23 files changed, 527 insertions, 221 deletions

diff --git a/crates/ra_ide/src/completion.rs b/crates/ra_ide/src/completion.rs
index a27e0fc15..93e53c921 100644
--- a/crates/ra_ide/src/completion.rs
+++ b/crates/ra_ide/src/completion.rs
@@ -16,11 +16,11 @@ mod complete_scope;
 mod complete_postfix;
 mod complete_macro_in_item_position;
 mod complete_trait_impl;
+#[cfg(test)]
+mod test_utils;
 
 use ra_ide_db::RootDatabase;
 
-#[cfg(test)]
-use crate::completion::completion_item::do_completion;
 use crate::{
     completion::{
         completion_context::CompletionContext,
diff --git a/crates/ra_ide/src/completion/complete_dot.rs b/crates/ra_ide/src/completion/complete_dot.rs
index d8f6f0d9d..81e5037aa 100644
--- a/crates/ra_ide/src/completion/complete_dot.rs
+++ b/crates/ra_ide/src/completion/complete_dot.rs
@@ -70,7 +70,7 @@ fn complete_methods(acc: &mut Completions, ctx: &CompletionContext, receiver: &T
 
 #[cfg(test)]
 mod tests {
-    use crate::completion::{do_completion, CompletionItem, CompletionKind};
+    use crate::completion::{test_utils::do_completion, CompletionItem, CompletionKind};
     use insta::assert_debug_snapshot;
 
     fn do_ref_completion(code: &str) -> Vec<CompletionItem> {
diff --git a/crates/ra_ide/src/completion/complete_fn_param.rs b/crates/ra_ide/src/completion/complete_fn_param.rs
index 502458706..9226ac055 100644
--- a/crates/ra_ide/src/completion/complete_fn_param.rs
+++ b/crates/ra_ide/src/completion/complete_fn_param.rs
@@ -52,7 +52,7 @@ pub(super) fn complete_fn_param(acc: &mut Completions, ctx: &CompletionContext)
 
 #[cfg(test)]
 mod tests {
-    use crate::completion::{do_completion, CompletionItem, CompletionKind};
+    use crate::completion::{test_utils::do_completion, CompletionItem, CompletionKind};
     use insta::assert_debug_snapshot;
 
     fn do_magic_completion(code: &str) -> Vec<CompletionItem> {
diff --git a/crates/ra_ide/src/completion/complete_keyword.rs b/crates/ra_ide/src/completion/complete_keyword.rs
index e1c0ffb1f..1e053ea4a 100644
--- a/crates/ra_ide/src/completion/complete_keyword.rs
+++ b/crates/ra_ide/src/completion/complete_keyword.rs
@@ -117,7 +117,7 @@ fn complete_return(
 
 #[cfg(test)]
 mod tests {
-    use crate::completion::{do_completion, CompletionItem, CompletionKind};
+    use crate::completion::{test_utils::do_completion, CompletionItem, CompletionKind};
     use insta::assert_debug_snapshot;
 
     fn do_keyword_completion(code: &str) -> Vec<CompletionItem> {
diff --git a/crates/ra_ide/src/completion/complete_macro_in_item_position.rs b/crates/ra_ide/src/completion/complete_macro_in_item_position.rs
index 1866d9e6c..270e96df0 100644
--- a/crates/ra_ide/src/completion/complete_macro_in_item_position.rs
+++ b/crates/ra_ide/src/completion/complete_macro_in_item_position.rs
@@ -15,9 +15,10 @@ pub(super) fn complete_macro_in_item_position(acc: &mut Completions, ctx: &Compl
 
 #[cfg(test)]
 mod tests {
-    use crate::completion::{do_completion, CompletionItem, CompletionKind};
     use insta::assert_debug_snapshot;
 
+    use crate::completion::{test_utils::do_completion, CompletionItem, CompletionKind};
+
     fn do_reference_completion(code: &str) -> Vec<CompletionItem> {
         do_completion(code, CompletionKind::Reference)
     }
diff --git a/crates/ra_ide/src/completion/complete_path.rs b/crates/ra_ide/src/completion/complete_path.rs
index 3c4a70561..d588ee364 100644
--- a/crates/ra_ide/src/completion/complete_path.rs
+++ b/crates/ra_ide/src/completion/complete_path.rs
@@ -103,7 +103,7 @@ pub(super) fn complete_path(acc: &mut Completions, ctx: &CompletionContext) {
 mod tests {
     use test_utils::covers;
 
