1 files changed, 546 insertions, 0 deletions

diff --git a/crates/ra_hir/src/source_analyzer.rs b/crates/ra_hir/src/source_analyzer.rs
new file mode 100644
index 000000000..3df48842d
--- /dev/null
+++ b/crates/ra_hir/src/source_analyzer.rs
@@ -0,0 +1,546 @@
+//! Lookup hir elements using positions in the source code. This is a lossy
+//! transformation: in general, a single source might correspond to several
+//! modules, functions, etc, due to macros, cfgs and `#[path=]` attributes on
+//! modules.
+//!
+//! So, this modules should not be used during hir construction, it exists
+//! purely for "IDE needs".
+use std::sync::Arc;
+
+use either::Either;
+use hir_def::{
+    body::{
+        scope::{ExprScopes, ScopeId},
+        BodySourceMap,
+    },
+    expr::{ExprId, PatId},
+    nameres::ModuleSource,
+    resolver::{self, resolver_for_scope, HasResolver, Resolver, TypeNs, ValueNs},
+    AssocItemId, DefWithBodyId,
+};
+use hir_expand::{
+    hygiene::Hygiene, name::AsName, AstId, HirFileId, InFile, MacroCallId, MacroCallKind,
+};
+use hir_ty::{method_resolution, Canonical, InEnvironment, InferenceResult, TraitEnvironment, Ty};
+use ra_prof::profile;
+use ra_syntax::{
+    ast::{self, AstNode},
+    match_ast, AstPtr,
+    SyntaxKind::*,
+    SyntaxNode, SyntaxNodePtr, SyntaxToken, TextRange, TextUnit,
+};
+
+use crate::{
+    db::HirDatabase, Adt, AssocItem, Const, DefWithBody, Enum, EnumVariant, FromSource, Function,
+    ImplBlock, Local, MacroDef, Name, Path, ScopeDef, Static, Struct, Trait, Type, TypeAlias,
+    TypeParam,
+};
+
+/// `SourceAnalyzer` is a convenience wrapper which exposes HIR API in terms of
+/// original source files. It should not be used inside the HIR itself.
+#[derive(Debug)]
+pub struct SourceAnalyzer {
+    file_id: HirFileId,
+    resolver: Resolver,
+    body_owner: Option<DefWithBody>,
+    body_source_map: Option<Arc<BodySourceMap>>,
+    infer: Option<Arc<InferenceResult>>,
+    scopes: Option<Arc<ExprScopes>>,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum PathResolution {
+    /// An item
+    Def(crate::ModuleDef),
+    /// A local binding (only value namespace)
+    Local(Local),
+    /// A generic parameter
+    TypeParam(TypeParam),
+    SelfType(crate::ImplBlock),
+    Macro(MacroDef),
+    AssocItem(crate::AssocItem),
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct ScopeEntryWithSyntax {
+    pub(crate) name: Name,
+    pub(crate) ptr: Either<AstPtr<ast::Pat>, AstPtr<ast::SelfParam>>,
+}
+
+impl ScopeEntryWithSyntax {
+    pub fn name(&self) -> &Name {
+        &self.name
+    }
+
+    pub fn ptr(&self) -> Either<AstPtr<ast::Pat>, AstPtr<ast::SelfParam>> {
+        self.ptr
+    }
+}
+
+#[derive(Debug)]
+pub struct ReferenceDescriptor {
+    pub range: TextRange,
+    pub name: String,
+}
+
+#[derive(Debug)]
+pub struct Expansion {
+    macro_call_id: MacroCallId,
+}
+
+impl Expansion {
+    pub fn map_token_down(
+        &self,
+        db: &impl HirDatabase,
+        token: InFile<&SyntaxToken>,
+    ) -> Option<InFile<SyntaxToken>> {
+        let exp_info = self.file_id().expansion_info(db)?;
+        exp_info.map_token_down(token)
+    }
+
+    pub fn file_id(&self) -> HirFileId {
+        self.macro_call_id.as_file()
+    }
+}
+
+impl SourceAnalyzer {
+    pub fn new(
+        db: &impl HirDatabase,
+        node: InFile<&SyntaxNode>,
+        offset: Option<TextUnit>,
+    ) -> SourceAnalyzer {
+        let _p = profile("SourceAnalyzer::new");
+        let def_with_body = def_with_body_from_child_node(db, node);
+        if let Some(def) = def_with_body {
+            let (_body, source_map) = db.body_with_source_map(def.into());
+            let scopes = db.expr_scopes(def.into());
+            let scope = match offset {
+                None => scope_for(&scopes, &source_map, node),
