4 files changed, 132 insertions, 29 deletions

diff --git a/crates/ra_hir/src/code_model.rs b/crates/ra_hir/src/code_model.rs
index 2944926e6..dca5f27b2 100644
--- a/crates/ra_hir/src/code_model.rs
+++ b/crates/ra_hir/src/code_model.rs
@@ -480,6 +480,14 @@ impl Adt {
     pub fn krate(self, db: &impl HirDatabase) -> Option<Crate> {
         Some(self.module(db).krate())
     }
+
+    pub fn name(&self, db: &impl HirDatabase) -> Name {
+        match self {
+            Adt::Struct(s) => s.name(db),
+            Adt::Union(u) => u.name(db),
+            Adt::Enum(e) => e.name(db),
+        }
+    }
 }
 
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
@@ -507,6 +515,14 @@ impl VariantDef {
         }
     }
 
+    pub fn name(&self, db: &impl HirDatabase) -> Name {
+        match self {
+            VariantDef::Struct(s) => s.name(db),
+            VariantDef::Union(u) => u.name(db),
+            VariantDef::EnumVariant(e) => e.name(db),
+        }
+    }
+
     pub(crate) fn variant_data(self, db: &impl DefDatabase) -> Arc<VariantData> {
         match self {
             VariantDef::Struct(it) => it.variant_data(db),
@@ -534,6 +550,14 @@ impl DefWithBody {
             DefWithBody::Static(s) => s.module(db),
         }
     }
+
+    pub fn name(self, db: &impl HirDatabase) -> Option<Name> {
+        match self {
+            DefWithBody::Function(f) => Some(f.name(db)),
+            DefWithBody::Static(s) => s.name(db),
+            DefWithBody::Const(c) => c.name(db),
+        }
+    }
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
diff --git a/crates/ra_ide/src/display.rs b/crates/ra_ide/src/display.rs
index 1c26a8697..eaeaaa2b4 100644
--- a/crates/ra_ide/src/display.rs
+++ b/crates/ra_ide/src/display.rs
@@ -68,17 +68,23 @@ pub(crate) fn macro_label(node: &ast::MacroCall) -> String {
 }
 
 pub(crate) fn rust_code_markup<CODE: AsRef<str>>(val: CODE) -> String {
-    rust_code_markup_with_doc::<_, &str>(val, None)
+    rust_code_markup_with_doc::<_, &str>(val, None, None)
 }
 
-pub(crate) fn rust_code_markup_with_doc<CODE, DOC>(val: CODE, doc: Option<DOC>) -> String
+pub(crate) fn rust_code_markup_with_doc<CODE, DOC>(
+    val: CODE,
+    doc: Option<DOC>,
+    mod_path: Option<String>,
+) -> String
 where
     CODE: AsRef<str>,
     DOC: AsRef<str>,
 {
+    let mod_path =
+        mod_path.filter(|path| !path.is_empty()).map(|path| path + "\n").unwrap_or_default();
     if let Some(doc) = doc {
-        format!("```rust\n{}\n```\n\n{}", val.as_ref(), doc.as_ref())
+        format!("```rust\n{}{}\n```\n\n{}", mod_path, val.as_ref(), doc.as_ref())
     } else {
-        format!("```rust\n{}\n```", val.as_ref())
+        format!("```rust\n{}{}\n```", mod_path, val.as_ref())
     }
 }
diff --git a/crates/ra_ide/src/hover.rs b/crates/ra_ide/src/hover.rs
index e9c682557..da3b67943 100644
--- a/crates/ra_ide/src/hover.rs
+++ b/crates/ra_ide/src/hover.rs
@@ -1,6 +1,8 @@
 //! FIXME: write short doc here
 
-use hir::{Adt, HasSource, HirDisplay, Semantics};
+use hir::{
+    Adt, AsAssocItem, AssocItemContainer, HasSource, HirDisplay, ModuleDef, ModuleSource, Semantics,
+};
 use ra_ide_db::{
     defs::{classify_name, classify_name_ref, Definition},
     RootDatabase,
@@ -16,6 +18,8 @@ use crate::{
     display::{macro_label, rust_code_markup, rust_code_markup_with_doc, ShortLabel},
     FilePosition, RangeInfo,
 };
+use itertools::Itertools;
+use std::iter::once;
 
