check(
+            "self",
+            r#"
+struct Foo { i: i32 }
+
+fn f(foo<|>: &mut Foo) -> i32 {
+    foo.i
+}
+"#,
+            "error: No impl block found for function",
+        );
+        check(
+            "self",
+            r#"
+struct Foo { i: i32 }
+struct Bar;
+
+impl Bar {
+    fn f(foo<|>: &mut Foo) -> i32 {
+        foo.i
+    }
+}
+"#,
+            "error: Parameter type differs from impl block type",
+        );
+    }
+
+    #[test]
+    fn test_parameter_to_self_error_not_first() {
+        check(
+            "self",
+            r#"
+struct Foo { i: i32 }
+impl Foo {
+    fn f(x: (), foo<|>: &mut Foo) -> i32 {
+        foo.i
+    }
+}
+"#,
+            "error: Only the first parameter can be self",
+        );
+    }
+
+    #[test]
+    fn test_parameter_to_self_impl_ref() {
+        check(
+            "self",
+            r#"
+struct Foo { i: i32 }
+impl &Foo {
+    fn f(foo<|>: &Foo) -> i32 {
+        foo.i
+    }
+}
+"#,
+            r#"
+struct Foo { i: i32 }
+impl &Foo {
+    fn f(self) -> i32 {
+        self.i
+    }
+}
+"#,
+        );
     }
 
     #[test]
@@ -1110,6 +1223,31 @@ impl Foo {
     }
 
     #[test]
+    fn test_owned_self_to_parameter() {
+        check(
+            "foo",
+            r#"
+struct Foo { i: i32 }
+
+impl Foo {
+    fn f(<|>self) -> i32 {
+        self.i
+    }
+}
+"#,
+            r#"
+struct Foo { i: i32 }
+
+impl Foo {
+    fn f(foo: Foo) -> i32 {
+        foo.i
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
     fn test_self_in_path_to_parameter() {
         check(
             "foo",
diff --git a/crates/ide/src/syntax_highlighting.rs b/crates/ide/src/syntax_highlighting.rs
index 1ed77b40b..5150a970c 100644
--- a/crates/ide/src/syntax_highlighting.rs
+++ b/crates/ide/src/syntax_highlighting.rs
@@ -76,6 +76,7 @@ pub(crate) fn highlight(
     let mut current_macro_call: Option<ast::MacroCall> = None;
     let mut format_string_highlighter = FormatStringHighlighter::default();
     let mut macro_rules_highlighter = MacroRulesHighlighter::default();
+    let mut inside_attribute = false;
 
     // Walk all nodes, keeping track of whether we are inside a macro or not.
     // If in macro, expand it first and highlight the expanded code.
@@ -132,9 +133,12 @@ pub(crate) fn highlight(
             _ => (),
         }
 
-        // Check for Rust code in documentation
         match &event {
+            // Check for Rust code in documentation
             WalkEvent::Leave(NodeOrToken::Node(node)) => {
+                if ast::Attr::can_cast(node.kind()) {
+                    inside_attribute = false
+                }
                 if let Some((doctest, range_mapping, new_comments)) =
                     injection::extract_doc_comments(node)
                 {
@@ -146,6 +150,9 @@ pub(crate) fn highlight(
                     );
                 }
             }
+            WalkEvent::Enter(NodeOrToken::Node(node)) if ast::Attr::can_cast(node.kind()) => {
+                inside_attribute = true
+            }
             _ => (),
         }
 
@@ -188,12 +195,16 @@ pub(crate) fn highlight(
             }
         }
 
-        if let Some((highlight, binding_hash)) = highlight_element(
+        if let Some((mut highlight, binding_hash)) = highlight_element(
             &sema,
             &mut bindings_shadow_count,
             syntactic_name_ref_highlighting,
             element_to_highlight.clone(),
         ) {
+            if inside_attribute {
+                highlight = highlight | HighlightModifier::Attribute;
+            }
+
             if macro_rules_highlighter.highlight(element_to_highlight.clone()).is_none() {
                 stack.add(HighlightedRange { range, highlight, binding_hash });
             }
@@ -474,7 +485,9 @@ fn highlight_element(
 