+                Some(offset) => scope_for_offset(&scopes, &source_map, node.with_value(offset)),
+            };
+            let resolver = resolver_for_scope(db, def.into(), scope);
+            SourceAnalyzer {
+                resolver,
+                body_owner: Some(def),
+                body_source_map: Some(source_map),
+                infer: Some(db.infer(def.into())),
+                scopes: Some(scopes),
+                file_id: node.file_id,
+            }
+        } else {
+            SourceAnalyzer {
+                resolver: node
+                    .value
+                    .ancestors()
+                    .find_map(|it| try_get_resolver_for_node(db, node.with_value(&it)))
+                    .unwrap_or_default(),
+                body_owner: None,
+                body_source_map: None,
+                infer: None,
+                scopes: None,
+                file_id: node.file_id,
+            }
+        }
+    }
+
+    pub fn module(&self) -> Option<crate::code_model::Module> {
+        Some(crate::code_model::Module { id: self.resolver.module()? })
+    }
+
+    fn expr_id(&self, expr: &ast::Expr) -> Option<ExprId> {
+        let src = InFile { file_id: self.file_id, value: expr };
+        self.body_source_map.as_ref()?.node_expr(src)
+    }
+
+    fn pat_id(&self, pat: &ast::Pat) -> Option<PatId> {
+        let src = InFile { file_id: self.file_id, value: pat };
+        self.body_source_map.as_ref()?.node_pat(src)
+    }
+
+    fn expand_expr(
+        &self,
+        db: &impl HirDatabase,
+        expr: InFile<&ast::Expr>,
+    ) -> Option<InFile<ast::Expr>> {
+        let macro_call = ast::MacroCall::cast(expr.value.syntax().clone())?;
+        let macro_file =
+            self.body_source_map.as_ref()?.node_macro_file(expr.with_value(&macro_call))?;
+        let expanded = db.parse_or_expand(macro_file)?;
+        let kind = expanded.kind();
+        let expr = InFile::new(macro_file, ast::Expr::cast(expanded)?);
+
+        if ast::MacroCall::can_cast(kind) {
+            self.expand_expr(db, expr.as_ref())
+        } else {
+            Some(expr)
+        }
+    }
+
+    pub fn type_of(&self, db: &impl HirDatabase, expr: &ast::Expr) -> Option<Type> {
+        let expr_id = if let Some(expr) = self.expand_expr(db, InFile::new(self.file_id, expr)) {
+            self.body_source_map.as_ref()?.node_expr(expr.as_ref())?
+        } else {
+            self.expr_id(expr)?
+        };
+
+        let ty = self.infer.as_ref()?[expr_id].clone();
+        let environment = TraitEnvironment::lower(db, &self.resolver);
+        Some(Type { krate: self.resolver.krate()?, ty: InEnvironment { value: ty, environment } })
+    }
+
+    pub fn type_of_pat(&self, db: &impl HirDatabase, pat: &ast::Pat) -> Option<Type> {
+        let pat_id = self.pat_id(pat)?;
+        let ty = self.infer.as_ref()?[pat_id].clone();
+        let environment = TraitEnvironment::lower(db, &self.resolver);
+        Some(Type { krate: self.resolver.krate()?, ty: InEnvironment { value: ty, environment } })
+    }
+
+    pub fn resolve_method_call(&self, call: &ast::MethodCallExpr) -> Option<Function> {
+        let expr_id = self.expr_id(&call.clone().into())?;
+        self.infer.as_ref()?.method_resolution(expr_id).map(Function::from)
+    }
+
+    pub fn resolve_field(&self, field: &ast::FieldExpr) -> Option<crate::StructField> {
+        let expr_id = self.expr_id(&field.clone().into())?;
+        self.infer.as_ref()?.field_resolution(expr_id).map(|it| it.into())
+    }
+
+    pub fn resolve_record_field(&self, field: &ast::RecordField) -> Option<crate::StructField> {
+        let expr_id = match field.expr() {
+            Some(it) => self.expr_id(&it)?,
+            None => {
+                let src = InFile { file_id: self.file_id, value: field };
+                self.body_source_map.as_ref()?.field_init_shorthand_expr(src)?