-    use crate::completion::{do_completion, CompletionItem, CompletionKind};
+    use crate::completion::{test_utils::do_completion, CompletionItem, CompletionKind};
     use insta::assert_debug_snapshot;
 
     fn do_reference_completion(code: &str) -> Vec<CompletionItem> {
diff --git a/crates/ra_ide/src/completion/complete_pattern.rs b/crates/ra_ide/src/completion/complete_pattern.rs
index fa8aeceda..6a1a66ef1 100644
--- a/crates/ra_ide/src/completion/complete_pattern.rs
+++ b/crates/ra_ide/src/completion/complete_pattern.rs
@@ -27,7 +27,7 @@ pub(super) fn complete_pattern(acc: &mut Completions, ctx: &CompletionContext) {
 
 #[cfg(test)]
 mod tests {
-    use crate::completion::{do_completion, CompletionItem, CompletionKind};
+    use crate::completion::{test_utils::do_completion, CompletionItem, CompletionKind};
     use insta::assert_debug_snapshot;
 
     fn complete(code: &str) -> Vec<CompletionItem> {
diff --git a/crates/ra_ide/src/completion/complete_postfix.rs b/crates/ra_ide/src/completion/complete_postfix.rs
index 6d000548d..0ba382165 100644
--- a/crates/ra_ide/src/completion/complete_postfix.rs
+++ b/crates/ra_ide/src/completion/complete_postfix.rs
@@ -81,7 +81,7 @@ fn postfix_snippet(ctx: &CompletionContext, label: &str, detail: &str, snippet:
 mod tests {
     use insta::assert_debug_snapshot;
 
-    use crate::completion::{do_completion, CompletionItem, CompletionKind};
+    use crate::completion::{test_utils::do_completion, CompletionItem, CompletionKind};
 
     fn do_postfix_completion(code: &str) -> Vec<CompletionItem> {
         do_completion(code, CompletionKind::Postfix)
diff --git a/crates/ra_ide/src/completion/complete_record_literal.rs b/crates/ra_ide/src/completion/complete_record_literal.rs
index be6e4194f..83ed1d52c 100644
--- a/crates/ra_ide/src/completion/complete_record_literal.rs
+++ b/crates/ra_ide/src/completion/complete_record_literal.rs
@@ -18,7 +18,7 @@ pub(super) fn complete_record_literal(acc: &mut Completions, ctx: &CompletionCon
 
 #[cfg(test)]
 mod tests {
-    use crate::completion::{do_completion, CompletionItem, CompletionKind};
+    use crate::completion::{test_utils::do_completion, CompletionItem, CompletionKind};
     use insta::assert_debug_snapshot;
 
     fn complete(code: &str) -> Vec<CompletionItem> {
diff --git a/crates/ra_ide/src/completion/complete_record_pattern.rs b/crates/ra_ide/src/completion/complete_record_pattern.rs
index 687c57d3e..962376428 100644
--- a/crates/ra_ide/src/completion/complete_record_pattern.rs
+++ b/crates/ra_ide/src/completion/complete_record_pattern.rs
@@ -17,7 +17,7 @@ pub(super) fn complete_record_pattern(acc: &mut Completions, ctx: &CompletionCon
 
 #[cfg(test)]
 mod tests {
-    use crate::completion::{do_completion, CompletionItem, CompletionKind};
+    use crate::completion::{test_utils::do_completion, CompletionItem, CompletionKind};
     use insta::assert_debug_snapshot;
 
     fn complete(code: &str) -> Vec<CompletionItem> {
diff --git a/crates/ra_ide/src/completion/complete_scope.rs b/crates/ra_ide/src/completion/complete_scope.rs
index eb3c8cf1b..bd4adf23a 100644
--- a/crates/ra_ide/src/completion/complete_scope.rs
+++ b/crates/ra_ide/src/completion/complete_scope.rs
@@ -14,10 +14,10 @@ pub(super) fn complete_scope(acc: &mut Completions, ctx: &CompletionContext) {
 mod tests {
     use insta::assert_debug_snapshot;
 
-    use crate::completion::{do_completion, CompletionItem, CompletionKind};
+    use crate::completion::{test_utils::do_completion, CompletionItem, CompletionKind};
 
-    fn do_reference_completion(code: &str) -> Vec<CompletionItem> {
-        do_completion(code, CompletionKind::Reference)
+    fn do_reference_completion(ra_fixture: &str) -> Vec<CompletionItem> {
+        do_completion(ra_fixture, CompletionKind::Reference)
     }
 
     #[test]
diff --git a/crates/ra_ide/src/completion/complete_snippet.rs b/crates/ra_ide/src/completion/complete_snippet.rs
index 731b4fd82..f731e9b9a 100644
--- a/crates/ra_ide/src/completion/complete_snippet.rs
+++ b/crates/ra_ide/src/completion/complete_snippet.rs
@@ -42,7 +42,7 @@ fn ${1:feature}() {
 
