6 files changed, 158 insertions, 7 deletions

diff --git a/crates/ra_ide_db/src/defs.rs b/crates/ra_ide_db/src/defs.rs
index 7cd2384e9..f990e3bb9 100644
--- a/crates/ra_ide_db/src/defs.rs
+++ b/crates/ra_ide_db/src/defs.rs
@@ -6,7 +6,7 @@
 // FIXME: this badly needs rename/rewrite (matklad, 2020-02-06).
 
 use hir::{
-    Field, HasVisibility, ImplDef, Local, MacroDef, Module, ModuleDef, Name, PathResolution,
+    Adt, Field, HasVisibility, ImplDef, Local, MacroDef, Module, ModuleDef, Name, PathResolution,
     Semantics, TypeParam, Visibility,
 };
 use ra_prof::profile;
@@ -47,7 +47,13 @@ impl Definition {
         match self {
             Definition::Macro(_) => None,
             Definition::Field(sf) => Some(sf.visibility(db)),
-            Definition::ModuleDef(def) => module?.visibility_of(db, def),
+            Definition::ModuleDef(def) => match def {
+                ModuleDef::EnumVariant(id) => {
+                    let parent = id.parent_enum(db);
+                    module?.visibility_of(db, &ModuleDef::Adt(Adt::Enum(parent)))
+                }
+                _ => module?.visibility_of(db, def),
+            },
             Definition::SelfType(_) => None,
             Definition::Local(_) => None,
             Definition::TypeParam(_) => None,
@@ -119,6 +125,16 @@ fn classify_name_inner(sema: &Semantics<RootDatabase>, name: &ast::Name) -> Opti
 
     match_ast! {
         match parent {
+            ast::Alias(it) => {
+                tested_by!(goto_def_for_use_alias; force);
+                let use_tree = it.syntax().parent().and_then(ast::UseTree::cast)?;
+                let path = use_tree.path()?;
+                let path_segment = path.segment()?;
+                let name_ref = path_segment.name_ref()?;
+                let name_ref_class = classify_name_ref(sema, &name_ref)?;
+
+                Some(name_ref_class.definition())
+            },
             ast::BindPat(it) => {
                 let local = sema.to_def(&it)?;
                 Some(Definition::Local(local))
diff --git a/crates/ra_ide_db/src/lib.rs b/crates/ra_ide_db/src/lib.rs
index e6f2d36e9..52fcd7b6f 100644
--- a/crates/ra_ide_db/src/lib.rs
+++ b/crates/ra_ide_db/src/lib.rs
@@ -10,6 +10,7 @@ pub mod change;
 pub mod defs;
 pub mod search;
 pub mod imports_locator;
+pub mod source_change;
 mod wasm_shims;
 
 use std::sync::Arc;
diff --git a/crates/ra_ide_db/src/line_index.rs b/crates/ra_ide_db/src/line_index.rs
index 212cb7b5b..c7c744fce 100644
--- a/crates/ra_ide_db/src/line_index.rs
+++ b/crates/ra_ide_db/src/line_index.rs
@@ -31,9 +31,19 @@ pub(crate) struct Utf16Char {
 }
 
 impl Utf16Char {
+    /// Returns the length in 8-bit UTF-8 code units.
     fn len(&self) -> TextSize {
         self.end - self.start
     }
+
+    /// Returns the length in 16-bit UTF-16 code units.
+    fn len_utf16(&self) -> usize {
+        if self.len() == TextSize::from(4) {
+            2
+        } else {
+            1
+        }
+    }
 }
 
 impl LineIndex {
@@ -110,7 +120,7 @@ impl LineIndex {
         if let Some(utf16_chars) = self.utf16_lines.get(&line) {
             for c in utf16_chars {
                 if c.end <= col {
-                    res -= usize::from(c.len()) - 1;
+                    res -= usize::from(c.len()) - c.len_utf16();
                 } else {
                     // From here on, all utf16 characters come *after* the character we are mapping,
                     // so we don't need to take them into account
@@ -125,7 +135,7 @@ impl LineIndex {
         if let Some(utf16_chars) = self.utf16_lines.get(&line) {
             for c in utf16_chars {
                 if col > u32::from(c.start) {
-                    col += u32::from(c.len()) - 1;
+                    col += u32::from(c.len()) - c.len_utf16() as u32;
                 } else {
                     // From here on, all utf16 characters come *after* the character we are mapping,
                     // so we don't need to take them into account
@@ -204,6 +214,9 @@ const C: char = 'メ';
 
         // UTF-16 to UTF-8
         assert_eq!(col_index.utf16_to_utf8_col(1, 19), TextSize::from(21));
+
+        let col_index = LineIndex::new("a𐐏b");
+        assert_eq!(col_index.utf16_to_utf8_col(0, 3), TextSize::from(5));
     }
 
     #[test]
diff --git a/crates/ra_ide_db/src/line_index_utils.rs b/crates/ra_ide_db/src/line_index_utils.rs
index 039a12c0d..7fa6fc448 100644
--- a/crates/ra_ide_db/src/line_index_utils.rs
+++ b/crates/ra_ide_db/src/line_index_utils.rs
@@ -10,7 +10,7 @@
 use std::convert::TryInto;
 
 use ra_syntax::{TextRange, TextSize};
-use ra_text_edit::{AtomTextEdit, TextEdit};
+use ra_text_edit::{Indel, TextEdit};
 
 use crate::line_index::{LineCol, LineIndex, Utf16Char};
 
