fix: Show what file paths were expected for unresolved modules

Cargo.lock

@@ -504,6 +504,7 @@ name = "hir_def"
 version = "0.0.0"
 dependencies = [
  "anymap",
+ "arrayvec",
  "base_db",
  "cfg",
  "cov-mark",

crates/hir/src/diagnostics.rs

@@ -54,7 +54,7 @@ diagnostics![
 #[derive(Debug)]
 pub struct UnresolvedModule {
     pub decl: InFile<AstPtr<ast::Module>>,
-    pub candidate: String,
+    pub candidates: Box<[String]>,
 }
 
 #[derive(Debug)]

crates/hir/src/lib.rs

@@ -593,12 +593,12 @@ impl Module {
 
 fn emit_def_diagnostic(db: &dyn HirDatabase, acc: &mut Vec<AnyDiagnostic>, diag: &DefDiagnostic) {
     match &diag.kind {
-        DefDiagnosticKind::UnresolvedModule { ast: declaration, candidate } => {
+        DefDiagnosticKind::UnresolvedModule { ast: declaration, candidates } => {
             let decl = declaration.to_node(db.upcast());
             acc.push(
                 UnresolvedModule {
                     decl: InFile::new(declaration.file_id, AstPtr::new(&decl)),
-                    candidate: candidate.clone(),
+                    candidates: candidates.clone(),
                 }
                 .into(),
             )

crates/hir_def/Cargo.toml

@@ -24,6 +24,7 @@ fst = { version = "0.4", default-features = false }
 itertools = "0.10.0"
 indexmap = "1.7.0"
 smallvec = "1.4.0"
+arrayvec = "0.7.2"
 la-arena = { version = "0.3.0", path = "../../lib/arena" }
 
 stdx = { path = "../stdx", version = "0.0.0" }

crates/hir_def/src/item_tree.rs

@@ -709,7 +709,7 @@ pub enum ModKind {
     Inline { items: Box<[ModItem]> },
 
     /// `mod m;`
-    Outline {},
+    Outline,
 }
 
 #[derive(Debug, Clone, Eq, PartialEq)]

crates/hir_def/src/item_tree/lower.rs

@@ -401,7 +401,7 @@ impl<'a> Ctx<'a> {
         let name = module.name()?.as_name();
         let visibility = self.lower_visibility(module);
         let kind = if module.semicolon_token().is_some() {
-            ModKind::Outline {}
+            ModKind::Outline
         } else {
             ModKind::Inline {
                 items: module

crates/hir_def/src/item_tree/pretty.rs

@@ -423,7 +423,7 @@ impl<'a> Printer<'a> {
                         });
                         wln!(self, "}}");
                     }
-                    ModKind::Outline {} => {
+                    ModKind::Outline => {
                         wln!(self, ";");
                     }
                 }

crates/hir_def/src/nameres/collector.rs

@@ -1713,7 +1713,7 @@ impl ModCollector<'_, '_> {
                 }
             }
             // out of line module, resolve, parse and recurse
-            ModKind::Outline {} => {
+            ModKind::Outline => {
                 let ast_id = AstId::new(self.tree_id.file_id(), module.ast_id);
                 let db = self.def_collector.db;
                 match self.mod_dir.resolve_declaration(db, self.file_id(), &module.name, path_attr)
@@ -1751,9 +1751,9 @@ impl ModCollector<'_, '_> {
                             }
                         }
                     }
-                    Err(candidate) => {
+                    Err(candidates) => {
                         self.def_collector.def_map.diagnostics.push(
-                            DefDiagnostic::unresolved_module(self.module_id, ast_id, candidate),
+                            DefDiagnostic::unresolved_module(self.module_id, ast_id, candidates),
                         );
                     }
                 };

crates/hir_def/src/nameres/diagnostics.rs

@@ -15,7 +15,7 @@ use crate::{
 
 #[derive(Debug, PartialEq, Eq)]
 pub enum DefDiagnosticKind {
-    UnresolvedModule { ast: AstId<ast::Module>, candidate: String },
+    UnresolvedModule { ast: AstId<ast::Module>, candidates: Box<[String]> },
 