 #[cfg(test)]
 mod tests {
-    use crate::completion::{do_completion, CompletionItem, CompletionKind};
+    use crate::completion::{test_utils::do_completion, CompletionItem, CompletionKind};
     use insta::assert_debug_snapshot;
 
     fn do_snippet_completion(code: &str) -> Vec<CompletionItem> {
diff --git a/crates/ra_ide/src/completion/complete_trait_impl.rs b/crates/ra_ide/src/completion/complete_trait_impl.rs
index 2bf654a57..7fefa2c7a 100644
--- a/crates/ra_ide/src/completion/complete_trait_impl.rs
+++ b/crates/ra_ide/src/completion/complete_trait_impl.rs
@@ -217,7 +217,7 @@ fn make_const_compl_syntax(const_: &ast::ConstDef) -> String {
 
 #[cfg(test)]
 mod tests {
-    use crate::completion::{do_completion, CompletionItem, CompletionKind};
+    use crate::completion::{test_utils::do_completion, CompletionItem, CompletionKind};
     use insta::assert_debug_snapshot;
 
     fn complete(code: &str) -> Vec<CompletionItem> {
diff --git a/crates/ra_ide/src/completion/completion_item.rs b/crates/ra_ide/src/completion/completion_item.rs
index 1d14e9636..ef0eb43b2 100644
--- a/crates/ra_ide/src/completion/completion_item.rs
+++ b/crates/ra_ide/src/completion/completion_item.rs
@@ -13,7 +13,7 @@ pub struct CompletionItem {
     /// Used only internally in tests, to check only specific kind of
     /// completion (postfix, keyword, reference, etc).
     #[allow(unused)]
-    completion_kind: CompletionKind,
+    pub(crate) completion_kind: CompletionKind,
     /// Label in the completion pop up which identifies completion.
     label: String,
     /// Range of identifier that is being completed.
@@ -318,24 +318,3 @@ impl Into<Vec<CompletionItem>> for Completions {
         self.buf
     }
 }
-
-#[cfg(test)]
-pub(crate) fn do_completion(code: &str, kind: CompletionKind) -> Vec<CompletionItem> {
-    use crate::{
-        completion::{completions, CompletionOptions},
-        mock_analysis::{analysis_and_position, single_file_with_position},
-    };
-
-    let (analysis, position) = if code.contains("//-") {
-        analysis_and_position(code)
-    } else {
-        single_file_with_position(code)
-    };
-    let options = CompletionOptions::default();
-    let completions = completions(&analysis.db, position, &options).unwrap();
-    let completion_items: Vec<CompletionItem> = completions.into();
-    let mut kind_completions: Vec<CompletionItem> =
-        completion_items.into_iter().filter(|c| c.completion_kind == kind).collect();
-    kind_completions.sort_by_key(|c| c.label.clone());
-    kind_completions
-}
diff --git a/crates/ra_ide/src/completion/presentation.rs b/crates/ra_ide/src/completion/presentation.rs
index 3dc56e4a3..5213def20 100644
--- a/crates/ra_ide/src/completion/presentation.rs
+++ b/crates/ra_ide/src/completion/presentation.rs
@@ -307,12 +307,22 @@ mod tests {
     use insta::assert_debug_snapshot;
     use test_utils::covers;
 
-    use crate::completion::{do_completion, CompletionItem, CompletionKind};
+    use crate::completion::{
+        test_utils::{do_completion, do_completion_with_options},
+        CompletionItem, CompletionKind, CompletionOptions,
+    };
 
     fn do_reference_completion(ra_fixture: &str) -> Vec<CompletionItem> {
         do_completion(ra_fixture, CompletionKind::Reference)
     }
 
+    fn do_reference_completion_with_options(
+        ra_fixture: &str,
+        options: CompletionOptions,
+    ) -> Vec<CompletionItem> {
+        do_completion_with_options(ra_fixture, CompletionKind::Reference, &options)
+    }
+
     #[test]
     fn enum_detail_includes_names_for_record() {
         assert_debug_snapshot!(
@@ -533,7 +543,7 @@ mod tests {
     }
 
     #[test]
-    fn parens_for_method_call() {
+    fn arg_snippets_for_method_call() {
         assert_debug_snapshot!(
             do_reference_completion(
                 r"
@@ -563,6 +573,40 @@ mod tests {
     }
 
