4 files changed, 171 insertions, 65 deletions

diff --git a/crates/libanalysis/Cargo.toml b/crates/libanalysis/Cargo.toml
index a8ef5e5f4..5aca84f0e 100644
--- a/crates/libanalysis/Cargo.toml
+++ b/crates/libanalysis/Cargo.toml
@@ -4,6 +4,7 @@ version = "0.1.0"
 authors = ["Aleksey Kladov <[email protected]>"]
 
 [dependencies]
+relative-path = "0.3.7"
 log = "0.4.2"
 failure = "0.1.2"
 parking_lot = "0.6.3"
diff --git a/crates/libanalysis/src/lib.rs b/crates/libanalysis/src/lib.rs
index fe2c3c2e6..96d10a087 100644
--- a/crates/libanalysis/src/lib.rs
+++ b/crates/libanalysis/src/lib.rs
@@ -8,13 +8,13 @@ extern crate libsyntax2;
 extern crate libeditor;
 extern crate fst;
 extern crate rayon;
+extern crate relative_path;
 
 mod symbol_index;
 mod module_map;
 
 use std::{
     fmt,
-    path::{Path, PathBuf},
     panic,
     sync::{
         Arc,
@@ -24,6 +24,7 @@ use std::{
     time::Instant,
 };
 
+use relative_path::{RelativePath,RelativePathBuf};
 use once_cell::sync::OnceCell;
 use rayon::prelude::*;
 
@@ -37,13 +38,16 @@ use libeditor::{Diagnostic, LineIndex, FileSymbol, find_node_at_offset};
 
 use self::{
     symbol_index::FileSymbols,
-    module_map::{ModuleMap, ChangeKind},
+    module_map::{ModuleMap, ChangeKind, Problem},
 };
 pub use self::symbol_index::Query;
 
 pub type Result<T> = ::std::result::Result<T, ::failure::Error>;
 
-pub type FileResolver = dyn Fn(FileId, &Path) -> Option<FileId> + Send + Sync;
+pub trait FileResolver: Send + Sync + 'static {
+    fn file_stem(&self, id: FileId) -> String;
+    fn resolve(&self, id: FileId, path: &RelativePath) -> Option<FileId>;
+}
 
 #[derive(Debug)]
 pub struct WorldState {
@@ -84,7 +88,7 @@ impl WorldState {
 
     pub fn snapshot(
         &self,
-        file_resolver: impl Fn(FileId, &Path) -> Option<FileId> + 'static + Send + Sync,
+        file_resolver: impl FileResolver,
     ) -> World {
         World {
             needs_reindex: AtomicBool::new(false),
@@ -132,8 +136,20 @@ impl WorldState {
 }
 
 #[derive(Debug)]
-pub enum QuickFix {
-    CreateFile(PathBuf),
+pub struct QuickFix {
+    pub fs_ops: Vec<FsOp>,
+}
+
+#[derive(Debug)]
+pub enum FsOp {
+    CreateFile {
+        anchor: FileId,
+        path: RelativePathBuf,
+    },
+    MoveFile {
+        file: FileId,
+        path: RelativePathBuf,
+    }
 }
 
 impl World {
@@ -221,20 +237,49 @@ impl World {
             .into_iter()
             .map(|d| (d, None))
             .collect::<Vec<_>>();
-        for module in syntax.ast().modules() {
-            if module.has_semi() && self.resolve_module(file_id, module).is_empty() {
-                if let Some(name) = module.name() {
-                    let d = Diagnostic {
-                        range: name.syntax().range(),
-                        msg: "unresolved module".to_string(),
-                    };
-                    let quick_fix = self.data.module_map.suggested_child_mod_path(module)
-                        .map(QuickFix::CreateFile);
-
-                    res.push((d, quick_fix))
-                }
+
+        self.data.module_map.problems(
+            file_id,
+            &*self.file_resolver,
+            &|file_id| self.file_syntax(file_id).unwrap(),
+            |name_node, problem| {
+                let (diag, fix) = match problem {
+                    Problem::UnresolvedModule { candidate } => {
+                        let diag = Diagnostic {
+                            range: name_node.syntax().range(),
+                            msg: "unresolved module".to_string(),
+                        };
+                        let fix = QuickFix {
+                            fs_ops: vec![FsOp::CreateFile {
+                                anchor: file_id,
+                                path: candidate.clone(),
+                            }]
+                        };
+                        (diag, fix)
+                    }
+                    Problem::NotDirOwner { move_to, candidate } => {
+                        let diag = Diagnostic {
+                            range: name_node.syntax().range(),
+                            msg: "can't declare module at this location".to_string(),
+                        };
+                        let fix = QuickFix {
+                            fs_ops: vec![
+                                FsOp::MoveFile {
+                                    file: file_id,
+                                    path: move_to.clone(),
+                                },
+                                FsOp::CreateFile {
+                                    anchor: file_id,
+                                    path: move_to.join(candidate),
+                                }
+                            ],
+                        };
+                        (diag, fix)
+                    }
+                };
+                res.push((diag, Some(fix)))
             }
-        }
+        );
         Ok(res)
     }
 
