From 47d7434dde215460fc95916f2703c6925f58dcce Mon Sep 17 00:00:00 2001 From: Aleksey Kladov Date: Tue, 18 May 2021 14:42:41 +0300 Subject: internal: replace AstTransformer with mutable syntax trees --- crates/ide_assists/src/ast_transform.rs | 236 ++++++++++++-------------------- crates/ide_assists/src/utils.rs | 22 +-- crates/syntax/src/ast/edit.rs | 56 +------- crates/syntax/src/ast/edit_in_place.rs | 10 ++ crates/syntax/src/ast/make.rs | 4 + crates/syntax/src/ted.rs | 3 + 6 files changed, 123 insertions(+), 208 deletions(-) (limited to 'crates') diff --git a/crates/ide_assists/src/ast_transform.rs b/crates/ide_assists/src/ast_transform.rs index e5ae718c9..5d9cc5551 100644 --- a/crates/ide_assists/src/ast_transform.rs +++ b/crates/ide_assists/src/ast_transform.rs @@ -1,31 +1,12 @@ //! `AstTransformer`s are functions that replace nodes in an AST and can be easily combined. -use hir::{HirDisplay, PathResolution, SemanticsScope}; +use hir::{HirDisplay, SemanticsScope}; use ide_db::helpers::mod_path_to_ast; use rustc_hash::FxHashMap; use syntax::{ ast::{self, AstNode}, - ted, SyntaxNode, + ted, }; -pub fn apply<'a, N: AstNode>(transformer: &dyn AstTransform<'a>, node: &N) { - let mut skip_to = None; - for event in node.syntax().preorder() { - match event { - syntax::WalkEvent::Enter(node) if skip_to.is_none() => { - skip_to = transformer.get_substitution(&node, transformer).zip(Some(node)); - } - syntax::WalkEvent::Enter(_) => (), - syntax::WalkEvent::Leave(node) => match &skip_to { - Some((replacement, skip_target)) if *skip_target == node => { - ted::replace(node, replacement.clone_for_update()); - skip_to.take(); - } - _ => (), - }, - } - } -} - /// `AstTransform` helps with applying bulk transformations to syntax nodes. /// /// This is mostly useful for IDE code generation. If you paste some existing @@ -35,8 +16,8 @@ pub fn apply<'a, N: AstNode>(transformer: &dyn AstTransform<'a>, node: &N) { /// /// ``` /// mod x { -/// pub struct A; -/// pub trait T { fn foo(&self, _: U) -> A; } +/// pub struct A; +/// pub trait T { fn foo(&self, _: U) -> A; } /// } /// /// mod y { @@ -45,7 +26,7 @@ pub fn apply<'a, N: AstNode>(transformer: &dyn AstTransform<'a>, node: &N) { /// impl T<()> for () { /// // If we invoke **Add Missing Members** here, we want to copy-paste `foo`. /// // But we want a slightly-modified version of it: -/// fn foo(&self, _: ()) -> x::A {} +/// fn foo(&self, _: ()) -> x::A<()> {} /// } /// } /// ``` @@ -54,49 +35,27 @@ pub fn apply<'a, N: AstNode>(transformer: &dyn AstTransform<'a>, node: &N) { /// `SyntaxNode`. Note that the API here is a bit too high-order and high-brow. /// We'd want to somehow express this concept simpler, but so far nobody got to /// simplifying this! -pub trait AstTransform<'a> { - fn get_substitution( - &self, - node: &SyntaxNode, - recur: &dyn AstTransform<'a>, - ) -> Option; - - fn or + 'a>(self, other: T) -> Box + 'a> - where - Self: Sized + 'a, - { - Box::new(Or(Box::new(self), Box::new(other))) - } +pub(crate) struct AstTransform<'a> { + pub(crate) subst: (hir::Trait, ast::Impl), + pub(crate) target_scope: &'a SemanticsScope<'a>, + pub(crate) source_scope: &'a SemanticsScope<'a>, } -struct Or<'a>(Box + 'a>, Box + 'a>); - -impl<'a> AstTransform<'a> for Or<'a> { - fn get_substitution( - &self, - node: &SyntaxNode, - recur: &dyn AstTransform<'a>, - ) -> Option { - self.0.get_substitution(node, recur).or_else(|| self.1.get_substitution(node, recur)) +impl<'a> AstTransform<'a> { + pub(crate) fn