     #[test]
+    fn no_arg_snippets_for_method_call() {
+        assert_debug_snapshot!(
+            do_reference_completion_with_options(
+                r"
+                struct S {}
+                impl S {
+                    fn foo(&self, x: i32) {}
+                }
+                fn bar(s: &S) {
+                    s.f<|>
+                }
+                ",
+                CompletionOptions {
+                    add_call_argument_snippets: false,
+                    .. Default::default()
+                }
+            ),
+            @r###"
+        [
+            CompletionItem {
+                label: "foo(…)",
+                source_range: [171; 172),
+                delete: [171; 172),
+                insert: "foo($0)",
+                kind: Method,
+                lookup: "foo",
+                detail: "fn foo(&self, x: i32)",
+            },
+        ]
+        "###
+        )
+    }
+
+    #[test]
     fn dont_render_function_parens_in_use_item() {
         assert_debug_snapshot!(
             do_reference_completion(
diff --git a/crates/ra_ide/src/completion/test_utils.rs b/crates/ra_ide/src/completion/test_utils.rs
new file mode 100644
index 000000000..136857315
--- /dev/null
+++ b/crates/ra_ide/src/completion/test_utils.rs
@@ -0,0 +1,29 @@
+//! Runs completion for testing purposes.
+
+use crate::{
+    completion::{completion_item::CompletionKind, CompletionOptions},
+    mock_analysis::{analysis_and_position, single_file_with_position},
+    CompletionItem,
+};
+
+pub(crate) fn do_completion(code: &str, kind: CompletionKind) -> Vec<CompletionItem> {
+    do_completion_with_options(code, kind, &CompletionOptions::default())
+}
+
+pub(crate) fn do_completion_with_options(
+    code: &str,
+    kind: CompletionKind,
+    options: &CompletionOptions,
+) -> Vec<CompletionItem> {
+    let (analysis, position) = if code.contains("//-") {
+        analysis_and_position(code)
+    } else {
+        single_file_with_position(code)
+    };
+    let completions = analysis.completions(position, options).unwrap().unwrap();
+    let completion_items: Vec<CompletionItem> = completions.into();
+    let mut kind_completions: Vec<CompletionItem> =
+        completion_items.into_iter().filter(|c| c.completion_kind == kind).collect();
+    kind_completions.sort_by_key(|c| c.label().to_owned());
+    kind_completions
+}
diff --git a/crates/ra_ide/src/hover.rs b/crates/ra_ide/src/hover.rs
index 25e038a55..0bbba4855 100644
--- a/crates/ra_ide/src/hover.rs
+++ b/crates/ra_ide/src/hover.rs
@@ -833,19 +833,34 @@ fn func(foo: i32) { if true { <|>foo; }; }
     }
 
     #[test]
+    fn test_hover_through_assert_macro() {
+        let hover_on = check_hover_result(
+            r#"
+            //- /lib.rs
+            #[rustc_builtin_macro]
+            macro_rules! assert {}
+
+            fn bar() -> bool { true }
+            fn foo() {
+                assert!(ba<|>r());
+            }
+            "#,
+            &["fn bar() -> bool"],
+        );
+
+        assert_eq!(hover_on, "bar");
+    }
+
+    #[test]
     fn test_hover_through_literal_string_in_builtin_macro() {
         check_hover_no_result(
             r#"
             //- /lib.rs
             #[rustc_builtin_macro]
-            macro_rules! assert {
-                ($cond:expr) => {{ /* compiler built-in */ }};
-                ($cond:expr,) => {{ /* compiler built-in */ }};
-                ($cond:expr, $($arg:tt)+) => {{ /* compiler built-in */ }};
-            }
+            macro_rules! format {}
 
             fn foo() {
-                assert!("hel<|>lo");
+                format!("hel<|>lo {}", 0);
             }
             "#,
         );
diff --git a/crates/ra_ide/src/lib.rs b/crates/ra_ide/src/lib.rs
index a3acfd225..922e4caa8 100644
--- a/crates/ra_ide/src/lib.rs
+++ b/crates/ra_ide/src/lib.rs
@@ -212,6 +212,7 @@ impl Analysis {
             None,
             cfg_options,
             Env::default(),
+            Default::default(),
         );
         change.add_file(source_root, file_id, "main.rs".into(), Arc::new(text));
         change.set_crate_graph(crate_graph);
diff --git a/crates/ra_ide/src/mock_analysis.rs b/crates/ra_ide/src/mock_analysis.rs
index 90f84b052..25816cf6f 100644
--- a/crates/ra_ide/src/mock_analysis.rs
+++ b/crates/ra_ide/src/mock_analysis.rs
@@ -102,6 +102,7 @@ impl MockAnalysis {
                     None,
                     cfg_options,
                     Env::default(),
+                    Default::default(),
                 ));
             } else if path.ends_with("/lib.rs") {
                 let crate_name = path.parent().unwrap().file_name().unwrap();
@@ -111,6 +112,7 @@ impl MockAnalysis {
                     Some(crate_name.to_owned()),
                     cfg_options,
                     Env::default(),
+                    Default::default(),
                 );
                 if let Some(root_crate) = root_crate {
                     crate_graph
diff --git a/crates/ra_ide/src/parent_module.rs b/crates/ra_ide/src/parent_module.rs
index b73cefd97..76d130b9b 100644
--- a/crates/ra_ide/src/parent_module.rs
+++ b/crates/ra_ide/src/parent_module.rs
@@ -136,6 +136,7 @@ mod tests {
             None,
             CfgOptions::default(),
             Env::default(),
+            Default::default(),
         );
         let mut change = AnalysisChange::new();
         change.set_crate_graph(crate_graph);
diff --git a/crates/ra_ide/src/references/rename.rs b/crates/ra_ide/src/references/rename.rs
index 5b4bcf434..7d1190af9 100644
--- a/crates/ra_ide/src/references/rename.rs
+++ b/crates/ra_ide/src/references/rename.rs
@@ -9,7 +9,8 @@ use ra_syntax::{
 use ra_text_edit::TextEdit;
 