+            }
+        };
+        self.infer.as_ref()?.record_field_resolution(expr_id).map(|it| it.into())
+    }
+
+    pub fn resolve_record_literal(&self, record_lit: &ast::RecordLit) -> Option<crate::VariantDef> {
+        let expr_id = self.expr_id(&record_lit.clone().into())?;
+        self.infer.as_ref()?.variant_resolution_for_expr(expr_id).map(|it| it.into())
+    }
+
+    pub fn resolve_record_pattern(&self, record_pat: &ast::RecordPat) -> Option<crate::VariantDef> {
+        let pat_id = self.pat_id(&record_pat.clone().into())?;
+        self.infer.as_ref()?.variant_resolution_for_pat(pat_id).map(|it| it.into())
+    }
+
+    pub fn resolve_macro_call(
+        &self,
+        db: &impl HirDatabase,
+        macro_call: InFile<&ast::MacroCall>,
+    ) -> Option<MacroDef> {
+        let hygiene = Hygiene::new(db, macro_call.file_id);
+        let path = macro_call.value.path().and_then(|ast| Path::from_src(ast, &hygiene))?;
+        self.resolver.resolve_path_as_macro(db, path.mod_path()).map(|it| it.into())
+    }
+
+    pub fn resolve_hir_path(
+        &self,
+        db: &impl HirDatabase,
+        path: &crate::Path,
+    ) -> Option<PathResolution> {
+        let types =
+            self.resolver.resolve_path_in_type_ns_fully(db, path.mod_path()).map(|ty| match ty {
+                TypeNs::SelfType(it) => PathResolution::SelfType(it.into()),
+                TypeNs::GenericParam(id) => PathResolution::TypeParam(TypeParam { id }),
+                TypeNs::AdtSelfType(it) | TypeNs::AdtId(it) => {
+                    PathResolution::Def(Adt::from(it).into())
+                }
+                TypeNs::EnumVariantId(it) => PathResolution::Def(EnumVariant::from(it).into()),
+                TypeNs::TypeAliasId(it) => PathResolution::Def(TypeAlias::from(it).into()),
+                TypeNs::BuiltinType(it) => PathResolution::Def(it.into()),
+                TypeNs::TraitId(it) => PathResolution::Def(Trait::from(it).into()),
+            });
+        let values =
+            self.resolver.resolve_path_in_value_ns_fully(db, path.mod_path()).and_then(|val| {
+                let res = match val {
+                    ValueNs::LocalBinding(pat_id) => {
+                        let var = Local { parent: self.body_owner?, pat_id };
+                        PathResolution::Local(var)
+                    }
+                    ValueNs::FunctionId(it) => PathResolution::Def(Function::from(it).into()),
+                    ValueNs::ConstId(it) => PathResolution::Def(Const::from(it).into()),
+                    ValueNs::StaticId(it) => PathResolution::Def(Static::from(it).into()),
+                    ValueNs::StructId(it) => PathResolution::Def(Struct::from(it).into()),
+                    ValueNs::EnumVariantId(it) => PathResolution::Def(EnumVariant::from(it).into()),
+                };
+                Some(res)
+            });
+
+        let items = self
+            .resolver
+            .resolve_module_path_in_items(db, path.mod_path())
+            .take_types()
+            .map(|it| PathResolution::Def(it.into()));
+        types.or(values).or(items).or_else(|| {
+            self.resolver
+                .resolve_path_as_macro(db, path.mod_path())
+                .map(|def| PathResolution::Macro(def.into()))
+        })
+    }
+
+    pub fn resolve_path(&self, db: &impl HirDatabase, path: &ast::Path) -> Option<PathResolution> {
+        if let Some(path_expr) = path.syntax().parent().and_then(ast::PathExpr::cast) {
+            let expr_id = self.expr_id(&path_expr.into())?;
+            if let Some(assoc) = self.infer.as_ref()?.assoc_resolutions_for_expr(expr_id) {
+                return Some(PathResolution::AssocItem(assoc.into()));
+            }
+        }
+        if let Some(path_pat) = path.syntax().parent().and_then(ast::PathPat::cast) {
+            let pat_id = self.pat_id(&path_pat.into())?;
+            if let Some(assoc) = self.infer.as_ref()?.assoc_resolutions_for_pat(pat_id) {
+                return Some(PathResolution::AssocItem(assoc.into()));
+            }
+        }
+        // This must be a normal source file rather than macro file.