apply(&self, item: ast::AssocItem) { + if let Some(ctx) = self.build_ctx() { + ctx.apply(item) + } } -} - -pub struct SubstituteTypeParams<'a> { - source_scope: &'a SemanticsScope<'a>, - substs: FxHashMap, -} + fn build_ctx(&self) -> Option> { + let db = self.source_scope.db; + let target_module = self.target_scope.module()?; + let source_module = self.source_scope.module()?; -impl<'a> SubstituteTypeParams<'a> { - pub fn for_trait_impl( - source_scope: &'a SemanticsScope<'a>, - // FIXME: there's implicit invariant that `trait_` and `source_scope` match... - trait_: hir::Trait, - impl_def: ast::Impl, - ) -> SubstituteTypeParams<'a> { - let substs = get_syntactic_substs(impl_def).unwrap_or_default(); - let generic_def: hir::GenericDef = trait_.into(); + let substs = get_syntactic_substs(self.subst.1.clone()).unwrap_or_default(); + let generic_def: hir::GenericDef = self.subst.0.into(); let substs_by_param: FxHashMap<_, _> = generic_def - .type_params(source_scope.db) + .type_params(db) .into_iter() // this is a trait impl, so we need to skip the first type parameter -- this is a bit hacky .skip(1) @@ -110,109 +69,96 @@ impl<'a> SubstituteTypeParams<'a> { .filter_map(|(k, v)| match v { Some(v) => Some((k, v)), None => { - let default = k.default(source_scope.db)?; + let default = k.default(db)?; Some(( k, - ast::make::ty( - &default - .display_source_code(source_scope.db, source_scope.module()?.into()) - .ok()?, - ), + ast::make::ty(&default.display_source_code(db, source_module.into()).ok()?), )) } }) .collect(); - return SubstituteTypeParams { source_scope, substs: substs_by_param }; - - // FIXME: It would probably be nicer if we could get this via HIR (i.e. get the - // trait ref, and then go from the types in the substs back to the syntax). - fn get_syntactic_substs(impl_def: ast::Impl) -> Option> { - let target_trait = impl_def.trait_()?; - let path_type = match target_trait { - ast::Type::PathType(path) => path, - _ => return None, - }; - let generic_arg_list = path_type.path()?.segment()?.generic_arg_list()?; - - let mut result = Vec::new(); - for generic_arg in generic_arg_list.generic_args() { - match generic_arg { - ast::GenericArg::TypeArg(type_arg) => result.push(type_arg.ty()?), - ast::GenericArg::AssocTypeArg(_) - | ast::GenericArg::LifetimeArg(_) - | ast::GenericArg::ConstArg(_) => (), - } - } - Some(result) - } + let res = Ctx { substs: substs_by_param, target_module, source_scope: self.source_scope }; + Some(res) } } -impl<'a> AstTransform<'a> for SubstituteTypeParams<'a> { - fn get_substitution( - &self, - node: &SyntaxNode, - _recur: &dyn AstTransform<'a>, - ) -> Option { - let type_ref = ast::Type::cast(node.clone())?; - let path = match &type_ref { - ast::Type::PathType(path_type) => path_type.path()?, - _ => return None, - }; - let resolution = self.source_scope.speculative_resolve(&path)?; - match resolution { - hir::PathResolution::TypeParam(tp) => Some(self.substs.get(&tp)?.syntax().clone()), - _ => None, - } - } -} - -pub struct QualifyPaths<'a> { - target_scope: &'a SemanticsScope<'a>, +struct Ctx<'a> { + substs: FxHashMap, + target_module: hir::Module, source_scope: &'a SemanticsScope<'a>, } -impl<'a> QualifyPaths<'a> { - pub fn new(target_scope: &'a SemanticsScope<'a>, source_scope: &'a SemanticsScope<'a>) -> Self { - Self { target_scope, source_scope } +impl<'a> Ctx<'a> { + fn apply(&self, item: ast::AssocItem) { + for event in item.syntax().preorder() { + let