     UnresolvedExternCrate { ast: AstId<ast::ExternCrate> },
 
@@ -46,11 +46,11 @@ impl DefDiagnostic {
     pub(super) fn unresolved_module(
         container: LocalModuleId,
         declaration: AstId<ast::Module>,
-        candidate: String,
+        candidates: Box<[String]>,
     ) -> Self {
         Self {
             in_module: container,
-            kind: DefDiagnosticKind::UnresolvedModule { ast: declaration, candidate },
+            kind: DefDiagnosticKind::UnresolvedModule { ast: declaration, candidates },
         }
     }
 

crates/hir_def/src/nameres/mod_resolution.rs

@@ -1,4 +1,5 @@
 //! This module resolves `mod foo;` declaration to file.
+use arrayvec::ArrayVec;
 use base_db::{AnchoredPath, FileId};
 use hir_expand::name::Name;
 use limit::Limit;
@@ -63,22 +64,21 @@ impl ModDir {
         file_id: HirFileId,
         name: &Name,
         attr_path: Option<&SmolStr>,
-    ) -> Result<(FileId, bool, ModDir), String> {
+    ) -> Result<(FileId, bool, ModDir), Box<[String]>> {
         let orig_file_id = file_id.original_file(db.upcast());
 
-        let mut candidate_files = Vec::new();
+        let mut candidate_files = ArrayVec::<_, 2>::new();
         match attr_path {
             Some(attr_path) => {
                 candidate_files.push(self.dir_path.join_attr(attr_path, self.root_non_dir_owner))
             }
+            None if file_id.is_include_macro(db.upcast()) => {
+                candidate_files.push(format!("{}.rs", name));
+                candidate_files.push(format!("{}/mod.rs", name));
+            }
             None => {
-                if file_id.is_include_macro(db.upcast()) {
+                candidate_files.push(format!("{}{}.rs", self.dir_path.0, name));
-                    candidate_files.push(format!("{}.rs", name));
+                candidate_files.push(format!("{}{}/mod.rs", self.dir_path.0, name));
-                    candidate_files.push(format!("{}/mod.rs", name));
-                } else {
-                    candidate_files.push(format!("{}{}.rs", self.dir_path.0, name));
-                    candidate_files.push(format!("{}{}/mod.rs", self.dir_path.0, name));
-                }
             }
         };
 
@@ -97,7 +97,7 @@ impl ModDir {
                 }
             }
         }
-        Err(candidate_files.remove(0))
+        Err(candidate_files.into_iter().collect())
     }
 }
 

crates/ide_diagnostics/src/handlers/unresolved_module.rs

@@ -1,5 +1,6 @@
 use hir::db::AstDatabase;
 use ide_db::{assists::Assist, base_db::AnchoredPathBuf, source_change::FileSystemEdit};
+use itertools::Itertools;
 use syntax::AstNode;
 
 use crate::{fix, Diagnostic, DiagnosticsContext};
@@ -13,7 +14,17 @@ pub(crate) fn unresolved_module(
 ) -> Diagnostic {
     Diagnostic::new(
         "unresolved-module",
-        "unresolved module",
+        match &*d.candidates {
+            [] => "unresolved module".to_string(),
+            [candidate] => format!("unresolved module, can't find module file: {}", candidate),
+            [candidates @ .., last] => {
+                format!(
+                    "unresolved module, can't find module file: {}, or {}",
+                    candidates.iter().format(", "),
+                    last
+                )
+            }
+        },
         ctx.sema.diagnostics_display_range(d.decl.clone().map(|it| it.into())).range,
     )
     .with_fixes(fixes(ctx, d))
@@ -22,19 +33,26 @@ pub(crate) fn unresolved_module(
 fn fixes(ctx: &DiagnosticsContext<'_>, d: &hir::UnresolvedModule) -> Option<Vec<Assist>> {
     let root = ctx.sema.db.parse_or_expand(d.decl.file_id)?;
     let unresolved_module = d.decl.value.to_node(&root);
-    Some(vec![fix(
+    Some(
-        "create_module",
+        d.candidates
-        "Create module",
+            .iter()
-        FileSystemEdit::CreateFile {
+            .map(|candidate| {
-            dst: AnchoredPathBuf {
+                fix(
-                anchor: d.decl.file_id.original_file(ctx.sema.db),
+                    "create_module",
-                path: d.candidate.clone(),
+                    "Create module",
-            },
+                    FileSystemEdit::CreateFile {
-            initial_contents: "".to_string(),
+                        dst: AnchoredPathBuf {
-        }
+                            anchor: d.decl.file_id.original_file(ctx.sema.db),
-        .into(),
+                            path: candidate.clone(),
-        unresolved_module.syntax().text_range(),
+                        },
-    )])
+                        initial_contents: "".to_string(),
+                    }
+                    .into(),
+                    unresolved_module.syntax().text_range(),
+                )
+            })
+            .collect(),
+    )
 }
 
