feature: use statements language support

crates/mun_hir/Cargo.toml

@@ -23,9 +23,11 @@ once_cell = "1.4.0"
 ena = "0.14"
 drop_bomb = "0.1.4"
 either = "1.5.3"
-itertools = "0.9.0"
+itertools = "0.10.0"
+smallvec = "1.4.2"
 
 [dev-dependencies]
 insta = "0.16"
+text_trees = "0.1.2"
 parking_lot = "0.10"
 mun_test = { version = "=0.1.0", path = "../mun_test" }

crates/mun_hir/src/code_model/module.rs

@@ -1,7 +1,7 @@
 use super::{Function, Package, Struct, TypeAlias};
 use crate::ids::{ItemDefinitionId, ModuleId};
 use crate::primitive_type::PrimitiveType;
-use crate::{DiagnosticSink, FileId, HirDatabase};
+use crate::{DiagnosticSink, FileId, HirDatabase, Name};
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub struct Module {
@@ -23,6 +23,49 @@ impl Module {
             .find(|m| m.file_id(db) == Some(file))
     }
 
+    /// Returns the parent module of this module.
+    pub fn parent(self, db: &dyn HirDatabase) -> Option<Module> {
+        let module_tree = db.module_tree(self.id.package);
+        let parent_id = module_tree[self.id.local_id].parent?;
+        Some(Module {
+            id: ModuleId {
+                package: self.id.package,
+                local_id: parent_id,
+            },
+        })
+    }
+
+    /// Returns the name of this module or None if this is the root module
+    pub fn name(self, db: &dyn HirDatabase) -> Option<Name> {
+        let module_tree = db.module_tree(self.id.package);
+        let parent = module_tree[self.id.local_id].parent?;
+        module_tree[parent]
+            .children
+            .iter()
+            .find_map(|(name, module_id)| {
+                if *module_id == self.id.local_id {
+                    Some(name.clone())
+                } else {
+                    None
+                }
+            })
+    }
+
+    /// Returns all the child modules of this module
+    pub fn children(self, db: &dyn HirDatabase) -> Vec<Module> {
+        let module_tree = db.module_tree(self.id.package);
+        module_tree[self.id.local_id]
+            .children
+            .iter()
+            .map(|(_, local_id)| Module {
+                id: ModuleId {
+                    package: self.id.package,
+                    local_id: *local_id,
+                },
+            })
+            .collect()
+    }
+
     /// Returns the file that defines the module
     pub fn file_id(self, db: &dyn HirDatabase) -> Option<FileId> {
         db.module_tree(self.id.package).modules[self.id.local_id].file
@@ -39,12 +82,19 @@ impl Module {
 
     /// Iterate over all diagnostics from this `Module` by placing them in the `sink`
     pub fn diagnostics(self, db: &dyn HirDatabase, sink: &mut DiagnosticSink) {
+        // Add diagnostics from the package definitions
+        let package_defs = db.package_defs(self.id.package);
+        package_defs.add_diagnostics(db.upcast(), self.id.local_id, sink);
+
+        // Add diagnostics from the item tree
         if let Some(file_id) = self.file_id(db) {
             let item_tree = db.item_tree(file_id);
             for diagnostics in item_tree.diagnostics.iter() {
                 diagnostics.add_to(db, &*item_tree, sink);
             }
         }
+
+        // Add diagnostics from the items
         for decl in self.declarations(db) {
             match decl {
                 ModuleDef::Function(f) => f.diagnostics(db, sink),
@@ -54,6 +104,17 @@ impl Module {
             }
         }
     }
+
+    /// Returns the path from this module to the root module
+    pub fn path_to_root(self, db: &dyn HirDatabase) -> Vec<Module> {
+        let mut res = vec![self];
+        let mut curr = self;
+        while let Some(next) = curr.parent(db) {
+            res.push(next);
+            curr = next
+        }
+        res
+    }
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]