node = match event { + syntax::WalkEvent::Enter(_) => continue, + syntax::WalkEvent::Leave(it) => it, + }; + if let Some(path) = ast::Path::cast(node.clone()) { + self.transform_path(path); + } + } } -} - -impl<'a> AstTransform<'a> for QualifyPaths<'a> { - fn get_substitution( - &self, - node: &SyntaxNode, - recur: &dyn AstTransform<'a>, - ) -> Option { - // FIXME handle value ns? - let from = self.target_scope.module()?; - let p = ast::Path::cast(node.clone())?; - if p.segment().and_then(|s| s.param_list()).is_some() { + fn transform_path(&self, path: ast::Path) -> Option<()> { + if path.qualifier().is_some() { + return None; + } + if path.segment().and_then(|s| s.param_list()).is_some() { // don't try to qualify `Fn(Foo) -> Bar` paths, they are in prelude anyway return None; } - let resolution = self.source_scope.speculative_resolve(&p)?; - match resolution { - PathResolution::Def(def) => { - let found_path = from.find_use_path(self.source_scope.db.upcast(), def)?; - let mut path = mod_path_to_ast(&found_path); - let type_args = p.segment().and_then(|s| s.generic_arg_list()); - if let Some(type_args) = type_args { - apply(recur, &type_args); - let last_segment = path.segment().unwrap(); - path = path.with_segment(last_segment.with_generic_args(type_args)) - } + let resolution = self.source_scope.speculative_resolve(&path)?; - Some(path.syntax().clone()) + match resolution { + hir::PathResolution::TypeParam(tp) => { + if let Some(subst) = self.substs.get(&tp) { + ted::replace(path.syntax(), subst.clone_subtree().clone_for_update().syntax()) + } + } + hir::PathResolution::Def(def) => { + let found_path = + self.target_module.find_use_path(self.source_scope.db.upcast(), def)?; + let res = mod_path_to_ast(&found_path).clone_for_update(); + if let Some(args) = path.segment().and_then(|it| it.generic_arg_list()) { + if let Some(segment) = res.segment() { + let old = segment.get_or_create_generic_arg_list(); + ted::replace(old.syntax(), args.clone_subtree().syntax().clone_for_update()) + } + } + ted::replace(path.syntax(), res.syntax()) } - PathResolution::Local(_) - | PathResolution::TypeParam(_) - | PathResolution::SelfType(_) - | PathResolution::ConstParam(_) => None, - PathResolution::Macro(_) => None, - PathResolution::AssocItem(_) => None, + hir::PathResolution::Local(_) + | hir::PathResolution::ConstParam(_) + | hir::PathResolution::SelfType(_) + | hir::PathResolution::Macro(_) + | hir::PathResolution::AssocItem(_) => (), } + Some(()) } } + +// FIXME: It would probably be nicer if we could get this via HIR (i.e. get the +// trait ref, and then go from the types in the substs back to the syntax). +fn get_syntactic_substs(impl_def: ast::Impl) -> Option> { + let target_trait = impl_def.trait_()?; + let path_type = match target_trait { + ast::Type::PathType(path) => path, + _ => return None, + }; + let generic_arg_list = path_type.path()?.segment()?.generic_arg_list()?; + + let mut result = Vec::new(); + for generic_arg in generic_arg_list.generic_args() { + match generic_arg { + ast::GenericArg::TypeArg(type_arg) => result.push(type_arg.ty()?), + ast::GenericArg::AssocTypeArg(_) + | ast::GenericArg::LifetimeArg(_) + | ast::GenericArg::ConstArg(_) => (), + } + } + + Some(result) +} diff --git a/crates/ide_assists/src/utils.rs b/crates/ide_assists/src/utils.rs index fc7caee04..2e79a3aed 100644 --- a/crates/ide_assists/src/utils.rs +++ b/crates/ide_assists/src/utils.rs @@ -24,7 +24,7 @@ use