Try to complete within macros

Author: flodiebold

Cargo.lock

@@ -12,6 +12,8 @@ log = "0.4.8"
 rustc-hash = "1.1.0"
 either = "1.5.3"
 
+itertools = "0.8.2"
+
 ra_syntax = { path = "../ra_syntax" }
 ra_db = { path = "../ra_db" }
 ra_prof = { path = "../ra_prof" }

crates/ra_hir/Cargo.toml

@@ -6,13 +6,14 @@ use std::{cell::RefCell, fmt, iter::successors};
 
 use hir_def::{
     resolver::{self, HasResolver, Resolver},
-    TraitId,
+    AsMacroCall, TraitId,
 };
 use hir_expand::ExpansionInfo;
 use ra_db::{FileId, FileRange};
 use ra_prof::profile;
 use ra_syntax::{
-    algo::skip_trivia_token, ast, AstNode, Direction, SyntaxNode, SyntaxToken, TextRange, TextUnit,
+    algo::{self, skip_trivia_token},
+    ast, AstNode, Direction, SyntaxNode, SyntaxToken, TextRange, TextUnit,
 };
 use rustc_hash::{FxHashMap, FxHashSet};
 
@@ -70,6 +71,37 @@ impl<'db, DB: HirDatabase> Semantics<'db, DB> {
         Some(node)
     }
 
+    pub fn expand_hypothetical(
+        &self,
+        actual_macro_call: &ast::MacroCall,
+        hypothetical_call: &ast::MacroCall,
+        token_to_map: SyntaxToken,
+    ) -> Option<(SyntaxNode, SyntaxToken)> {
+        let macro_call =
+            self.find_file(actual_macro_call.syntax().clone()).with_value(actual_macro_call);
+        let sa = self.analyze2(macro_call.map(|it| it.syntax()), None);
+        let macro_call_id = macro_call
+            .as_call_id(self.db, |path| sa.resolver.resolve_path_as_macro(self.db, &path))?;
+        let macro_file = macro_call_id.as_file().macro_file().unwrap();
+        let (tt, tmap_1) =
+            hir_expand::syntax_node_to_token_tree(hypothetical_call.token_tree().unwrap().syntax())
+                .unwrap();
+        let range = token_to_map
+            .text_range()
+            .checked_sub(hypothetical_call.token_tree().unwrap().syntax().text_range().start())?;
+        let token_id = tmap_1.token_by_range(range)?;
+        let macro_def = hir_expand::db::expander(self.db, macro_call_id)?;
+        let (node, tmap_2) = hir_expand::db::parse_macro_with_arg(
+            self.db,
+            macro_file,
+            Some(std::sync::Arc::new((tt, tmap_1))),
+        )?;
+        let token_id = macro_def.0.map_id_down(token_id);
+        let range = tmap_2.range_by_token(token_id)?.by_kind(token_to_map.kind())?;
+        let token = algo::find_covering_element(&node.syntax_node(), range).into_token()?;
+        Some((node.syntax_node(), token))
+    }
+
     pub fn descend_into_macros(&self, token: SyntaxToken) -> SyntaxToken {
         let parent = token.parent();
         let parent = self.find_file(parent);
@@ -104,6 +136,25 @@ impl<'db, DB: HirDatabase> Semantics<'db, DB> {
         node.ancestors_with_macros(self.db).map(|it| it.value)
     }
 
+    pub fn ancestors_at_offset_with_macros(
+        &self,
+        node: &SyntaxNode,
+        offset: TextUnit,
+    ) -> impl Iterator<Item = SyntaxNode> + '_ {
+        use itertools::Itertools;
+        node.token_at_offset(offset)
+            .map(|token| self.ancestors_with_macros(token.parent()))
+            .kmerge_by(|node1, node2| node1.text_range().len() < node2.text_range().len())
+    }
+
+    pub fn find_node_at_offset_with_macros<N: AstNode>(
+        &self,
+        node: &SyntaxNode,
+        offset: TextUnit,
+    ) -> Option<N> {
+        self.ancestors_at_offset_with_macros(node, offset).find_map(N::cast)
+    }
+
     pub fn type_of_expr(&self, expr: &ast::Expr) -> Option<Type> {
         self.analyze(expr.syntax()).type_of(self.db, &expr)
     }