+        let hir_path = crate::Path::from_ast(path.clone())?;
+        self.resolve_hir_path(db, &hir_path)
+    }
+
+    fn resolve_local_name(&self, name_ref: &ast::NameRef) -> Option<ScopeEntryWithSyntax> {
+        let name = name_ref.as_name();
+        let source_map = self.body_source_map.as_ref()?;
+        let scopes = self.scopes.as_ref()?;
+        let scope = scope_for(scopes, source_map, InFile::new(self.file_id, name_ref.syntax()))?;
+        let entry = scopes.resolve_name_in_scope(scope, &name)?;
+        Some(ScopeEntryWithSyntax {
+            name: entry.name().clone(),
+            ptr: source_map.pat_syntax(entry.pat())?.value,
+        })
+    }
+
+    pub fn process_all_names(&self, db: &impl HirDatabase, f: &mut dyn FnMut(Name, ScopeDef)) {
+        self.resolver.process_all_names(db, &mut |name, def| {
+            let def = match def {
+                resolver::ScopeDef::PerNs(it) => it.into(),
+                resolver::ScopeDef::ImplSelfType(it) => ScopeDef::ImplSelfType(it.into()),
+                resolver::ScopeDef::AdtSelfType(it) => ScopeDef::AdtSelfType(it.into()),
+                resolver::ScopeDef::GenericParam(id) => ScopeDef::GenericParam(TypeParam { id }),
+                resolver::ScopeDef::Local(pat_id) => {
+                    let parent = self.resolver.body_owner().unwrap().into();
+                    ScopeDef::Local(Local { parent, pat_id })
+                }
+            };
+            f(name, def)
+        })
+    }
+
+    // FIXME: we only use this in `inline_local_variable` assist, ideally, we
+    // should switch to general reference search infra there.
+    pub fn find_all_refs(&self, pat: &ast::BindPat) -> Vec<ReferenceDescriptor> {
+        let fn_def = pat.syntax().ancestors().find_map(ast::FnDef::cast).unwrap();
+        let ptr = Either::Left(AstPtr::new(&ast::Pat::from(pat.clone())));
+        fn_def
+            .syntax()
+            .descendants()
+            .filter_map(ast::NameRef::cast)
+            .filter(|name_ref| match self.resolve_local_name(&name_ref) {
+                None => false,
+                Some(entry) => entry.ptr() == ptr,
+            })
+            .map(|name_ref| ReferenceDescriptor {
+                name: name_ref.text().to_string(),
+                range: name_ref.syntax().text_range(),
+            })
+            .collect()
+    }
+
+    pub fn iterate_method_candidates<T>(
+        &self,
+        db: &impl HirDatabase,
+        ty: &Type,
+        name: Option<&Name>,
+        mut callback: impl FnMut(&Ty, Function) -> Option<T>,
+    ) -> Option<T> {
+        // There should be no inference vars in types passed here
+        // FIXME check that?
+        // FIXME replace Unknown by bound vars here
+        let canonical = Canonical { value: ty.ty.value.clone(), num_vars: 0 };
+        method_resolution::iterate_method_candidates(
+            &canonical,
+            db,
+            &self.resolver,
+            name,
+            method_resolution::LookupMode::MethodCall,
+            |ty, it| match it {
+                AssocItemId::FunctionId(f) => callback(ty, f.into()),
+                _ => None,
+            },
+        )
+    }
+
+    pub fn iterate_path_candidates<T>(
+        &self,
+        db: &impl HirDatabase,
+        ty: &Type,
+        name: Option<&Name>,
+        mut callback: impl FnMut(&Ty, AssocItem) -> Option<T>,
+    ) -> Option<T> {
+        // There should be no inference vars in types passed here
+        // FIXME check that?
+        // FIXME replace Unknown by bound vars here
+        let canonical = Canonical { value: ty.ty.value.clone(), num_vars: 0 };
+        method_resolution::iterate_method_candidates(
+            &canonical,
+            db,
+            &self.resolver,
+            name,
+            method_resolution::LookupMode::Path,
+            |ty, it| callback(ty, it.into()),
+        )
+    }
+
+    pub fn expand(
+        &self,
+        db: &impl HirDatabase,
+        macro_call: InFile<&ast::MacroCall>,
+    ) -> Option<Expansion> {
+        let def = self.resolve_macro_call(db, macro_call)?.id;
+        let ast_id = AstId::new(
+            macro_call.file_id,
+            db.ast_id_map(macro_call.file_id).ast_id(macro_call.value),
+        );
+        Some(Expansion { macro_call_id: def.as_call_id(db, MacroCallKind::FnLike(ast_id)) })
+    }
+}
+
+fn try_get_resolver_for_node(db: &impl HirDatabase, node: InFile<&SyntaxNode>) -> Option<Resolver> {
+    match_ast! {
+        match (node.value) {
+            ast::Module(it) => {
+                let src = node.with_value(it);
+                Some(crate::Module::from_declaration(db, src)?.id.resolver(db))
+            },