syntax::{ use crate::{ assist_context::{AssistBuilder, AssistContext}, - ast_transform::{self, AstTransform, QualifyPaths, SubstituteTypeParams}, + ast_transform::AstTransform, }; pub(crate) fn unwrap_trivial_block(block: ast::BlockExpr) -> ast::Expr { @@ -132,14 +132,18 @@ pub fn add_trait_assoc_items_to_impl( target_scope: hir::SemanticsScope, ) -> (ast::Impl, ast::AssocItem) { let source_scope = sema.scope_for_def(trait_); - let ast_transform = QualifyPaths::new(&target_scope, &source_scope) - .or(SubstituteTypeParams::for_trait_impl(&source_scope, trait_, impl_.clone())); - - let items = items - .into_iter() - .map(|it| it.clone_for_update()) - .inspect(|it| ast_transform::apply(&*ast_transform, it)) - .map(|it| edit::remove_attrs_and_docs(&it).clone_subtree().clone_for_update()); + + let transform = AstTransform { + subst: (trait_, impl_.clone()), + source_scope: &source_scope, + target_scope: &target_scope, + }; + + let items = items.into_iter().map(|assoc_item| { + let assoc_item = assoc_item.clone_for_update(); + transform.apply(assoc_item.clone()); + edit::remove_attrs_and_docs(&assoc_item).clone_subtree().clone_for_update() + }); let res = impl_.clone_for_update(); diff --git a/crates/syntax/src/ast/edit.rs b/crates/syntax/src/ast/edit.rs index 61952377f..19107ee38 100644 --- a/crates/syntax/src/ast/edit.rs +++ b/crates/syntax/src/ast/edit.rs @@ -6,14 +6,12 @@ use std::{ ops::{self, RangeInclusive}, }; -use arrayvec::ArrayVec; - use crate::{ algo, ast::{self, make, AstNode}, - ted, AstToken, InsertPosition, NodeOrToken, SyntaxElement, SyntaxKind, + ted, AstToken, NodeOrToken, SyntaxElement, SyntaxKind, SyntaxKind::{ATTR, COMMENT, WHITESPACE}, - SyntaxNode, SyntaxToken, T, + SyntaxNode, SyntaxToken, }; impl ast::BinExpr { @@ -25,46 +23,6 @@ impl ast::BinExpr { } } -impl ast::Path { - #[must_use] - pub fn with_segment(&self, segment: ast::PathSegment) -> ast::Path { - if let Some(old) = self.segment() { - return self.replace_children( - single_node(old.syntax().clone()), - iter::once(segment.syntax().clone().into()), - ); - } - self.clone() - } -} - -impl ast::PathSegment { - #[must_use] - pub fn with_generic_args(&self, type_args: ast::GenericArgList) -> ast::PathSegment { - self._with_generic_args(type_args, false) - } - - #[must_use] - pub fn with_turbo_fish(&self, type_args: ast::GenericArgList) -> ast::PathSegment { - self._with_generic_args(type_args, true) - } - - fn _with_generic_args(&self, type_args: ast::GenericArgList, turbo: bool) -> ast::PathSegment { - if let Some(old) = self.generic_arg_list() { - return self.replace_children( - single_node(old.syntax().clone()), - iter::once(type_args.syntax().clone().into()), - ); - } - let mut to_insert: ArrayVec = ArrayVec::new(); - if turbo { - to_insert.push(make::token(T![::]).into()); - } - to_insert.push(type_args.syntax().clone().into()); - self.insert_children(InsertPosition::Last, to_insert) - } -} - impl ast::UseTree { /// Splits off the given prefix, making it the path component of the use tree, appending the rest of the path to all UseTreeList items. #[must_use] @@ -233,16 +191,6 @@ fn prev_tokens(token: SyntaxToken) -> impl Iterator { } pub trait AstNodeEdit: AstNode + Clone + Sized { - #[must_use] - fn insert_children( - &self, - position: InsertPosition, - to_insert: impl IntoIterator, - ) -> Self { - let new_syntax = algo::insert_children(self.syntax(), position, to_insert); - Self::cast(new_syntax).unwrap() - } - #[must_use] fn