         // Highlight references like the definitions they resolve to
         NAME_REF if element.ancestors().any(|it| it.kind() == ATTR) => {
-            Highlight::from(HighlightTag::Function) | HighlightModifier::Attribute
+            // even though we track whether we are in an attribute or not we still need this special case
+            // as otherwise we would emit unresolved references for name refs inside attributes
+            Highlight::from(HighlightTag::Function)
         }
         NAME_REF => {
             let name_ref = element.into_node().and_then(ast::NameRef::cast).unwrap();
diff --git a/crates/ide/src/syntax_highlighting/test_data/highlight_doctest.html b/crates/ide/src/syntax_highlighting/test_data/highlight_doctest.html
index 6be88f856..d79fa6dca 100644
--- a/crates/ide/src/syntax_highlighting/test_data/highlight_doctest.html
+++ b/crates/ide/src/syntax_highlighting/test_data/highlight_doctest.html
@@ -50,7 +50,7 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
     <span class="comment documentation">/// # Examples</span>
     <span class="comment documentation">///</span>
     <span class="comment documentation">/// ```</span>
-    <span class="comment documentation">/// #</span><span class="generic injected"> </span><span class="attribute injected">#</span><span class="attribute injected">!</span><span class="attribute injected">[</span><span class="function attribute injected">allow</span><span class="punctuation injected">(</span><span class="attribute injected">unused_mut</span><span class="punctuation injected">)</span><span class="attribute injected">]</span>
+    <span class="comment documentation">/// #</span><span class="generic injected"> </span><span class="attribute attribute injected">#</span><span class="attribute attribute injected">!</span><span class="attribute attribute injected">[</span><span class="function attribute injected">allow</span><span class="punctuation attribute injected">(</span><span class="attribute attribute injected">unused_mut</span><span class="punctuation attribute injected">)</span><span class="attribute attribute injected">]</span>
     <span class="comment documentation">/// </span><span class="keyword injected">let</span><span class="generic injected"> </span><span class="keyword injected">mut</span><span class="generic injected"> </span><span class="variable declaration injected mutable">foo</span><span class="punctuation injected">:</span><span class="generic injected"> </span><span class="struct injected">Foo</span><span class="generic injected"> </span><span class="operator injected">=</span><span class="generic injected"> </span><span class="struct injected">Foo</span><span class="operator injected">::</span><span class="function injected">new</span><span class="punctuation injected">(</span><span class="punctuation injected">)</span><span class="punctuation injected">;</span><span class="punctuation injected">
 </span>    <span class="comment documentation">/// ```</span>
     <span class="keyword">pub</span> <span class="keyword">const</span> <span class="keyword">fn</span> <span class="function declaration static">new</span><span class="punctuation">(</span><span class="punctuation">)</span> <span class="operator">-&gt;</span> <span class="struct">Foo</span> <span class="punctuation">{</span>
diff --git a/crates/ide/src/syntax_highlighting/test_data/highlight_unsafe.html b/crates/ide/src/syntax_highlighting/test_data/highlight_unsafe.html
index 4b6d6adc9..1d05b7713 100644
--- a/crates/ide/src/syntax_highlighting/test_data/highlight_unsafe.html
+++ b/crates/ide/src/syntax_highlighting/test_data/highlight_unsafe.html
@@ -54,7 +54,7 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 
 <span class="keyword">static</span> <span class="keyword">mut</span> <span class="static declaration mutable unsafe">global_mut</span><span class="punctuation">:</span> <span class="struct">TypeForStaticMut</span> <span class="operator">=</span> <span class="struct">TypeForStaticMut</span> <span class="punctuation">{</span> <span class="field">a</span><span class="punctuation">:</span> <span class="numeric_literal">0</span> <span class="punctuation">}</span><span class="punctuation">;</span>
 
-<span class="attribute">#</span><span class="attribute">[</span><span class="function attribute">repr</span><span class="punctuation">(</span><span class="attribute">packed</span><span class="punctuation">)</span><span class="attribute">]</span>
+<span class="attribute attribute">#</span><span class="attribute attribute">[</span><span class="function attribute">repr</span><span class="punctuation attribute">(</span><span class="attribute attribute">packed</span><span class="punctuation attribute">)</span><span class="attribute attribute">]</span>
 <span class="keyword">struct</span> <span class="struct declaration">Packed</span> <span class="punctuation">{</span>
     <span class="field declaration">a</span><span class="punctuation">:</span> <span class="builtin_type">u16</span><span class="punctuation">,</span>
 <span class="punctuation">}</span>
diff --git a/crates/ide/src/syntax_highlighting/test_data/highlighting.html b/crates/ide/src/syntax_highlighting/test_data/highlighting.html
index 6a10a9dcd..15fbf2ce3 100644
--- a/crates/ide/src/syntax_highlighting/test_data/highlighting.html
+++ b/crates/ide/src/syntax_highlighting/test_data/highlighting.html
@@ -40,18 +40,18 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 
 <span class="comment">// Needed for function consuming vs normal</span>
 <span class="keyword">pub</span> <span class="keyword">mod</span> <span class="module declaration">marker</span> <span class="punctuation">{</span>
-    <span class="attribute">#</span><span class="attribute">[</span><span class="function attribute">lang</span><span class="attribute"> </span><span class="operator">=</span><span class="attribute"> </span><span class="string_literal">"copy"</span><span class="attribute">]</span>
+    <span class="attribute attribute">#</span><span class="attribute attribute">[</span><span class="function attribute">lang</span><span class="attribute attribute"> </span><span class="operator attribute">=</span><span class="attribute attribute"> </span><span class="string_literal attribute">"copy"</span><span class="attribute attribute">]</span>
     <span class="keyword">pub</span> <span class="keyword">trait</span> <span class="trait declaration">Copy</span> <span class="punctuation">{</span><span class="punctuation">}</span>
 <span class="punctuation">}</span>
 