 use crate::{
-    FileId, FilePosition, FileSystemEdit, RangeInfo, SourceChange, SourceFileEdit, TextRange,
+    FilePosition, FileSystemEdit, RangeInfo, Reference, ReferenceKind, SourceChange,
+    SourceFileEdit, TextRange,
 };
 
 use super::find_all_refs;
@@ -46,12 +47,29 @@ fn find_name_and_module_at_offset(
     Some((ast_name, ast_module))
 }
 
-fn source_edit_from_file_id_range(
-    file_id: FileId,
-    range: TextRange,
-    new_name: &str,
-) -> SourceFileEdit {
-    SourceFileEdit { file_id, edit: TextEdit::replace(range, new_name.into()) }
+fn source_edit_from_reference(reference: Reference, new_name: &str) -> SourceFileEdit {
+    let mut replacement_text = String::new();
+    let file_id = reference.file_range.file_id;
+    let range = match reference.kind {
+        ReferenceKind::StructFieldShorthandForField => {
+            replacement_text.push_str(new_name);
+            replacement_text.push_str(": ");
+            TextRange::from_to(
+                reference.file_range.range.start(),
+                reference.file_range.range.start(),
+            )
+        }
+        ReferenceKind::StructFieldShorthandForLocal => {
+            replacement_text.push_str(": ");
+            replacement_text.push_str(new_name);
+            TextRange::from_to(reference.file_range.range.end(), reference.file_range.range.end())
+        }
+        _ => {
+            replacement_text.push_str(new_name);
+            reference.file_range.range
+        }
+    };
+    SourceFileEdit { file_id, edit: TextEdit::replace(range, replacement_text) }
 }
 
 fn rename_mod(
@@ -99,13 +117,10 @@ fn rename_mod(
     source_file_edits.push(edit);
 
     if let Some(RangeInfo { range: _, info: refs }) = find_all_refs(sema.db, position, None) {
-        let ref_edits = refs.references.into_iter().map(|reference| {
-            source_edit_from_file_id_range(
-                reference.file_range.file_id,
-                reference.file_range.range,
-                new_name,
-            )
-        });
+        let ref_edits = refs
+            .references
+            .into_iter()
+            .map(|reference| source_edit_from_reference(reference, new_name));
         source_file_edits.extend(ref_edits);
     }
 
@@ -121,13 +136,7 @@ fn rename_reference(
 
     let edit = refs
         .into_iter()
-        .map(|reference| {
-            source_edit_from_file_id_range(
-                reference.file_range.file_id,
-                reference.file_range.range,
-                new_name,
-            )
-        })
+        .map(|reference| source_edit_from_reference(reference, new_name))
         .collect::<Vec<_>>();
 