@@ -182,14 +182,14 @@ struct TranslatedEdit<'a> {
 }
 
 struct Edits<'a> {
-    edits: &'a [AtomTextEdit],
+    edits: &'a [Indel],
     current: Option<TranslatedEdit<'a>>,
     acc_diff: i64,
 }
 
 impl<'a> Edits<'a> {
     fn from_text_edit(text_edit: &'a TextEdit) -> Edits<'a> {
-        let mut x = Edits { edits: text_edit.as_atoms(), current: None, acc_diff: 0 };
+        let mut x = Edits { edits: text_edit.as_indels(), current: None, acc_diff: 0 };
         x.advance_edit();
         x
     }
diff --git a/crates/ra_ide_db/src/marks.rs b/crates/ra_ide_db/src/marks.rs
index 03b4be21c..386fe605c 100644
--- a/crates/ra_ide_db/src/marks.rs
+++ b/crates/ra_ide_db/src/marks.rs
@@ -2,6 +2,7 @@
 
 test_utils::marks![
     goto_def_for_macros
+    goto_def_for_use_alias
     goto_def_for_methods
     goto_def_for_fields
     goto_def_for_record_fields
diff --git a/crates/ra_ide_db/src/source_change.rs b/crates/ra_ide_db/src/source_change.rs
new file mode 100644
index 000000000..af81a91a4
--- /dev/null
+++ b/crates/ra_ide_db/src/source_change.rs
@@ -0,0 +1,120 @@
+//! This modules defines type to represent changes to the source code, that flow
+//! from the server to the client.
+//!
+//! It can be viewed as a dual for `AnalysisChange`.
+
+use ra_db::{FileId, FilePosition, RelativePathBuf, SourceRootId};
+use ra_text_edit::{TextEdit, TextSize};
+
+#[derive(Debug, Clone)]
+pub struct SourceChange {
+    /// For display in the undo log in the editor
+    pub label: String,
+    pub source_file_edits: Vec<SourceFileEdit>,
+    pub file_system_edits: Vec<FileSystemEdit>,
+    pub cursor_position: Option<FilePosition>,
+}
+
+impl SourceChange {
+    /// Creates a new SourceChange with the given label
+    /// from the edits.
+    pub fn from_edits<L: Into<String>>(
+        label: L,
+        source_file_edits: Vec<SourceFileEdit>,
+        file_system_edits: Vec<FileSystemEdit>,
+    ) -> Self {
+        SourceChange {
+            label: label.into(),
+            source_file_edits,
+            file_system_edits,
+            cursor_position: None,
+        }
+    }
+
+    /// Creates a new SourceChange with the given label,
+    /// containing only the given `SourceFileEdits`.
+    pub fn source_file_edits<L: Into<String>>(label: L, edits: Vec<SourceFileEdit>) -> Self {
+        let label = label.into();
+        assert!(label.starts_with(char::is_uppercase));
+        SourceChange {
+            label: label,
+            source_file_edits: edits,
+            file_system_edits: vec![],
+            cursor_position: None,
+        }
+    }
+
+    /// Creates a new SourceChange with the given label,
+    /// containing only the given `FileSystemEdits`.
+    pub(crate) fn file_system_edits<L: Into<String>>(label: L, edits: Vec<FileSystemEdit>) -> Self {
+        SourceChange {
+            label: label.into(),
+            source_file_edits: vec![],
+            file_system_edits: edits,
+            cursor_position: None,
+        }
+    }
+
+    /// Creates a new SourceChange with the given label,
+    /// containing only a single `SourceFileEdit`.
+    pub fn source_file_edit<L: Into<String>>(label: L, edit: SourceFileEdit) -> Self {
+        SourceChange::source_file_edits(label, vec![edit])
+    }
+
+    /// Creates a new SourceChange with the given label
+    /// from the given `FileId` and `TextEdit`
+    pub fn source_file_edit_from<L: Into<String>>(
+        label: L,
+        file_id: FileId,
+        edit: TextEdit,
+    ) -> Self {
+        SourceChange::source_file_edit(label, SourceFileEdit { file_id, edit })
+    }
+
+    /// Creates a new SourceChange with the given label
+    /// from the given `FileId` and `TextEdit`
+    pub fn file_system_edit<L: Into<String>>(label: L, edit: FileSystemEdit) -> Self {
+        SourceChange::file_system_edits(label, vec![edit])
+    }
+
+    /// Sets the cursor position to the given `FilePosition`
+    pub fn with_cursor(mut self, cursor_position: FilePosition) -> Self {
+        self.cursor_position = Some(cursor_position);
+        self
+    }
+
+    /// Sets the cursor position to the given `FilePosition`
+    pub fn with_cursor_opt(mut self, cursor_position: Option<FilePosition>) -> Self {
+        self.cursor_position = cursor_position;
+        self
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct SourceFileEdit {
+    pub file_id: FileId,
+    pub edit: TextEdit,
+}
+
+#[derive(Debug, Clone)]
+pub enum FileSystemEdit {
+    CreateFile { source_root: SourceRootId, path: RelativePathBuf },
+    MoveFile { src: FileId, dst_source_root: SourceRootId, dst_path: RelativePathBuf },
+}
+
+pub struct SingleFileChange {
+    pub label: String,
+    pub edit: TextEdit,
+    pub cursor_position: Option<TextSize>,
+}
+
+impl SingleFileChange {
+    pub fn into_source_change(self, file_id: FileId) -> SourceChange {
+        SourceChange {
+            label: self.label,
+            source_file_edits: vec![SourceFileEdit { file_id, edit: self.edit }],
+            file_system_edits: Vec::new(),
+            cursor_position: self.cursor_position.map(|offset| FilePosition { file_id, offset }),
+        }
+    }
+}