diff --git a/crates/libanalysis/src/module_map.rs b/crates/libanalysis/src/module_map.rs
index 4f480591e..b65569c46 100644
--- a/crates/libanalysis/src/module_map.rs
+++ b/crates/libanalysis/src/module_map.rs
@@ -1,6 +1,4 @@
-use std::{
-    path::{PathBuf},
-};
+use relative_path::RelativePathBuf;
 
 use parking_lot::{RwLock, RwLockReadGuard, RwLockWriteGuard};
 use libsyntax2::{
@@ -43,6 +41,18 @@ struct Link {
     owner: ModuleId,
     syntax: SyntaxNode,
     points_to: Vec<ModuleId>,
+    problem: Option<Problem>,
+}
+
+#[derive(Clone, Debug)]
+pub enum Problem {
+    UnresolvedModule {
+        candidate: RelativePathBuf,
+    },
+    NotDirOwner {
+        move_to: RelativePathBuf,
+        candidate: RelativePathBuf,
+    }
 }
 
 impl ModuleMap {
@@ -93,9 +103,24 @@ impl ModuleMap {
         res
     }
 
-    pub fn suggested_child_mod_path(&self, m: ast::Module) -> Option<PathBuf> {
-        let name = m.name()?;
-        Some(PathBuf::from(format!("../{}.rs", name.text())))
+    pub fn problems(
+        &self,
+        file: FileId,
+        file_resolver: &FileResolver,
+        syntax_provider: &SyntaxProvider,
+        mut cb: impl FnMut(ast::Name, &Problem),
+    ) {
+        let module = self.file2module(file);
+        let links = self.links(file_resolver, syntax_provider);
+        links
+            .links
+            .iter()
+            .filter(|link| link.owner == module)
+            .filter_map(|link| {
+                let problem = link.problem.as_ref()?;
+                Some((link, problem))
+            })
+            .for_each(|(link, problem)| cb(link.name_node(), problem))
     }
 
     fn links(
@@ -176,14 +201,17 @@ impl Link {
             owner,
             syntax: module.syntax().owned(),
             points_to: Vec::new(),
+            problem: None,
         };
         Some(link)
     }
 
     fn name(&self) -> SmolStr {
-        self.ast().name()
-            .unwrap()
-            .text()
+        self.name_node().text()
+    }
+
+    fn name_node(&self) -> ast::Name {
+        self.ast().name().unwrap()
     }
 
     fn ast(&self) -> ast::Module {
@@ -192,14 +220,30 @@ impl Link {
     }
 
     fn resolve(&mut self, file_resolver: &FileResolver) {
-        let name = self.name();
-        let paths = &[
-            PathBuf::from(format!("../{}.rs", name)),
-            PathBuf::from(format!("../{}/mod.rs", name)),
-        ];
-        self.points_to = paths.iter()
-            .filter_map(|path| file_resolver(self.owner.0, path))
-            .map(ModuleId)
-            .collect();
+        let mod_name = file_resolver.file_stem(self.owner.0);
+        let is_dir_owner =
+            mod_name == "mod" || mod_name == "lib" || mod_name == "main";
+
+        let file_mod = RelativePathBuf::from(format!("../{}.rs", self.name()));
+        let dir_mod = RelativePathBuf::from(format!("../{}/mod.rs", self.name()));
+        if is_dir_owner {
+            self.points_to = [&file_mod, &dir_mod].iter()
+                .filter_map(|path| file_resolver.resolve(self.owner.0, path))
+                .map(ModuleId)
+                .collect();
+            self.problem = if self.points_to.is_empty() {
+                Some(Problem::UnresolvedModule {
+                    candidate: file_mod,
+                })
+            } else {
+                None
+            }
+        } else {
+            self.points_to = Vec::new();
+            self.problem = Some(Problem::NotDirOwner {
+                move_to: RelativePathBuf::from(format!("../{}/mod.rs", mod_name)),
+                candidate: file_mod,
+            });
+        }
     }
 }
diff --git a/crates/libanalysis/tests/tests.rs b/crates/libanalysis/tests/tests.rs
index 7c2950ccc..e378ab986 100644
--- a/crates/libanalysis/tests/tests.rs
+++ b/crates/libanalysis/tests/tests.rs
@@ -1,11 +1,39 @@
 extern crate libanalysis;
+extern crate relative_path;
 extern crate test_utils;
 