     if edit.is_empty() {
@@ -286,6 +295,163 @@ mod tests {
     }
 
     #[test]
+    fn test_rename_struct_field() {
+        test_rename(
+            r#"
+    struct Foo {
+        i<|>: i32,
+    }
+
+    impl Foo {
+        fn new(i: i32) -> Self {
+            Self { i: i }
+        }
+    }
+    "#,
+            "j",
+            r#"
+    struct Foo {
+        j: i32,
+    }
+
+    impl Foo {
+        fn new(i: i32) -> Self {
+            Self { j: i }
+        }
+    }
+    "#,
+        );
+    }
+
+    #[test]
+    fn test_rename_struct_field_for_shorthand() {
+        test_rename(
+            r#"
+    struct Foo {
+        i<|>: i32,
+    }
+
+    impl Foo {
+        fn new(i: i32) -> Self {
+            Self { i }
+        }
+    }
+    "#,
+            "j",
+            r#"
+    struct Foo {
+        j: i32,
+    }
+
+    impl Foo {
+        fn new(i: i32) -> Self {
+            Self { j: i }
+        }
+    }
+    "#,
+        );
+    }
+
+    #[test]
+    fn test_rename_local_for_field_shorthand() {
+        test_rename(
+            r#"
+    struct Foo {
+        i: i32,
+    }
+
+    impl Foo {
+        fn new(i<|>: i32) -> Self {
+            Self { i }
+        }
+    }
+    "#,
+            "j",
+            r#"
+    struct Foo {
+        i: i32,
+    }
+
+    impl Foo {
+        fn new(j: i32) -> Self {
+            Self { i: j }
+        }
+    }
+    "#,
+        );
+    }
+
+    #[test]
+    fn test_field_shorthand_correct_struct() {
+        test_rename(
+            r#"
+    struct Foo {
+        i<|>: i32,
+    }
+
+    struct Bar {
+        i: i32,
+    }
+
+    impl Bar {
+        fn new(i: i32) -> Self {
+            Self { i }
+        }
+    }
+    "#,
+            "j",
+            r#"
+    struct Foo {
+        j: i32,
+    }
+
+    struct Bar {
+        i: i32,
+    }
+
+    impl Bar {
+        fn new(i: i32) -> Self {
+            Self { i }
+        }
+    }
+    "#,
+        );
+    }
+
+    #[test]
+    fn test_shadow_local_for_struct_shorthand() {
+        test_rename(
+            r#"
+    struct Foo {
+        i: i32,
+    }
+
+    fn baz(i<|>: i32) -> Self {
+         let x = Foo { i };
+         {
+             let i = 0;
+             Foo { i }
+         }
+     }
+    "#,
+            "j",
+            r#"
+    struct Foo {
+        i: i32,
+    }
+
+    fn baz(j: i32) -> Self {
+         let x = Foo { i: j };
+         {
+             let i = 0;
+             Foo { i }
+         }
+     }
+    "#,
+        );
+    }
+
+    #[test]
     fn test_rename_mod() {
         let (analysis, position) = analysis_and_position(
             "
diff --git a/crates/ra_ide/src/typing.rs b/crates/ra_ide/src/typing.rs
index 7f1b9150f..53c65f8bc 100644
--- a/crates/ra_ide/src/typing.rs
+++ b/crates/ra_ide/src/typing.rs
@@ -13,77 +13,21 @@
 //! Language server executes such typing assists synchronously. That is, they
 //! block user's typing and should be pretty fast for this reason!
 
+mod on_enter;
+
 use ra_db::{FilePosition, SourceDatabase};
 use ra_fmt::leading_indent;
 use ra_ide_db::RootDatabase;
 use ra_syntax::{
     algo::find_node_at_offset,
     ast::{self, AstToken},
-    AstNode, SmolStr, SourceFile,
-    SyntaxKind::*,
-    SyntaxToken, TextRange, TextUnit, TokenAtOffset,
+    AstNode, SourceFile, TextRange, TextUnit,
 };
 use ra_text_edit::TextEdit;
 
-use crate::{source_change::SingleFileChange, SourceChange, SourceFileEdit};
-
-pub(crate) fn on_enter(db: &RootDatabase, position: FilePosition) -> Option<SourceChange> {
-    let parse = db.parse(position.file_id);
-    let file = parse.tree();
-    let comment = file
-        .syntax()
-        .token_at_offset(position.offset)
-        .left_biased()
-        .and_then(ast::Comment::cast)?;
-
-    if comment.kind().shape.is_block() {
-        return None;
-    }
-
-    let prefix = comment.prefix();
-    let comment_range = comment.syntax().text_range();
-    if position.offset < comment_range.start() + TextUnit::of_str(prefix) {
-        return None;
-    }
-
-    // Continuing non-doc line comments (like this one :) ) is annoying
-    if prefix == "//" && comment_range.end() == position.offset {
-        return None;
-    }
-
-    let indent = node_indent(&file, comment.syntax())?;
-    let inserted = format!("\n{}{} ", indent, prefix);
-    let cursor_position = position.offset + TextUnit::of_str(&inserted);
-    let edit = TextEdit::insert(position.offset, inserted);
+use crate::{source_change::SingleFileChange, SourceChange};
 