replace_children( &self, diff --git a/crates/syntax/src/ast/edit_in_place.rs b/crates/syntax/src/ast/edit_in_place.rs index 2676ed8c9..ca8103668 100644 --- a/crates/syntax/src/ast/edit_in_place.rs +++ b/crates/syntax/src/ast/edit_in_place.rs @@ -239,6 +239,16 @@ impl ast::TypeBoundList { } } +impl ast::PathSegment { + pub fn get_or_create_generic_arg_list(&self) -> ast::GenericArgList { + if self.generic_arg_list().is_none() { + let arg_list = make::generic_arg_list().clone_for_update(); + ted::append_child(self.syntax(), arg_list.syntax()) + } + self.generic_arg_list().unwrap() + } +} + impl ast::UseTree { pub fn remove(&self) { for &dir in [Direction::Next, Direction::Prev].iter() { diff --git a/crates/syntax/src/ast/make.rs b/crates/syntax/src/ast/make.rs index d13926ded..0cf170626 100644 --- a/crates/syntax/src/ast/make.rs +++ b/crates/syntax/src/ast/make.rs @@ -106,6 +106,10 @@ pub fn impl_trait(trait_: ast::Path, ty: ast::Path) -> ast::Impl { ast_from_text(&format!("impl {} for {} {{}}", trait_, ty)) } +pub(crate) fn generic_arg_list() -> ast::GenericArgList { + ast_from_text("const S: T<> = ();") +} + pub fn path_segment(name_ref: ast::NameRef) -> ast::PathSegment { ast_from_text(&format!("use {};", name_ref)) } diff --git a/crates/syntax/src/ted.rs b/crates/syntax/src/ted.rs index a50c0dbca..ae970f44f 100644 --- a/crates/syntax/src/ted.rs +++ b/crates/syntax/src/ted.rs @@ -184,6 +184,9 @@ fn ws_between(left: &SyntaxElement, right: &SyntaxElement) -> Option Date: Sat, 22 May 2021 16:23:07 +0300 Subject: use more precise name --- crates/ide_assists/src/ast_transform.rs | 164 ------------------------------- crates/ide_assists/src/lib.rs | 2 +- crates/ide_assists/src/path_transform.rs | 159 ++++++++++++++++++++++++++++++ crates/ide_assists/src/utils.rs | 4 +- 4 files changed, 162 insertions(+), 167 deletions(-) delete mode 100644 crates/ide_assists/src/ast_transform.rs create mode 100644 crates/ide_assists/src/path_transform.rs (limited to 'crates') diff --git a/crates/ide_assists/src/ast_transform.rs b/crates/ide_assists/src/ast_transform.rs deleted file mode 100644 index 5d9cc5551..000000000 --- a/crates/ide_assists/src/ast_transform.rs +++ /dev/null @@ -1,164 +0,0 @@ -//! `AstTransformer`s are functions that replace nodes in an AST and can be easily combined. -use hir::{HirDisplay, SemanticsScope}; -use ide_db::helpers::mod_path_to_ast; -use rustc_hash::FxHashMap; -use syntax::{ - ast::{self, AstNode}, - ted, -}; - -/// `AstTransform` helps with applying bulk transformations to syntax nodes. -/// -/// This is mostly useful for IDE code generation. If you paste some existing -/// code into a new context (for example, to add method overrides to an `impl` -/// block), you generally want to appropriately qualify the names, and sometimes -/// you might want to substitute generic parameters as well: -/// -/// ``` -/// mod x { -/// pub struct A; -/// pub trait T { fn foo(&self, _: U) -> A; } -/// } -/// -/// mod y { -/// use x::T; -/// -/// impl T<()> for () { -/// // If we invoke **Add Missing Members** here, we want to copy-paste `foo`. -/// // But we want a slightly-modified version of it: -/// fn foo(&self, _: ()) -> x::A<()> {} -/// } -/// } -/// ``` -/// -/// So, a single `AstTransform` describes such function from `SyntaxNode` to -/// `SyntaxNode`. Note that the API here is a bit too high-order and high-brow. -/// We'd want to somehow express this concept simpler, but so far nobody got to -/// simplifying this! -pub(crate) struct AstTransform<'a> { - pub(crate) subst: (hir::Trait, ast::Impl), - pub(crate) target_scope: &'a SemanticsScope<'a>, - pub(crate) source_scope: &'a SemanticsScope<'a>, -} - -impl<'a> AstTransform<'a> { - pub(crate) fn apply(&self, item: ast::AssocItem) { - if let Some(ctx) = self.build_ctx() { - ctx.apply(item) - } - } - fn build_ctx(&self) -> Option> { - let db = self.source_scope.db; - let target_module = self.target_scope.module()?; - let source_module = self.source_scope.module()?; - - let substs = get_syntactic_substs(self.subst.1.clone()).unwrap_or_default(); - let generic_def: hir::GenericDef = self.subst.0.into(); - let substs_by_param: FxHashMap<_, _> = generic_def - .type_params(db) - .into_iter() - // this is a trait impl, so we need to skip the first type parameter -- this is a bit hacky - .skip(1) - // The actual list of trait type parameters may be longer than the one - // used in the `impl` block due to trailing default type parameters. - // For that case we extend the `substs` with an empty iterator so we - // can still hit those trailing values and check if they actually have - // a default type. If they do, go for that type from `hir` to `ast` so - // the resulting change can be applied correctly. - .zip(substs.into_iter().map(Some).chain(std::iter::repeat(None))) - .filter_map(|(k, v)| match v { - Some(v) => Some((k, v)), - None => { - let default = k.default(db)?; - Some(( - k, - ast::make::ty(&default.display_source_code(db, source_module.into()).ok()?), - )) - } - }) - .collect(); - - let res = Ctx { substs: substs_by_param, target_module, source_scope: self.source_scope }; - Some(res) - } -} - -struct Ctx<'a> { - substs: FxHashMap, - target_module: hir::Module, - source_scope: &'a SemanticsScope<'a>, -} - -impl<'a> Ctx<'a> { - fn apply(&self, item: ast::AssocItem) { - for event in item.syntax().preorder() { - let node = match event { - syntax::WalkEvent::Enter(_) => continue, - syntax::WalkEvent::Leave(it) => it, - }; - if let Some(path) = ast::Path::cast(node.clone()) { - self.transform_path(path); - } - } - } - fn transform_path(&self, path: ast::Path) -> Option<()> { - if path.qualifier().is_some() { - return None; - } - if path.segment().and_then(|s| s.param_list()).is_some() { - // don't try to qualify `Fn(Foo) -> Bar` paths, they are in prelude anyway - return None; - } - - let resolution = self.source_scope.speculative_resolve(&path)?; - - match resolution { - hir::PathResolution::TypeParam(tp) => { - if let Some(subst) = self.substs.get(&tp) { - ted::replace(path.syntax(), subst.clone_subtree().clone_for_update().syntax()) - } - } - hir::PathResolution::Def(def) => { - let found_path = - self.target_module.find_use_path(self.source_scope.db.upcast(), def)?; - let res = mod_path_to_ast(&found_path).clone_for_update(); - if let Some(args) = path.segment().and_then(|it| it.generic_arg_list()) { - if let Some(segment) = res.segment() { - let old = segment.get_or_create_generic_arg_list(); - ted::replace(old.syntax(), args.clone_subtree().syntax().clone_for_update()) - } - } - ted::replace(path.syntax(), res.syntax()) - } - hir::PathResolution::Local(_) - | hir::PathResolution::ConstParam(_) - | hir::PathResolution::SelfType(_) - | hir::PathResolution::Macro(_) - | hir::PathResolution::AssocItem(_) => (), - } - Some(()) - } -} - -// FIXME: It would probably be nicer if we could get this via HIR (i.e. get the -// trait ref, and then go from