 <span class="keyword">pub</span> <span class="keyword">mod</span> <span class="module declaration">ops</span> <span class="punctuation">{</span>
-    <span class="attribute">#</span><span class="attribute">[</span><span class="function attribute">lang</span><span class="attribute"> </span><span class="operator">=</span><span class="attribute"> </span><span class="string_literal">"fn_once"</span><span class="attribute">]</span>
+    <span class="attribute attribute">#</span><span class="attribute attribute">[</span><span class="function attribute">lang</span><span class="attribute attribute"> </span><span class="operator attribute">=</span><span class="attribute attribute"> </span><span class="string_literal attribute">"fn_once"</span><span class="attribute attribute">]</span>
     <span class="keyword">pub</span> <span class="keyword">trait</span> <span class="trait declaration">FnOnce</span><span class="punctuation">&lt;</span><span class="type_param declaration">Args</span><span class="punctuation">&gt;</span> <span class="punctuation">{</span><span class="punctuation">}</span>
 
-    <span class="attribute">#</span><span class="attribute">[</span><span class="function attribute">lang</span><span class="attribute"> </span><span class="operator">=</span><span class="attribute"> </span><span class="string_literal">"fn_mut"</span><span class="attribute">]</span>
+    <span class="attribute attribute">#</span><span class="attribute attribute">[</span><span class="function attribute">lang</span><span class="attribute attribute"> </span><span class="operator attribute">=</span><span class="attribute attribute"> </span><span class="string_literal attribute">"fn_mut"</span><span class="attribute attribute">]</span>
     <span class="keyword">pub</span> <span class="keyword">trait</span> <span class="trait declaration">FnMut</span><span class="punctuation">&lt;</span><span class="type_param declaration">Args</span><span class="punctuation">&gt;</span><span class="punctuation">:</span> <span class="trait">FnOnce</span><span class="punctuation">&lt;</span><span class="type_param">Args</span><span class="punctuation">&gt;</span> <span class="punctuation">{</span><span class="punctuation">}</span>
 
-    <span class="attribute">#</span><span class="attribute">[</span><span class="function attribute">lang</span><span class="attribute"> </span><span class="operator">=</span><span class="attribute"> </span><span class="string_literal">"fn"</span><span class="attribute">]</span>
+    <span class="attribute attribute">#</span><span class="attribute attribute">[</span><span class="function attribute">lang</span><span class="attribute attribute"> </span><span class="operator attribute">=</span><span class="attribute attribute"> </span><span class="string_literal attribute">"fn"</span><span class="attribute attribute">]</span>
     <span class="keyword">pub</span> <span class="keyword">trait</span> <span class="trait declaration">Fn</span><span class="punctuation">&lt;</span><span class="type_param declaration">Args</span><span class="punctuation">&gt;</span><span class="punctuation">:</span> <span class="trait">FnMut</span><span class="punctuation">&lt;</span><span class="type_param">Args</span><span class="punctuation">&gt;</span> <span class="punctuation">{</span><span class="punctuation">}</span>
 <span class="punctuation">}</span>
 
@@ -85,7 +85,7 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
     <span class="punctuation">}</span>
 <span class="punctuation">}</span>
 
-<span class="attribute">#</span><span class="attribute">[</span><span class="function attribute">derive</span><span class="punctuation">(</span><span class="attribute">Copy</span><span class="punctuation">)</span><span class="attribute">]</span>
+<span class="attribute attribute">#</span><span class="attribute attribute">[</span><span class="function attribute">derive</span><span class="punctuation attribute">(</span><span class="attribute attribute">Copy</span><span class="punctuation attribute">)</span><span class="attribute attribute">]</span>
 <span class="keyword">struct</span> <span class="struct declaration">FooCopy</span> <span class="punctuation">{</span>
     <span class="field declaration">x</span><span class="punctuation">:</span> <span class="builtin_type">u32</span><span class="punctuation">,</span>
 <span class="punctuation">}</span>