+             ast::SourceFile(it) => {
+                let src = node.with_value(ModuleSource::SourceFile(it));
+                Some(crate::Module::from_definition(db, src)?.id.resolver(db))
+            },
+            ast::StructDef(it) => {
+                let src = node.with_value(it);
+                Some(Struct::from_source(db, src)?.id.resolver(db))
+            },
+            ast::EnumDef(it) => {
+                let src = node.with_value(it);
+                Some(Enum::from_source(db, src)?.id.resolver(db))
+            },
+            ast::ImplBlock(it) => {
+                let src = node.with_value(it);
+                Some(ImplBlock::from_source(db, src)?.id.resolver(db))
+            },
+            ast::TraitDef(it) => {
+                let src = node.with_value(it);
+                Some(Trait::from_source(db, src)?.id.resolver(db))
+            },
+            _ => match node.value.kind() {
+                FN_DEF | CONST_DEF | STATIC_DEF => {
+                    let def = def_with_body_from_child_node(db, node)?;
+                    let def = DefWithBodyId::from(def);
+                    Some(def.resolver(db))
+                }
+                // FIXME add missing cases
+                _ => None
+            }
+        }
+    }
+}
+
+fn def_with_body_from_child_node(
+    db: &impl HirDatabase,
+    child: InFile<&SyntaxNode>,
+) -> Option<DefWithBody> {
+    let _p = profile("def_with_body_from_child_node");
+    child.cloned().ancestors_with_macros(db).find_map(|node| {
+        let n = &node.value;
+        match_ast! {
+            match n {
+                ast::FnDef(def)  => { return Function::from_source(db, node.with_value(def)).map(DefWithBody::from); },
+                ast::ConstDef(def) => { return Const::from_source(db, node.with_value(def)).map(DefWithBody::from); },
+                ast::StaticDef(def) => { return Static::from_source(db, node.with_value(def)).map(DefWithBody::from); },
+                _ => { None },
+            }
+        }
+    })
+}
+
+fn scope_for(
+    scopes: &ExprScopes,
+    source_map: &BodySourceMap,
+    node: InFile<&SyntaxNode>,
+) -> Option<ScopeId> {
+    node.value
+        .ancestors()
+        .filter_map(ast::Expr::cast)
+        .filter_map(|it| source_map.node_expr(InFile::new(node.file_id, &it)))
+        .find_map(|it| scopes.scope_for(it))
+}
+
+fn scope_for_offset(
+    scopes: &ExprScopes,
+    source_map: &BodySourceMap,
+    offset: InFile<TextUnit>,
+) -> Option<ScopeId> {
+    scopes
+        .scope_by_expr()
+        .iter()
+        .filter_map(|(id, scope)| {
+            let source = source_map.expr_syntax(*id)?;
+            // FIXME: correctly handle macro expansion
+            if source.file_id != offset.file_id {
+                return None;
+            }
+            let syntax_node_ptr =
+                source.value.either(|it| it.syntax_node_ptr(), |it| it.syntax_node_ptr());
+            Some((syntax_node_ptr, scope))
+        })
+        // find containing scope
+        .min_by_key(|(ptr, _scope)| {
+            (
+                !(ptr.range().start() <= offset.value && offset.value <= ptr.range().end()),
+                ptr.range().len(),
+            )
+        })
+        .map(|(ptr, scope)| {
+            adjust(scopes, source_map, ptr, offset.file_id, offset.value).unwrap_or(*scope)
+        })
+}
+
+// XXX: during completion, cursor might be outside of any particular
+// expression. Try to figure out the correct scope...
+fn adjust(
+    scopes: &ExprScopes,
+    source_map: &BodySourceMap,
+    ptr: SyntaxNodePtr,
+    file_id: HirFileId,
+    offset: TextUnit,
+) -> Option<ScopeId> {
+    let r = ptr.range();
+    let child_scopes = scopes
+        .scope_by_expr()
+        .iter()
+        .filter_map(|(id, scope)| {
+            let source = source_map.expr_syntax(*id)?;
+            // FIXME: correctly handle macro expansion
+            if source.file_id != file_id {
+                return None;
+            }
+            let syntax_node_ptr =
+                source.value.either(|it| it.syntax_node_ptr(), |it| it.syntax_node_ptr());
+            Some((syntax_node_ptr, scope))
+        })
+        .map(|(ptr, scope)| (ptr.range(), scope))
+        .filter(|(range, _)| range.start() <= offset && range.is_subrange(&r) && *range != r);
+
+    child_scopes
+        .max_by(|(r1, _), (r2, _)| {
+            if r2.is_subrange(&r1) {
+                std::cmp::Ordering::Greater
+            } else if r1.is_subrange(&r2) {
+                std::cmp::Ordering::Less
+            } else {
+                r1.start().cmp(&r2.start())
+            }
+        })
+        .map(|(_ptr, scope)| *scope)
+}