 #[cfg(test)]
@@ -50,7 +68,7 @@ mod tests {
 //- /lib.rs
 mod foo;
   mod bar;
-//^^^^^^^^ 💡 error: unresolved module
+//^^^^^^^^ 💡 error: unresolved module, can't find module file: bar.rs, or bar/mod.rs
 mod baz {}
 //- /foo.rs
 "#,
@@ -67,7 +85,7 @@ mod baz {}
                         code: DiagnosticCode(
                             "unresolved-module",
                         ),
-                        message: "unresolved module",
+                        message: "unresolved module, can't find module file: foo.rs, or foo/mod.rs",
                         range: 0..8,
                         severity: Error,
                         unused: false,
@@ -100,6 +118,32 @@ mod baz {}
                                         },
                                     ),
                                 },
+                                Assist {
+                                    id: AssistId(
+                                        "create_module",
+                                        QuickFix,
+                                    ),
+                                    label: "Create module",
+                                    group: None,
+                                    target: 0..8,
+                                    source_change: Some(
+                                        SourceChange {
+                                            source_file_edits: {},
+                                            file_system_edits: [
+                                                CreateFile {
+                                                    dst: AnchoredPathBuf {
+                                                        anchor: FileId(
+                                                            0,
+                                                        ),
+                                                        path: "foo/mod.rs",
+                                                    },
+                                                    initial_contents: "",
+                                                },
+                                            ],
+                                            is_snippet: false,
+                                        },
+                                    ),
+                                },
                             ],
                         ),
                     },

crates/rust-analyzer/tests/slow-tests/main.rs

@@ -463,18 +463,32 @@ fn main() {}
             partial_result_params: PartialResultParams::default(),
             work_done_progress_params: WorkDoneProgressParams::default(),
         },
-        json!([{
+        json!([
-            "edit": {
+            {
-              "documentChanges": [
+                "title": "Create module",
-                {
+                "kind": "quickfix",
-                  "kind": "create",
+                "edit": {
-                  "uri": "file:///[..]/src/bar.rs"
+                "documentChanges": [
+                    {
+                    "kind": "create",
+                    "uri": "file://[..]/src/bar.rs"
+                    }
+                ]
                 }
-              ]
             },
-            "kind": "quickfix",
+            {
-            "title": "Create module"
+                "title": "Create module",
-        }]),
+                "kind": "quickfix",
+                "edit": {
+                "documentChanges": [
+                    {
+                    "kind": "create",
+                    "uri": "file://[..]src/bar/mod.rs"
+                    }
+                ]
+                }
+            }
+        ]),
     );
 
     server.request::<CodeActionRequest>(
@@ -492,7 +506,7 @@ fn main() {}
 #[test]
 fn test_missing_module_code_action_in_json_project() {
     if skip_slow_tests() {
-        return;
+        // return;
     }
 
     let tmp_dir = TestDir::new();
@@ -533,18 +547,32 @@ fn main() {{}}
             partial_result_params: PartialResultParams::default(),
             work_done_progress_params: WorkDoneProgressParams::default(),
         },
-        json!([{
+        json!([
-            "edit": {
+            {
-              "documentChanges": [
+                "title": "Create module",
-                {
+                "kind": "quickfix",
-                  "kind": "create",
+                "edit": {
-                  "uri": "file://[..]/src/bar.rs"
+                "documentChanges": [
+                    {
+                    "kind": "create",
+                    "uri": "file://[..]/src/bar.rs"
+                    }
+                ]
                 }
-              ]
             },
-            "kind": "quickfix",
+            {
-            "title": "Create module"
+                "title": "Create module",
-        }]),
+                "kind": "quickfix",
+                "edit": {
+                "documentChanges": [
+                    {
+                    "kind": "create",
+                    "uri": "file://[..]src/bar/mod.rs"
+                    }
+                ]
+                }
+            }
+        ]),
     );
 
     server.request::<CodeActionRequest>(