crates/mun_hir/src/diagnostics.rs

@@ -746,3 +746,41 @@ impl Diagnostic for FreeTypeAliasWithoutTypeRef {
         self
     }
 }
+
+#[derive(Debug)]
+pub struct UnresolvedImport {
+    pub use_tree: InFile<AstPtr<ast::UseTree>>,
+}
+
+impl Diagnostic for UnresolvedImport {
+    fn message(&self) -> String {
+        "unresolved import".to_string()
+    }
+
+    fn source(&self) -> InFile<SyntaxNodePtr> {
+        self.use_tree.map(Into::into)
+    }
+
+    fn as_any(&self) -> &(dyn Any + Send) {
+        self
+    }
+}
+
+#[derive(Debug)]
+pub struct ImportDuplicateDefinition {
+    pub use_tree: InFile<AstPtr<ast::UseTree>>,
+}
+
+impl Diagnostic for ImportDuplicateDefinition {
+    fn message(&self) -> String {
+        "a second item with the same name imported. Try to use an alias.".to_string()
+    }
+
+    fn source(&self) -> InFile<SyntaxNodePtr> {
+        self.use_tree.map(Into::into)
+    }
+
+    fn as_any(&self) -> &(dyn Any + Send) {
+        self
+    }
+}

crates/mun_hir/src/item_scope.rs

@@ -1,7 +1,32 @@
+use crate::module_tree::LocalModuleId;
 use crate::primitive_type::PrimitiveType;
 use crate::{ids::ItemDefinitionId, visibility::Visibility, Name, PerNs};
 use once_cell::sync::Lazy;
-use rustc_hash::FxHashMap;
+use rustc_hash::{FxHashMap, FxHashSet};
+use std::collections::hash_map::Entry;
+
+/// Defines the type of import. An import can either be a named import (e.g. `use foo::Bar`) or a
+/// wildcard import (e.g. `use foo::*`)
+#[derive(Copy, Clone)]
+pub(crate) enum ImportType {
+    /// A wildcard import statement (`use foo::*`)
+    Glob,
+
+    /// A named import statement (`use foo::Bar`)
+    Named,
+}
+
+/// A struct that holds information on which name was imported via a glob import. This information
+/// is used by the `PackageDef` collector to keep track of duplicates so that this doesn't result in
+/// a duplicate name error; e.g. :
+/// ```mun
+/// use foo::{Foo, *};
+/// ```
+#[derive(Debug, Default)]
+pub struct PerNsGlobImports {
+    types: FxHashSet<(LocalModuleId, Name)>,
+    values: FxHashSet<(LocalModuleId, Name)>,
+}
 
 /// Holds all items that are visible from an item as well as by which name and under which
 /// visibility they are accessible.
@@ -17,6 +42,16 @@ pub struct ItemScope {
     defs: Vec<ItemDefinitionId>,
 }
 
+/// A struct that is returned from `add_resolution_from_import`.
+#[derive(Debug)]
+pub(crate) struct AddResolutionFromImportResult {
+    /// Whether or not adding the resolution changed the item scope
+    pub changed: bool,
+
+    /// Whether or not adding the resolution will overwrite an existing entry
+    pub duplicate: bool,
+}
+
 pub(crate) static BUILTIN_SCOPE: Lazy<FxHashMap<Name, PerNs<(ItemDefinitionId, Visibility)>>> =
     Lazy::new(|| {
         PrimitiveType::ALL
@@ -31,6 +66,14 @@ pub(crate) static BUILTIN_SCOPE: Lazy<FxHashMap<Name, PerNs<(ItemDefinitionId, V
     });
 
 impl ItemScope {
+    /// Returns all the entries in the scope
+    pub fn entries(
+        &self,
+    ) -> impl Iterator<Item = (&'_ Name, PerNs<(ItemDefinitionId, Visibility)>)> + '_ {
+        let keys: FxHashSet<_> = self.types.keys().chain(self.values.keys()).collect();
+        keys.into_iter().map(move |name| (name, self.get(name)))
+    }
+
     /// Returns an iterator over all declarations with this scope
     pub fn declarations(&self) -> impl Iterator<Item = ItemDefinitionId> + '_ {
         self.defs.iter().copied()
@@ -41,18 +84,110 @@ impl ItemScope {
         self.defs.push(def)
     }
 