the types in the substs back to the syntax). -fn get_syntactic_substs(impl_def: ast::Impl) -> Option> { - let target_trait = impl_def.trait_()?; - let path_type = match target_trait { - ast::Type::PathType(path) => path, - _ => return None, - }; - let generic_arg_list = path_type.path()?.segment()?.generic_arg_list()?; - - let mut result = Vec::new(); - for generic_arg in generic_arg_list.generic_args() { - match generic_arg { - ast::GenericArg::TypeArg(type_arg) => result.push(type_arg.ty()?), - ast::GenericArg::AssocTypeArg(_) - | ast::GenericArg::LifetimeArg(_) - | ast::GenericArg::ConstArg(_) => (), - } - } - - Some(result) -} diff --git a/crates/ide_assists/src/lib.rs b/crates/ide_assists/src/lib.rs index 2e0c58504..05644b6ff 100644 --- a/crates/ide_assists/src/lib.rs +++ b/crates/ide_assists/src/lib.rs @@ -15,7 +15,7 @@ mod assist_context; #[cfg(test)] mod tests; pub mod utils; -pub mod ast_transform; +pub mod path_transform; use std::str::FromStr; diff --git a/crates/ide_assists/src/path_transform.rs b/crates/ide_assists/src/path_transform.rs new file mode 100644 index 000000000..6ec318c4c --- /dev/null +++ b/crates/ide_assists/src/path_transform.rs @@ -0,0 +1,159 @@ +//! See `PathTransform` +use hir::{HirDisplay, SemanticsScope}; +use ide_db::helpers::mod_path_to_ast; +use rustc_hash::FxHashMap; +use syntax::{ + ast::{self, AstNode}, + ted, +}; + +/// `PathTransform` substitutes path in SyntaxNodes in bulk. +/// +/// This is mostly useful for IDE code generation. If you paste some existing +/// code into a new context (for example, to add method overrides to an `impl` +/// block), you generally want to appropriately qualify the names, and sometimes +/// you might want to substitute generic parameters as well: +/// +/// ``` +/// mod x { +/// pub struct A; +/// pub trait T { fn foo(&self, _: U) -> A; } +/// } +/// +/// mod y { +/// use x::T; +/// +/// impl T<()> for () { +/// // If we invoke **Add Missing Members** here, we want to copy-paste `foo`. +/// // But we want a slightly-modified version of it: +/// fn foo(&self, _: ()) -> x::A<()> {} +/// } +/// } +/// ``` +pub(crate) struct PathTransform<'a> { + pub(crate) subst: (hir::Trait, ast::Impl), + pub(crate) target_scope: &'a SemanticsScope<'a>, + pub(crate) source_scope: &'a SemanticsScope<'a>, +} + +impl<'a> PathTransform<'a> { + pub(crate) fn apply(&self, item: ast::AssocItem) { + if let Some(ctx) = self.build_ctx() { + ctx.apply(item) + } + } + fn build_ctx(&self) -> Option> { + let db = self.source_scope.db; + let target_module = self.target_scope.module()?; + let source_module = self.source_scope.module()?; + + let substs = get_syntactic_substs(self.subst.1.clone()).unwrap_or_default(); + let generic_def: hir::GenericDef = self.subst.0.into(); + let substs_by_param: FxHashMap<_, _> = generic_def + .type_params(db) + .into_iter() + // this is a trait impl, so we need to skip the first type parameter -- this is a bit hacky + .skip(1) + // The actual list of trait type parameters may be longer than the one + // used in the `impl` block due to trailing default type parameters. + // For that case we extend the `substs` with an empty iterator so we + // can still hit those trailing values and check if they actually have + // a default type. If they do, go for that type from `hir` to `ast` so + // the resulting change can be applied correctly. + .zip(substs.into_iter().map(Some).chain(std::iter::repeat(None))) + .filter_map(|(k, v)| match v { + Some(v) => Some((k, v)), + None => { + let default = k.default(db)?; + Some(( + k, + ast::make::ty(&default.display_source_code(db, source_module.into()).ok()?), + )) + } + }) + .collect(); + + let res = Ctx { substs: substs_by_param, target_module, source_scope: self.source_scope }; + Some(res) + } +} + +struct Ctx<'a> { + substs: FxHashMap, + target_module: hir::Module, + source_scope: &'a SemanticsScope<'a>, +} + +impl<'a> Ctx<'a> { + fn apply(&self, item: ast::AssocItem) { + for event in item.syntax().preorder() { + let node = match event { + syntax::WalkEvent::Enter(_) => continue, + syntax::WalkEvent::Leave(it) => it, + }; + if let Some(path) = ast::Path::cast(node.clone()) { + self.transform_path(path); + } + } + } + fn transform_path(&self, path: ast::Path) -> Option<()> { + if path.qualifier().is_some() { + return None; + } + if path.segment().and_then(|s| s.param_list()).is_some() { + // don't try to qualify `Fn(Foo) -> Bar` paths, they are in prelude anyway + return None; + } + + let resolution = self.source_scope.speculative_resolve(&path)?; + + match resolution { + hir::PathResolution::TypeParam(tp) => { + if let Some(subst) = self.substs.get(&tp) { + ted::replace(path.syntax(), subst.clone_subtree().clone_for_update().syntax()) + } + } + hir::PathResolution::Def(def) => { + let found_path = + self.target_module.find_use_path(self.source_scope.db.upcast(), def)?; + let res = mod_path_to_ast(&found_path).clone_for_update(); + if let Some(args) = path.segment().and_then(|it| it.generic_arg_list()) { + if let Some(segment) = res.segment() { + let old = segment.get_or_create_generic_arg_list(); + ted::replace(old.syntax(), args.clone_subtree().syntax().clone_for_update()) + } + } + ted::replace(path.syntax(), res.syntax()) + } + hir::PathResolution::Local(_) + | hir::PathResolution::ConstParam(_) + | hir::PathResolution::SelfType(_) + | hir::PathResolution::Macro(_) + | hir::PathResolution::AssocItem(_) => (), + } + Some(()) + } +} + +// FIXME: It would probably be nicer if we could get this via HIR (i.e. get the +// trait ref, and then go from the types in the substs back to the syntax). +fn get_syntactic_substs(impl_def: ast::Impl) -> Option> { + let target_trait = impl_def.trait_()?; + let path_type = match target_trait { + ast::Type::PathType(path) => path, + _ => return None, + }; + let generic_arg_list = path_type.path()?.segment()?.generic_arg_list()?; + + let mut result = Vec::new(); + for generic_arg in generic_arg_list.generic_args() { + match generic_arg { + ast::GenericArg::TypeArg(type_arg) => result.push(type_arg.ty()?), + ast::GenericArg::AssocTypeArg(_) + | ast::GenericArg::LifetimeArg(_) + | ast::GenericArg::ConstArg(_) => (), + } + } + + Some(result) +} diff --git a/crates/ide_assists/src/utils.rs b/crates/ide_assists/src/utils.rs index 2e79a3aed..30128a24a 100644 --- a/crates/ide_assists/src/utils.rs +++ b/crates/ide_assists/src/utils.rs @@ -24,7 +24,7 @@ use syntax::{ use crate::{ assist_context::{AssistBuilder, AssistContext}, - ast_transform::AstTransform, + path_transform::PathTransform, }; pub(crate) fn unwrap_trivial_block(block: ast::BlockExpr) -> ast::Expr { @@ -133,7 +133,7 @@ pub fn add_trait_assoc_items_to_impl( ) -> (ast::Impl, ast::AssocItem) { let source_scope = sema.scope_for_def(trait_); - let transform = AstTransform { + let transform = PathTransform { subst: (trait_, impl_.clone()), source_scope: &source_scope, target_scope: &target_scope, -- cgit v1.2.3