-    Some(
-        SourceChange::source_file_edit(
-            "on enter",
-            SourceFileEdit { edit, file_id: position.file_id },
-        )
-        .with_cursor(FilePosition { offset: cursor_position, file_id: position.file_id }),
-    )
-}
-
-fn node_indent(file: &SourceFile, token: &SyntaxToken) -> Option<SmolStr> {
-    let ws = match file.syntax().token_at_offset(token.text_range().start()) {
-        TokenAtOffset::Between(l, r) => {
-            assert!(r == *token);
-            l
-        }
-        TokenAtOffset::Single(n) => {
-            assert!(n == *token);
-            return Some("".into());
-        }
-        TokenAtOffset::None => unreachable!(),
-    };
-    if ws.kind() != WHITESPACE {
-        return None;
-    }
-    let text = ws.text();
-    let pos = text.rfind('\n').map(|it| it + 1).unwrap_or(0);
-    Some(text[pos..].into())
-}
+pub(crate) use on_enter::on_enter;
 
 pub(crate) const TRIGGER_CHARS: &str = ".=>";
 
@@ -196,102 +140,10 @@ fn on_arrow_typed(file: &SourceFile, offset: TextUnit) -> Option<SingleFileChang
 
 #[cfg(test)]
 mod tests {
-    use test_utils::{add_cursor, assert_eq_text, extract_offset};
-
-    use crate::mock_analysis::single_file;
+    use test_utils::{assert_eq_text, extract_offset};
 
     use super::*;
 
