From 4f8a49f43cad086a656626c43062ff89b46f505a Mon Sep 17 00:00:00 2001 From: Florian Diebold Date: Sun, 14 Apr 2019 16:08:10 +0200 Subject: Refactor method candidate generation a bit This fixes the order in which candidates are chosen a bit (not completely though, as the ignored test demonstrates), and makes autoderef work with trait methods. As a side effect, this also makes completion of trait methods work :) --- crates/ra_hir/src/source_binder.rs | 12 ++- crates/ra_hir/src/ty/method_resolution.rs | 126 +++++++++++++++++------------- crates/ra_hir/src/ty/tests.rs | 65 +++++++++++++++ 3 files changed, 149 insertions(+), 54 deletions(-) (limited to 'crates/ra_hir') diff --git a/crates/ra_hir/src/source_binder.rs b/crates/ra_hir/src/source_binder.rs index bd035ced9..f1bb13bc6 100644 --- a/crates/ra_hir/src/source_binder.rs +++ b/crates/ra_hir/src/source_binder.rs @@ -18,7 +18,7 @@ use ra_syntax::{ use crate::{ HirDatabase, Function, Struct, Enum, Const, Static, Either, DefWithBody, PerNs, Name, - AsName, Module, HirFileId, Crate, Trait, Resolver, + AsName, Module, HirFileId, Crate, Trait, Resolver, Ty, expr::{BodySourceMap, scope::{ScopeId, ExprScopes}}, ids::LocationCtx, expr, AstId @@ -343,6 +343,16 @@ impl SourceAnalyzer { .collect() } + pub fn iterate_method_candidates( + &self, + db: &impl HirDatabase, + ty: Ty, + name: Option<&Name>, + callback: impl FnMut(&Ty, Function) -> Option, + ) -> Option { + ty.iterate_method_candidates(db, &self.resolver, name, callback) + } + #[cfg(test)] pub(crate) fn body_source_map(&self) -> Arc { self.body_source_map.clone().unwrap() diff --git a/crates/ra_hir/src/ty/method_resolution.rs b/crates/ra_hir/src/ty/method_resolution.rs index 6b7918187..667b66095 100644 --- a/crates/ra_hir/src/ty/method_resolution.rs +++ b/crates/ra_hir/src/ty/method_resolution.rs @@ -129,85 +129,105 @@ impl Ty { name: &Name, resolver: &Resolver, ) -> Option<(Ty, Function)> { - // FIXME: trait methods should be used before autoderefs - // (and we need to do autoderefs for trait method calls as well) - let inherent_method = self.clone().iterate_methods(db, |ty, f| { - let sig = f.signature(db); - if sig.name() == name && sig.has_self_param() { - Some((ty.clone(), f)) - } else { - None - } - }); - inherent_method.or_else(|| self.lookup_trait_method(db, name, resolver)) + self.iterate_method_candidates(db, resolver, Some(name), |ty, f| Some((ty.clone(), f))) } - fn lookup_trait_method( + // This would be nicer if it just returned an iterator, but that runs into + // lifetime problems, because we need to borrow temp `CrateImplBlocks`. + pub(crate) fn iterate_method_candidates( self, db: &impl HirDatabase, - name: &Name, resolver: &Resolver, - ) -> Option<(Ty, Function)> { - let mut candidates = Vec::new(); - for t in resolver.traits_in_scope() { + name: Option<&Name>, + mut callback: impl FnMut(&Ty, Function) -> Option, + ) -> Option { + // For method calls, rust first does any number of autoderef, and then one + // autoref (i.e. when the method takes &self or &mut self). We just ignore + // the autoref currently -- when we find a method matching the given name, + // we assume it fits. + + // Also note that when we've got a receiver like &S, even if the method we + // find in the end takes &self, we still do the autoderef step (just as + // rustc does an autoderef and then autoref again). + + for derefed_ty in self.autoderef(db) { + if let Some(result) = derefed_ty.iterate_inherent_methods(db, name, &mut callback) { + return Some(result); + } + if let Some(result) = + derefed_ty.iterate_trait_method_candidates(db, resolver, name, &mut callback) + { + return Some(result); + } + } + None + } + + fn iterate_trait_method_candidates( + &self, + db: &impl HirDatabase, + resolver: &Resolver, + name: Option<&Name>, + mut callback: impl FnMut(&Ty, Function) -> Option, + ) -> Option { + 'traits: for t in resolver.traits_in_scope() { let data = t.trait_data(db); + // we'll be lazy about checking whether the type implements the + // trait, but if we find out it doesn't, we'll skip the rest of the + // iteration + let mut known_implemented = false; for item in data.items() { match item { &TraitItem::Function(m) => { let sig = m.signature(db); - if sig.name() == name && sig.has_self_param() { - candidates.push((t, m)); + if name.map_or(true, |name| sig.name() == name) && sig.has_self_param() { + if !known_implemented { + let trait_ref = TraitRef { + trait_: t, + substs: fresh_substs_for_trait(db, t, self.clone()), + }; + let (trait_ref, _) = super::traits::canonicalize(trait_ref); + if db.implements(trait_ref).is_none() { + continue 'traits; + } + } + known_implemented = true; + if let Some(result) = callback(self, m) { + return Some(result); + } } } _ => {} } } } - candidates.retain(|(t, _m)| { - let trait_ref = - TraitRef { trait_: *t, substs: fresh_substs_for_trait(db, *t, self.clone()) }; - let (trait_ref, _) = super::traits::canonicalize(trait_ref); - db.implements(trait_ref).is_some() - }); - // FIXME if there's multiple candidates here, that's an ambiguity error - let (_chosen_trait, chosen_method) = candidates.first()?; - // FIXME return correct receiver type - Some((self.clone(), *chosen_method)) + None } - // This would be nicer if it just returned an iterator, but that runs into - // lifetime problems, because we need to borrow temp `CrateImplBlocks`. - pub fn iterate_methods( - self, + fn iterate_inherent_methods( + &self, db: &impl HirDatabase, + name: Option<&Name>, mut callback: impl FnMut(&Ty, Function) -> Option, ) -> Option { - // For method calls, rust first does any number of autoderef, and then one - // autoref (i.e. when the method takes &self or &mut self). We just ignore - // the autoref currently -- when we find a method matching the given name, - // we assume it fits. - - // Also note that when we've got a receiver like &S, even if the method we - // find in the end takes &self, we still do the autoderef step (just as - // rustc does an autoderef and then autoref again). + let krate = match def_crate(db, self) { + Some(krate) => krate, + None => return None, + }; + let impls = db.impls_in_crate(krate); - for derefed_ty in self.autoderef(db) { - let krate = match def_crate(db, &derefed_ty) { - Some(krate) => krate, - None => continue, - }; - let impls = db.impls_in_crate(krate); - - for impl_block in impls.lookup_impl_blocks(&derefed_ty) { - for item in impl_block.items(db) { - match item { - ImplItem::Method(f) => { - if let Some(result) = callback(&derefed_ty, f) { + for impl_block in impls.lookup_impl_blocks(self) { + for item in impl_block.items(db) { + match item { + ImplItem::Method(f) => { + let sig = f.signature(db); + if name.map_or(true, |name| sig.name() == name) && sig.has_self_param() { + if let Some(result) = callback(self, f) { return Some(result); } } - _ => {} } + _ => {} } } } diff --git a/crates/ra_hir/src/ty/tests.rs b/crates/ra_hir/src/ty/tests.rs index 291bc9ae5..82c4aeddb 100644 --- a/crates/ra_hir/src/ty/tests.rs +++ b/crates/ra_hir/src/ty/tests.rs @@ -2336,6 +2336,66 @@ fn test() -> u64 { ); } +#[ignore] +#[test] +fn method_resolution_trait_before_autoref() { + let t = type_at( + r#" +//- /main.rs +trait Trait { fn foo(self) -> u128; } +struct S; +impl S { fn foo(&self) -> i8 { 0 } } +impl Trait for S { fn foo(self) -> u128 { 0 } } +fn test() { S.foo()<|>; } +"#, + ); + assert_eq!(t, "u128"); +} + +#[test] +fn method_resolution_trait_before_autoderef() { + let t = type_at( + r#" +//- /main.rs +trait Trait { fn foo(self) -> u128; } +struct S; +impl S { fn foo(self) -> i8 { 0 } } +impl Trait for &S { fn foo(self) -> u128 { 0 } } +fn test() { (&S).foo()<|>; } +"#, + ); + assert_eq!(t, "u128"); +} + +#[test] +fn method_resolution_impl_before_trait() { + let t = type_at( + r#" +//- /main.rs +trait Trait { fn foo(self) -> u128; } +struct S; +impl S { fn foo(self) -> i8 { 0 } } +impl Trait for S { fn foo(self) -> u128 { 0 } } +fn test() { S.foo()<|>; } +"#, + ); + assert_eq!(t, "i8"); +} + +#[test] +fn method_resolution_trait_autoderef() { + let t = type_at( + r#" +//- /main.rs +trait Trait { fn foo(self) -> u128; } +struct S; +impl Trait for S { fn foo(self) -> u128 { 0 } } +fn test() { (&S).foo()<|>; } +"#, + ); + assert_eq!(t, "u128"); +} + fn type_at_pos(db: &MockDatabase, pos: FilePosition) -> String { let file = db.parse(pos.file_id); let expr = algo::find_node_at_offset::(file.syntax(), pos.offset).unwrap(); @@ -2344,6 +2404,11 @@ fn type_at_pos(db: &MockDatabase, pos: FilePosition) -> String { ty.display(db).to_string() } +fn type_at(content: &str) -> String { + let (db, file_pos) = MockDatabase::with_position(content); + type_at_pos(&db, file_pos) +} + fn infer(content: &str) -> String { let (db, _, file_id) = MockDatabase::with_single_file(content); let source_file = db.parse(file_id); -- cgit v1.2.3