-    /// Adds a named item resolution into the scope
+    /// Adds a named item resolution into the scope. Returns true if adding the resolution changes
+    /// the scope.
     pub(crate) fn add_resolution(
         &mut self,
         name: Name,
         def: PerNs<(ItemDefinitionId, Visibility)>,
-    ) {
+    ) -> bool {
+        let mut changed = false;
         if let Some((types, visibility)) = def.types {
-            self.types.insert(name.clone(), (types, visibility));
+            self.types.entry(name.clone()).or_insert_with(|| {
+                changed = true;
+                (types, visibility)
+            });
         }
         if let Some((values, visibility)) = def.values {
-            self.values.insert(name, (values, visibility));
+            self.values.entry(name).or_insert_with(|| {
+                changed = true;
+                (values, visibility)
+            });
         }
+
+        changed
+    }
+
+    /// Adds a named item resolution into the scope which is the result of a `use` statement.
+    /// Returns true if adding the resolution changes the scope.
+    pub(crate) fn add_resolution_from_import(
+        &mut self,
+        glob_imports: &mut PerNsGlobImports,
+        lookup: (LocalModuleId, Name),
+        def: PerNs<(ItemDefinitionId, Visibility)>,
+        def_import_type: ImportType,
+    ) -> AddResolutionFromImportResult {
+        let mut changed = false;
+        let mut duplicate = false;
+
+        macro_rules! check_changed {
+            (
+                $changed:ident,
+                ( $this:ident / $def:ident ) . $field:ident,
+                $glob_imports:ident [ $lookup:ident ],
+                $def_import_type:ident
+            ) => {{
+                let existing = $this.$field.entry($lookup.1.clone());
+                match (existing, $def.$field) {
+                    // The name doesnt exist yet in the scope
+                    (Entry::Vacant(entry), Some(_)) => {
+                        match $def_import_type {
+                            // If this is a wildcard import, add it to the list of items we imported
+                            // via a glob. This information is stored so if we later explicitly
+                            // import this type or value, it doesn't cause a conflict.
+                            ImportType::Glob => {
+                                $glob_imports.$field.insert($lookup.clone());
+                            }
+                            // If this is *not* a wildcard import, remove it from the list of items
+                            // imported via a glob.
+                            ImportType::Named => {
+                                $glob_imports.$field.remove(&$lookup);
+                            }
+                        }
+
+                        if let Some(fld) = $def.$field {
+                            entry.insert(fld);
+                        }
+                        $changed = true;
+                    }
+                    // If there is already an entry for this resolution, but it came from a glob
+                    // pattern, overwrite it and mark it as not included from the glob pattern.
+                    (Entry::Occupied(mut entry), Some(_))
+                        if $glob_imports.$field.contains(&$lookup)
+                            && matches!($def_import_type, ImportType::Named) =>
+                    {
+                        $glob_imports.$field.remove(&$lookup);
+                        if let Some(fld) = $def.$field {
+                            entry.insert(fld);
+                        }
+                        $changed = true;
+                    }
+                    (Entry::Occupied(_), Some(_)) => {
+                        let is_previous_from_glob = $glob_imports.$field.contains(&$lookup);
+                        let is_explicit_import = matches!($def_import_type, ImportType::Named);
+                        if is_explicit_import && !is_previous_from_glob {
+                            duplicate = true;
+                        }
+                    }
+                    _ => {}
+                }
+            }};
+        }
+
+        check_changed!(
+            changed,
+            (self / def).types,
+            glob_imports[lookup],
+            def_import_type
+        );
+        check_changed!(
+            changed,
+            (self / def).values,
+            glob_imports[lookup],
+            def_import_type
+        );
+
+        AddResolutionFromImportResult { changed, duplicate }
     }
 
     /// Gets a name from the current module scope