use ra_db::{SyntaxDatabase}; use ra_syntax::{ AstNode, SyntaxNode, TreeArc, ast::self, algo::{find_covering_node, find_node_at_offset, find_leaf_at_offset, visit::{visitor, Visitor}}, }; use crate::{db::RootDatabase, RangeInfo, FilePosition, FileRange, NavigationTarget}; pub(crate) fn hover(db: &RootDatabase, position: FilePosition) -> Option> { let file = db.source_file(position.file_id); let mut res = Vec::new(); let mut range = None; if let Some(name_ref) = find_node_at_offset::(file.syntax(), position.offset) { use crate::goto_definition::{ReferenceResult::*, reference_definition}; let ref_result = reference_definition(db, position.file_id, name_ref); match ref_result { Exact(nav) => res.extend(doc_text_for(db, nav)), Approximate(navs) => { let mut msg = String::from("Failed to exactly resolve the symbol. This is probably because rust_analyzer does not yet support glob imports or traits."); if !navs.is_empty() { msg.push_str(" \nThese items were found instead:"); } res.push(msg); for nav in navs { res.extend(doc_text_for(db, nav)) } } } if !res.is_empty() { range = Some(name_ref.syntax().range()) } } if range.is_none() { let node = find_leaf_at_offset(file.syntax(), position.offset).find_map(|leaf| { leaf.ancestors() .find(|n| ast::Expr::cast(*n).is_some() || ast::Pat::cast(*n).is_some()) })?; let frange = FileRange { file_id: position.file_id, range: node.range(), }; res.extend(type_of(db, frange).map(Into::into)); range = Some(node.range()); }; let range = range?; if res.is_empty() { return None; } let res = RangeInfo::new(range, res.join("\n\n---\n")); Some(res) } pub(crate) fn type_of(db: &RootDatabase, frange: FileRange) -> Option { let file = db.source_file(frange.file_id); let syntax = file.syntax(); let leaf_node = find_covering_node(syntax, frange.range); // if we picked identifier, expand to pattern/expression let node = leaf_node .ancestors() .take_while(|it| it.range() == leaf_node.range()) .find(|&it| ast::Expr::cast(it).is_some() || ast::Pat::cast(it).is_some()) .unwrap_or(leaf_node); let parent_fn = node.ancestors().find_map(ast::FnDef::cast)?; let function = hir::source_binder::function_from_source(db, frange.file_id, parent_fn)?; let infer = function.infer(db); let syntax_mapping = function.body_syntax_mapping(db); if let Some(expr) = ast::Expr::cast(node).and_then(|e| syntax_mapping.node_expr(e)) { Some(infer[expr].to_string()) } else if let Some(pat) = ast::Pat::cast(node).and_then(|p| syntax_mapping.node_pat(p)) { Some(infer[pat].to_string()) } else { None } } // FIXME: this should not really use navigation target. Rather, approximatelly // resovled symbol should return a `DefId`. fn doc_text_for(db: &RootDatabase, nav: NavigationTarget) -> Option { match (nav.description(db), nav.docs(db)) { (Some(desc), Some(docs)) => Some("```rust\n".to_string() + &*desc + "\n```\n\n" + &*docs), (Some(desc), None) => Some("```rust\n".to_string() + &*desc + "\n```"), (None, Some(docs)) => Some(docs), _ => None, } } impl NavigationTarget { fn node(&self, db: &RootDatabase) -> Option> { let source_file = db.source_file(self.file_id()); let source_file = source_file.syntax(); let node = source_file .descendants() .find(|node| node.kind() == self.kind() && node.range() == self.full_range())? .to_owned(); Some(node) } fn docs(&self, db: &RootDatabase) -> Option { let node = self.node(db)?; fn doc_comments(node: &N) -> Option { let comments = node.doc_comment_text(); if comments.is_empty() { None } else { Some(comments) } } visitor() .visit(doc_comments::) .visit(doc_comments::) .visit(doc_comments::) .visit(doc_comments::) .visit(doc_comments::) .visit(doc_comments::) .visit(doc_comments::) .visit(doc_comments::) .accept(&node)? } /// Get a description of this node. /// /// e.g. `struct Name`, `enum Name`, `fn Name` fn description(&self, db: &RootDatabase) -> Option { // TODO: After type inference is done, add type information to improve the output let node = self.node(db)?; fn visit_node(node: &T, label: &str) -> Option where T: ast::NameOwner + ast::VisibilityOwner, { let mut string = node .visibility() .map(|v| format!("{} ", v.syntax().text())) .unwrap_or_default(); string.push_str(label); node.name()?.syntax().text().push_to(&mut string); Some(string) } visitor() .visit(|node: &ast::FnDef| visit_node(node, "fn ")) .visit(|node: &ast::StructDef| visit_node(node, "struct ")) .visit(|node: &ast::EnumDef| visit_node(node, "enum ")) .visit(|node: &ast::TraitDef| visit_node(node, "trait ")) .visit(|node: &ast::Module| visit_node(node, "mod ")) .visit(|node: &ast::TypeDef| visit_node(node, "type ")) .visit(|node: &ast::ConstDef| visit_node(node, "const ")) .visit(|node: &ast::StaticDef| visit_node(node, "static ")) .accept(&node)? } } #[cfg(test)] mod tests { use ra_syntax::TextRange; use crate::mock_analysis::{single_file_with_position, single_file_with_range}; #[test] fn hover_shows_type_of_an_expression() { let (analysis, position) = single_file_with_position( " pub fn foo() -> u32 { 1 } fn main() { let foo_test = foo()<|>; } ", ); let hover = analysis.hover(position).unwrap().unwrap(); assert_eq!(hover.range, TextRange::from_to(95.into(), 100.into())); assert_eq!(hover.info, "u32"); } #[test] fn hover_for_local_variable() { let (analysis, position) = single_file_with_position("fn func(foo: i32) { fo<|>o; }"); let hover = analysis.hover(position).unwrap().unwrap(); assert_eq!(hover.info, "i32"); } #[test] fn hover_for_local_variable_pat() { let (analysis, position) = single_file_with_position("fn func(fo<|>o: i32) {}"); let hover = analysis.hover(position).unwrap().unwrap(); assert_eq!(hover.info, "i32"); } #[test] fn test_type_of_for_function() { let (analysis, range) = single_file_with_range( " pub fn foo() -> u32 { 1 }; fn main() { let foo_test = <|>foo()<|>; } ", ); let type_name = analysis.type_of(range).unwrap().unwrap(); assert_eq!("u32", &type_name); } // FIXME: improve type_of to make this work #[test] fn test_type_of_for_expr_1() { let (analysis, range) = single_file_with_range( " fn main() { let foo = <|>1 + foo_test<|>; } ", ); let type_name = analysis.type_of(range).unwrap().unwrap(); assert_eq!("[unknown]", &type_name); } #[test] fn test_type_of_for_expr_2() { let (analysis, range) = single_file_with_range( " fn main() { let foo: usize = 1; let bar = <|>1 + foo<|>; } ", ); let type_name = analysis.type_of(range).unwrap().unwrap(); assert_eq!("usize", &type_name); } }