 /// Contains the results when hovering over an item
 #[derive(Debug, Clone)]
@@ -83,44 +87,86 @@ impl HoverResult {
     }
 }
 
-fn hover_text(docs: Option<String>, desc: Option<String>) -> Option<String> {
-    match (desc, docs) {
-        (Some(desc), docs) => Some(rust_code_markup_with_doc(desc, docs)),
-        (None, Some(docs)) => Some(docs),
+fn hover_text(
+    docs: Option<String>,
+    desc: Option<String>,
+    mod_path: Option<String>,
+) -> Option<String> {
+    match (desc, docs, mod_path) {
+        (Some(desc), docs, mod_path) => Some(rust_code_markup_with_doc(desc, docs, mod_path)),
+        (None, Some(docs), _) => Some(docs),
         _ => None,
     }
 }
 
+fn definition_owner_name(db: &RootDatabase, def: &Definition) -> Option<String> {
+    match def {
+        Definition::StructField(f) => Some(f.parent_def(db).name(db)),
+        Definition::Local(l) => l.parent(db).name(db),
+        Definition::ModuleDef(md) => match md {
+            ModuleDef::Function(f) => match f.as_assoc_item(db)?.container(db) {
+                AssocItemContainer::Trait(t) => Some(t.name(db)),
+                AssocItemContainer::ImplDef(i) => i.target_ty(db).as_adt().map(|adt| adt.name(db)),
+            },
+            ModuleDef::EnumVariant(e) => Some(e.parent_enum(db).name(db)),
+            _ => None,
+        },
+        Definition::SelfType(i) => i.target_ty(db).as_adt().map(|adt| adt.name(db)),
+        _ => None,
+    }
+    .map(|name| name.to_string())
+}
+
+fn determine_mod_path(db: &RootDatabase, def: &Definition) -> Option<String> {
+    let mod_path = def.module(db).map(|module| {
+        once(db.get_crate_original_name(&module.krate().into()))
+            .chain(
+                module
+                    .path_to_root(db)
+                    .into_iter()
+                    .rev()
+                    .map(|it| it.name(db).map(|name| name.to_string())),
+            )
+            .chain(once(definition_owner_name(db, def)))
+            .filter_map(std::convert::identity)
+            .join("::")
+    });
+    mod_path
+}
+
 fn hover_text_from_name_kind(db: &RootDatabase, def: Definition) -> Option<String> {
+    let mod_path = determine_mod_path(db, &def);
     return match def {
         Definition::Macro(it) => {
             let src = it.source(db);
-            hover_text(src.value.doc_comment_text(), Some(macro_label(&src.value)))
+            hover_text(src.value.doc_comment_text(), Some(macro_label(&src.value)), mod_path)
         }
         Definition::StructField(it) => {
             let src = it.source(db);
             match src.value {
-                hir::FieldSource::Named(it) => hover_text(it.doc_comment_text(), it.short_label()),
+                hir::FieldSource::Named(it) => {
+                    hover_text(it.doc_comment_text(), it.short_label(), mod_path)
+                }
                 _ => None,
             }
         }
         Definition::ModuleDef(it) => match it {
-            hir::ModuleDef::Module(it) => match it.definition_source(db).value {
-                hir::ModuleSource::Module(it) => {
-                    hover_text(it.doc_comment_text(), it.short_label())
+            ModuleDef::Module(it) => match it.definition_source(db).value {
+                ModuleSource::Module(it) => {
+                    hover_text(it.doc_comment_text(), it.short_label(), mod_path)
                 }
                 _ => None,
             },
-            hir::ModuleDef::Function(it) => from_def_source(db, it),
-            hir::ModuleDef::Adt(Adt::Struct(it)) => from_def_source(db, it),
-            hir::ModuleDef::Adt(Adt::Union(it)) => from_def_source(db, it),
-            hir::ModuleDef::Adt(Adt::Enum(it)) => from_def_source(db, it),
-            hir::ModuleDef::EnumVariant(it) => from_def_source(db, it),
-            hir::ModuleDef::Const(it) => from_def_source(db, it),
-            hir::ModuleDef::Static(it) => from_def_source(db, it),
-            hir::ModuleDef::Trait(it) => from_def_source(db, it),
-            hir::ModuleDef::TypeAlias(it) => from_def_source(db, it),
-            hir::ModuleDef::BuiltinType(it) => Some(it.to_string()),
+            ModuleDef::Function(it) => from_def_source(db, it, mod_path),
+            ModuleDef::Adt(Adt::Struct(it)) => from_def_source(db, it, mod_path),
+            ModuleDef::Adt(Adt::Union(it)) => from_def_source(db, it, mod_path),
+            ModuleDef::Adt(Adt::Enum(it)) => from_def_source(db, it, mod_path),
+            ModuleDef::EnumVariant(it) => from_def_source(db, it, mod_path),
+            ModuleDef::Const(it) => from_def_source(db, it, mod_path),
+            ModuleDef::Static(it) => from_def_source(db, it, mod_path),
+            ModuleDef::Trait(it) => from_def_source(db, it, mod_path),
+            ModuleDef::TypeAlias(it) => from_def_source(db, it, mod_path),
+            ModuleDef::BuiltinType(it) => Some(it.to_string()),
         },
         Definition::Local(it) => {
             Some(rust_code_markup(it.ty(db).display_truncated(db, None).to_string()))
@@ -131,13 +177,13 @@ fn hover_text_from_name_kind(db: &RootDatabase, def: Definition) -> Option<Strin
         }
     };
 