crates/ra_hir/src/semantics.rs

@@ -129,16 +129,43 @@ pub(crate) fn macro_arg(
 pub(crate) fn macro_expand(
     db: &dyn AstDatabase,
     id: MacroCallId,
+) -> Result<Arc<tt::Subtree>, String> {
+    macro_expand_with_arg(db, id, None)
+}
+
+// TODO hack
+pub fn expander(
+    db: &dyn AstDatabase,
+    id: MacroCallId,
+) -> Option<Arc<(TokenExpander, mbe::TokenMap)>> {
+    let lazy_id = match id {
+        MacroCallId::LazyMacro(id) => id,
+        MacroCallId::EagerMacro(_id) => {
+            // TODO
+            unimplemented!()
+        }
+    };
+
+    let loc = db.lookup_intern_macro(lazy_id);
+    let macro_rules = db.macro_def(loc.def)?;
+    Some(macro_rules)
+}
+
+pub(crate) fn macro_expand_with_arg(
+    db: &dyn AstDatabase,
+    id: MacroCallId,
+    arg: Option<Arc<(tt::Subtree, mbe::TokenMap)>>,
 ) -> Result<Arc<tt::Subtree>, String> {
     let lazy_id = match id {
         MacroCallId::LazyMacro(id) => id,
         MacroCallId::EagerMacro(id) => {
+            // TODO
             return Ok(db.lookup_intern_eager_expansion(id).subtree);
         }
     };
 
     let loc = db.lookup_intern_macro(lazy_id);
-    let macro_arg = db.macro_arg(id).ok_or("Fail to args in to tt::TokenTree")?;
+    let macro_arg = arg.or_else(|| db.macro_arg(id)).ok_or("Fail to args in to tt::TokenTree")?;
 
     let macro_rules = db.macro_def(loc.def).ok_or("Fail to find macro definition")?;
     let tt = macro_rules.0.expand(db, lazy_id, &macro_arg.0).map_err(|err| format!("{:?}", err))?;
@@ -162,12 +189,24 @@ pub(crate) fn parse_or_expand(db: &dyn AstDatabase, file_id: HirFileId) -> Optio
 pub(crate) fn parse_macro(
     db: &dyn AstDatabase,
     macro_file: MacroFile,
+) -> Option<(Parse<SyntaxNode>, Arc<mbe::TokenMap>)> {
+    parse_macro_with_arg(db, macro_file, None)
+}
+
+pub fn parse_macro_with_arg(
+    db: &dyn AstDatabase,
+    macro_file: MacroFile,
+    arg: Option<Arc<(tt::Subtree, mbe::TokenMap)>>,
 ) -> Option<(Parse<SyntaxNode>, Arc<mbe::TokenMap>)> {
     let _p = profile("parse_macro_query");
 
     let macro_call_id = macro_file.macro_call_id;
-    let tt = db
-        .macro_expand(macro_call_id)
+    let expansion = if let Some(arg) = arg {
+        macro_expand_with_arg(db, macro_call_id, Some(arg))
+    } else {
+        db.macro_expand(macro_call_id)
+    };
+    let tt = expansion
         .map_err(|err| {
             // Note:
             // The final goal we would like to make all parse_macro success,
@@ -185,15 +224,13 @@ pub(crate) fn parse_macro(
                     .collect::<Vec<_>>()
                     .join("\n");
 
-                    log::warn!(
+                    eprintln!(
                         "fail on macro_parse: (reason: {} macro_call: {:#}) parents: {}",
-                        err,
-                        node.value,
-                        parents
+                        err, node.value, parents
                     );
                 }
                 _ => {
-                    log::warn!("fail on macro_parse: (reason: {})", err);
+                    eprintln!("fail on macro_parse: (reason: {})", err);
                 }
             }
         })

crates/ra_hir_expand/src/db.rs

@@ -157,6 +157,13 @@ impl HirFileId {
             }
         }
     }
+
+    pub fn macro_file(self) -> Option<MacroFile> {
+        match self.0 {
+            HirFileIdRepr::FileId(_) => None,
+            HirFileIdRepr::MacroFile(m) => Some(m),
+        }
+    }
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
@@ -296,7 +303,7 @@ pub struct ExpansionInfo {
     exp_map: Arc<mbe::TokenMap>,
 }
 