-use std::path::PathBuf;
+use std::path::{Path};
 
-use libanalysis::{WorldState, FileId};
+use relative_path::RelativePath;
+use libanalysis::{WorldState, FileId, FileResolver};
 use test_utils::assert_eq_dbg;
 
+struct FileMap(&'static [(u32, &'static str)]);
+
+impl FileMap {
+    fn path(&self, id: FileId) -> &'static Path {
+        let s = self.0.iter()
+            .find(|it| it.0 == id.0)
+            .unwrap()
+            .1;
+        Path::new(s)
+    }
+}
+
+impl FileResolver for FileMap {
+    fn file_stem(&self, id: FileId) -> String {
+        self.path(id).file_stem().unwrap().to_str().unwrap().to_string()
+    }
+    fn resolve(&self, id: FileId, rel: &RelativePath) -> Option<FileId> {
+        let path = rel.to_path(self.path(id));
+        let path = path.to_str().unwrap();
+        let path = RelativePath::new(&path[1..]).normalize();
+        let &(id, _) = self.0.iter()
+            .find(|it| path == RelativePath::new(&it.1[1..]).normalize())?;
+        Some(FileId(id))
+    }
+}
+
 
 #[test]
 fn test_resolve_module() {
@@ -13,14 +41,10 @@ fn test_resolve_module() {
     world.change_file(FileId(1), Some("mod foo;".to_string()));
     world.change_file(FileId(2), Some("".to_string()));
 
-    let snap = world.snapshot(|id, path| {
-        assert_eq!(id, FileId(1));
-        if path == PathBuf::from("../foo/mod.rs") {
-            return None;
-        }
-        assert_eq!(path, PathBuf::from("../foo.rs"));
-        Some(FileId(2))
-    });
+    let snap = world.snapshot(FileMap(&[
+        (1, "/lib.rs"),
+        (2, "/foo.rs"),
+    ]));
     let symbols = snap.approximately_resolve_symbol(FileId(1), 4.into())
         .unwrap();
     assert_eq_dbg(
@@ -28,14 +52,10 @@ fn test_resolve_module() {
         &symbols,
     );
 
-    let snap = world.snapshot(|id, path| {
-        assert_eq!(id, FileId(1));
-        if path == PathBuf::from("../foo.rs") {
-            return None;
-        }
-        assert_eq!(path, PathBuf::from("../foo/mod.rs"));
-        Some(FileId(2))
-    });
+    let snap = world.snapshot(FileMap(&[
+        (1, "/lib.rs"),
+        (2, "/foo/mod.rs")
+    ]));
     let symbols = snap.approximately_resolve_symbol(FileId(1), 4.into())
         .unwrap();
     assert_eq_dbg(
@@ -49,11 +69,11 @@ fn test_unresolved_module_diagnostic() {
     let mut world = WorldState::new();
     world.change_file(FileId(1), Some("mod foo;".to_string()));
 
-    let snap = world.snapshot(|_id, _path| None);
+    let snap = world.snapshot(FileMap(&[(1, "/lib.rs")]));
     let diagnostics = snap.diagnostics(FileId(1)).unwrap();
     assert_eq_dbg(
         r#"[(Diagnostic { range: [4; 7), msg: "unresolved module" },
-             Some(CreateFile("../foo.rs")))]"#,
+             Some(QuickFix { fs_ops: [CreateFile { anchor: FileId(1), path: "../foo.rs" }] }))]"#,
         &diagnostics,
     );
 }
@@ -64,14 +84,10 @@ fn test_resolve_parent_module() {
     world.change_file(FileId(1), Some("mod foo;".to_string()));
     world.change_file(FileId(2), Some("".to_string()));
 
-    let snap = world.snapshot(|id, path| {
-        assert_eq!(id, FileId(1));
-        if path == PathBuf::from("../foo/mod.rs") {
-            return None;
-        }
-        assert_eq!(path, PathBuf::from("../foo.rs"));
-        Some(FileId(2))
-    });
+    let snap = world.snapshot(FileMap(&[
+        (1, "/lib.rs"),
+        (2, "/foo.rs"),
+    ]));
     let symbols = snap.parent_module(FileId(2));
     assert_eq_dbg(
         r#"[(FileId(1), FileSymbol { name: "foo", node_range: [0; 8), kind: MODULE })]"#,