-    fn from_def_source<A, D>(db: &RootDatabase, def: D) -> Option<String>
+    fn from_def_source<A, D>(db: &RootDatabase, def: D, mod_path: Option<String>) -> Option<String>
     where
         D: HasSource<Ast = A>,
         A: ast::DocCommentsOwner + ast::NameOwner + ShortLabel,
     {
         let src = def.source(db);
-        hover_text(src.value.doc_comment_text(), src.value.short_label())
+        hover_text(src.value.doc_comment_text(), src.value.short_label(), mod_path)
     }
 }
 
@@ -345,7 +391,7 @@ mod tests {
                 };
             }
         "#,
-            &["field_a: u32"],
+            &["Foo\nfield_a: u32"],
         );
 
         // Hovering over the field in the definition
@@ -362,7 +408,7 @@ mod tests {
                 };
             }
         "#,
-            &["field_a: u32"],
+            &["Foo\nfield_a: u32"],
         );
     }
 
@@ -415,7 +461,7 @@ fn main() {
             ",
         );
         let hover = analysis.hover(position).unwrap().unwrap();
-        assert_eq!(trim_markup_opt(hover.info.first()), Some("Some"));
+        assert_eq!(trim_markup_opt(hover.info.first()), Some("Option\nSome"));
 
         let (analysis, position) = single_file_with_position(
             "
@@ -442,6 +488,7 @@ fn main() {
             }
         "#,
             &["
+Option
 None
 ```
 
@@ -462,6 +509,7 @@ The None variant
             }
         "#,
             &["
+Option
 Some
 ```
 
@@ -815,4 +863,25 @@ fn func(foo: i32) { if true { <|>foo; }; }
             &["fn foo()\n```\n\n<- `\u{3000}` here"],
         );
     }
+
+    #[test]
+    fn zzz() {
+        check_hover_result(
+            "
+            //- /main.rs
+            mod vvv {
+                pub struct Test;
+
+                impl Test {
+                    pub fn whatever() {}
+                }
+            }
+
+            fn main() {
+                vvv::Test::what<|>ever();
+            }
+            ",
+            &["vvv::Test\npub fn whatever()"],
+        );
+    }
 }
diff --git a/crates/ra_ide_db/src/lib.rs b/crates/ra_ide_db/src/lib.rs
index 79f48c9e3..efa472c7d 100644
--- a/crates/ra_ide_db/src/lib.rs
+++ b/crates/ra_ide_db/src/lib.rs
@@ -104,6 +104,10 @@ impl RootDatabase {
         db.query_mut(hir::db::MacroExpandQuery).set_lru_capacity(lru_capacity);
         db
     }
+
+    pub fn get_crate_original_name(&self, crate_id: &CrateId) -> Option<String> {
+        self.debug_data.crate_names.get(crate_id).cloned()
+    }
 }
 
 impl salsa::ParallelDatabase for RootDatabase {