-    #[test]
-    fn test_on_enter() {
-        fn apply_on_enter(before: &str) -> Option<String> {
-            let (offset, before) = extract_offset(before);
-            let (analysis, file_id) = single_file(&before);
-            let result = analysis.on_enter(FilePosition { offset, file_id }).unwrap()?;
-
-            assert_eq!(result.source_file_edits.len(), 1);
-            let actual = result.source_file_edits[0].edit.apply(&before);
-            let actual = add_cursor(&actual, result.cursor_position.unwrap().offset);
-            Some(actual)
-        }
-
-        fn do_check(before: &str, after: &str) {
-            let actual = apply_on_enter(before).unwrap();
-            assert_eq_text!(after, &actual);
-        }
-
-        fn do_check_noop(text: &str) {
-            assert!(apply_on_enter(text).is_none())
-        }
-
-        do_check(
-            r"
-/// Some docs<|>
-fn foo() {
-}
-",
-            r"
-/// Some docs
-/// <|>
-fn foo() {
-}
-",
-        );
-        do_check(
-            r"
-impl S {
-    /// Some<|> docs.
-    fn foo() {}
-}
-",
-            r"
-impl S {
-    /// Some
-    /// <|> docs.
-    fn foo() {}
-}
-",
-        );
-        do_check(
-            r"
-fn main() {
-    // Fix<|> me
-    let x = 1 + 1;
-}
-",
-            r"
-fn main() {
-    // Fix
-    // <|> me
-    let x = 1 + 1;
-}
-",
-        );
-        do_check(
-            r"
-///<|> Some docs
-fn foo() {
-}
-",
-            r"
-///
-/// <|> Some docs
-fn foo() {
-}
-",
-        );
-        do_check_noop(
-            r"
-fn main() {
-    // Fix me<|>
-    let x = 1 + 1;
-}
-",
-        );
-
-        do_check_noop(r"<|>//! docz");
-    }
-
     fn do_type_char(char_typed: char, before: &str) -> Option<(String, SingleFileChange)> {
         let (offset, before) = extract_offset(before);
         let edit = TextEdit::insert(offset, char_typed.to_string());
diff --git a/crates/ra_ide/src/typing/on_enter.rs b/crates/ra_ide/src/typing/on_enter.rs
new file mode 100644
index 000000000..6bcf2d72b
--- /dev/null
+++ b/crates/ra_ide/src/typing/on_enter.rs
@@ -0,0 +1,216 @@
+//! Handles the `Enter` key press. At the momently, this only continues
+//! comments, but should handle indent some time in the future as well.
+
+use ra_db::{FilePosition, SourceDatabase};
+use ra_ide_db::RootDatabase;
+use ra_syntax::{
+    ast::{self, AstToken},
+    AstNode, SmolStr, SourceFile,
+    SyntaxKind::*,
+    SyntaxToken, TextUnit, TokenAtOffset,
+};
+use ra_text_edit::TextEdit;
+
+use crate::{SourceChange, SourceFileEdit};
+
+pub(crate) fn on_enter(db: &RootDatabase, position: FilePosition) -> Option<SourceChange> {
+    let parse = db.parse(position.file_id);
+    let file = parse.tree();
+    let comment = file
+        .syntax()
+        .token_at_offset(position.offset)
+        .left_biased()
+        .and_then(ast::Comment::cast)?;
+
+    if comment.kind().shape.is_block() {
+        return None;
+    }
+
+    let prefix = comment.prefix();
+    let comment_range = comment.syntax().text_range();
+    if position.offset < comment_range.start() + TextUnit::of_str(prefix) {
+        return None;
+    }
+
+    // Continuing single-line non-doc comments (like this one :) ) is annoying
+    if prefix == "//" && comment_range.end() == position.offset && !followed_by_comment(&comment) {
+        return None;
+    }
+
+    let indent = node_indent(&file, comment.syntax())?;
+    let inserted = format!("\n{}{} ", indent, prefix);
+    let cursor_position = position.offset + TextUnit::of_str(&inserted);
+    let edit = TextEdit::insert(position.offset, inserted);
+
+    Some(
+        SourceChange::source_file_edit(
+            "on enter",
+            SourceFileEdit { edit, file_id: position.file_id },
+        )
+        .with_cursor(FilePosition { offset: cursor_position, file_id: position.file_id }),
+    )
+}
+
+fn followed_by_comment(comment: &ast::Comment) -> bool {
+    let ws = match comment.syntax().next_token().and_then(ast::Whitespace::cast) {
+        Some(it) => it,
+        None => return false,
+    };
+    if ws.spans_multiple_lines() {
+        return false;
+    }
+    ws.syntax().next_token().and_then(ast::Comment::cast).is_some()
+}
+
+fn node_indent(file: &SourceFile, token: &SyntaxToken) -> Option<SmolStr> {
+    let ws = match file.syntax().token_at_offset(token.text_range().start()) {
+        TokenAtOffset::Between(l, r) => {
+            assert!(r == *token);
+            l
+        }
+        TokenAtOffset::Single(n) => {
+            assert!(n == *token);
+            return Some("".into());
+        }
+        TokenAtOffset::None => unreachable!(),
+    };
+    if ws.kind() != WHITESPACE {
+        return None;
+    }
+    let text = ws.text();
+    let pos = text.rfind('\n').map(|it| it + 1).unwrap_or(0);
+    Some(text[pos..].into())
+}
+
+#[cfg(test)]
+mod tests {
+    use test_utils::{add_cursor, assert_eq_text, extract_offset};
+
+    use crate::mock_analysis::single_file;
+
+    use super::*;
+
+    fn apply_on_enter(before: &str) -> Option<String> {
+        let (offset, before) = extract_offset(before);
+        let (analysis, file_id) = single_file(&before);
+        let result = analysis.on_enter(FilePosition { offset, file_id }).unwrap()?;
+
+        assert_eq!(result.source_file_edits.len(), 1);
+        let actual = result.source_file_edits[0].edit.apply(&before);
+        let actual = add_cursor(&actual, result.cursor_position.unwrap().offset);
+        Some(actual)
+    }
+
+    fn do_check(ra_fixture_before: &str, ra_fixture_after: &str) {
+        let actual = apply_on_enter(ra_fixture_before).unwrap();
+        assert_eq_text!(ra_fixture_after, &actual);
+    }
+
+    fn do_check_noop(ra_fixture_text: &str) {
+        assert!(apply_on_enter(ra_fixture_text).is_none())
+    }
+
+    #[test]
+    fn continues_doc_comment() {
+        do_check(
+            r"
+/// Some docs<|>
+fn foo() {
+}
+",
+            r"
+/// Some docs
+/// <|>
+fn foo() {
+}
+",
+        );
+
+        do_check(
+            r"
+impl S {
+    /// Some<|> docs.
+    fn foo() {}
+}
+",
+            r"
+impl S {
+    /// Some
+    /// <|> docs.
+    fn foo() {}
+}
+",
+        );
+
+        do_check(
+            r"
+///<|> Some docs
+fn foo() {
+}
+",
+            r"
+///
+/// <|> Some docs
+fn foo() {
+}
+",
+        );
+    }
+
+    #[test]
+    fn does_not_continue_before_doc_comment() {
+        do_check_noop(r"<|>//! docz");
+    }
+
+    #[test]
+    fn continues_code_comment_in_the_middle_of_line() {
+        do_check(
+            r"
+fn main() {
+    // Fix<|> me
+    let x = 1 + 1;
+}
+",
+            r"
+fn main() {
+    // Fix
+    // <|> me
+    let x = 1 + 1;
+}
+",
+        );
+    }
+
+    #[test]
+    fn continues_code_comment_in_the_middle_several_lines() {
+        do_check(
+            r"
+fn main() {
+    // Fix<|>
+    // me
+    let x = 1 + 1;
+}
+",
+            r"
+fn main() {
+    // Fix
+    // <|>
+    // me
+    let x = 1 + 1;
+}
+",
+        );
+    }
+
+    #[test]
+    fn does_not_continue_end_of_code_comment() {
+        do_check_noop(
+            r"
+fn main() {
+    // Fix me<|>
+    let x = 1 + 1;
+}
+",
+        );
+    }
+}