-pub use mbe::Origin;
+pub use mbe::{syntax_node_to_token_tree, Origin};
 use ra_parser::FragmentKind;
 
 impl ExpansionInfo {

crates/ra_hir_expand/src/lib.rs

@@ -584,4 +584,102 @@ mod tests {
         "###
         );
     }
+
+    #[test]
+    fn works_in_simple_macro_1() {
+        assert_debug_snapshot!(
+            do_ref_completion(
+                r"
+                macro_rules! m { ($e:expr) => { $e } }
+                struct A { the_field: u32 }
+                fn foo(a: A) {
+                    m!(a.x<|>)
+                }
+                ",
+            ),
+            @r###"
+        [
+            CompletionItem {
+                label: "the_field",
+                source_range: [156; 157),
+                delete: [156; 157),
+                insert: "the_field",
+                kind: Field,
+                detail: "u32",
+            },
+        ]
+        "###
+        );
+    }
+
+    #[test]
+    fn works_in_simple_macro_recursive() {
+        assert_debug_snapshot!(
+            do_ref_completion(
+                r"
+                macro_rules! m { ($e:expr) => { $e } }
+                struct A { the_field: u32 }
+                fn foo(a: A) {
+                    m!(a.x<|>)
+                }
+                ",
+            ),
+            @r###"
+        [
+            CompletionItem {
+                label: "the_field",
+                source_range: [156; 157),
+                delete: [156; 157),
+                insert: "the_field",
+                kind: Field,
+                detail: "u32",
+            },
+        ]
+        "###
+        );
+    }
+
+    #[test]
+    fn works_in_simple_macro_2() {
+        // this doesn't work yet because the macro doesn't expand without the token -- maybe it can be fixed with better recovery
+        assert_debug_snapshot!(
+            do_ref_completion(
+                r"
+                macro_rules! m { ($e:expr) => { $e } }
+                struct A { the_field: u32 }
+                fn foo(a: A) {
+                    m!(a.<|>)
+                }
+                ",
+            ),
+            @r###"[]"###
+        );
+    }
+
+    #[test]
+    fn works_in_simple_macro_recursive_1() {
+        assert_debug_snapshot!(
+            do_ref_completion(
+                r"
+                macro_rules! m { ($e:expr) => { $e } }
+                struct A { the_field: u32 }
+                fn foo(a: A) {
+                    m!(m!(m!(a.x<|>)))
+                }
+                ",
+            ),
+            @r###"
+        [
+            CompletionItem {
+                label: "the_field",
+                source_range: [162; 163),
+                delete: [162; 163),
+                insert: "the_field",
+                kind: Field,
+                detail: "u32",
+            },
+        ]
+        "###
+        );
+    }
 }

crates/ra_ide/src/completion/complete_dot.rs

@@ -1,4 +1,4 @@
-//! Completion of paths, including when writing a single name.
+//! Completion of paths, i.e. `some::prefix::<|>`.
 
 use hir::{Adt, PathResolution, ScopeDef};
 use ra_syntax::AstNode;

crates/ra_ide/src/completion/complete_path.rs

@@ -1,4 +1,4 @@
-//! FIXME: write short doc here
+//! Completion of names from the current scope, e.g. locals and imported items.
 
 use crate::completion::{CompletionContext, Completions};
 
@@ -797,4 +797,72 @@ mod tests {
         "###
         )
     }
+
+    #[test]
+    fn completes_in_simple_macro_1() {
+        assert_debug_snapshot!(
+            do_reference_completion(
+                r"
+                macro_rules! m { ($e:expr) => { $e } }
+                fn quux(x: i32) {
+                    let y = 92;
+                    m!(<|>);
+                }
+                "
+            ),
+            @"[]"
+        );
+    }
+
+    #[test]
+    fn completes_in_simple_macro_2() {
+        assert_debug_snapshot!(
+            do_reference_completion(
+                r"
+                macro_rules! m { ($e:expr) => { $e } }
+                fn quux(x: i32) {
+                    let y = 92;
+                    m!(x<|>);
+                }
+                "
+            ),
+            @r###"
+        [
+            CompletionItem {
+                label: "m!",
+                source_range: [145; 146),
+                delete: [145; 146),
+                insert: "m!($0)",
+                kind: Macro,
+                detail: "macro_rules! m",
+            },
+            CompletionItem {
+                label: "quux(…)",
+                source_range: [145; 146),
+                delete: [145; 146),
+                insert: "quux(${1:x})$0",
+                kind: Function,
+                lookup: "quux",
+                detail: "fn quux(x: i32)",
+            },
+            CompletionItem {
+                label: "x",
+                source_range: [145; 146),
+                delete: [145; 146),
+                insert: "x",
+                kind: Binding,
+                detail: "i32",
+            },
+            CompletionItem {
+                label: "y",
+                source_range: [145; 146),
+                delete: [145; 146),
+                insert: "y",
+                kind: Binding,
+                detail: "i32",
+            },
+        ]
+        "###
+        );
+    }
 }