Merge #4839

4839: `Go to Type Definition` hover action. r=matklad a=vsrs

![hover_actions_goto](https://user-images.githubusercontent.com/62505555/83335671-0122e380-a2b7-11ea-9922-fbdcfb11a7f3.gif)

This implementation supports things like `dyn Trait<SomeType>`, `-> impl Trait`, etc.

Co-authored-by: vsrs <vit@conrlab.com>

crates/ra_hir/src/code_model.rs

@@ -26,8 +26,8 @@ use hir_ty::{
     autoderef,
     display::{HirDisplayError, HirFormatter},
     expr::ExprValidator,
-    method_resolution, ApplicationTy, Canonical, InEnvironment, Substs, TraitEnvironment, Ty,
+    method_resolution, ApplicationTy, Canonical, GenericPredicate, InEnvironment, Substs,
-    TyDefId, TypeCtor,
+    TraitEnvironment, Ty, TyDefId, TypeCtor,
 };
 use ra_db::{CrateId, CrateName, Edition, FileId};
 use ra_prof::profile;
@@ -186,6 +186,22 @@ impl ModuleDef {
 
         module.visibility_of(db, self)
     }
+
+    pub fn name(self, db: &dyn HirDatabase) -> Option<Name> {
+        match self {
+            ModuleDef::Adt(it) => Some(it.name(db)),
+            ModuleDef::Trait(it) => Some(it.name(db)),
+            ModuleDef::Function(it) => Some(it.name(db)),
+            ModuleDef::EnumVariant(it) => Some(it.name(db)),
+            ModuleDef::TypeAlias(it) => Some(it.name(db)),
+
+            ModuleDef::Module(it) => it.name(db),
+            ModuleDef::Const(it) => it.name(db),
+            ModuleDef::Static(it) => it.name(db),
+
+            ModuleDef::BuiltinType(it) => Some(it.as_name()),
+        }
+    }
 }
 
 pub use hir_def::{
@@ -1359,6 +1375,27 @@ impl Type {
         Some(adt.into())
     }
 
+    pub fn as_dyn_trait(&self) -> Option<Trait> {
+        self.ty.value.dyn_trait().map(Into::into)
+    }
+
+    pub fn as_impl_traits(&self, db: &dyn HirDatabase) -> Option<Vec<Trait>> {
+        self.ty.value.impl_trait_bounds(db).map(|it| {
+            it.into_iter()
+                .filter_map(|pred| match pred {
+                    hir_ty::GenericPredicate::Implemented(trait_ref) => {
+                        Some(Trait::from(trait_ref.trait_))
+                    }
+                    _ => None,
+                })
+                .collect()
+        })
+    }
+
+    pub fn as_associated_type_parent_trait(&self, db: &dyn HirDatabase) -> Option<Trait> {
+        self.ty.value.associated_type_parent_trait(db).map(Into::into)
+    }
+
     // FIXME: provide required accessors such that it becomes implementable from outside.
     pub fn is_equal_for_find_impls(&self, other: &Type) -> bool {
         match (&self.ty.value, &other.ty.value) {
@@ -1380,6 +1417,80 @@ impl Type {
             ty: InEnvironment { value: ty, environment: self.ty.environment.clone() },
         }
     }
+
+    pub fn walk(&self, db: &dyn HirDatabase, mut cb: impl FnMut(Type)) {
+        // TypeWalk::walk for a Ty at first visits parameters and only after that the Ty itself.
+        // We need a different order here.
+
+        fn walk_substs(
+            db: &dyn HirDatabase,
+            type_: &Type,
+            substs: &Substs,
+            cb: &mut impl FnMut(Type),
+        ) {
+            for ty in substs.iter() {
+                walk_type(db, &type_.derived(ty.clone()), cb);
+            }
+        }
+
+        fn walk_bounds(
+            db: &dyn HirDatabase,
+            type_: &Type,
+            bounds: &[GenericPredicate],
+            cb: &mut impl FnMut(Type),
+        ) {
+            for pred in bounds {
+                match pred {
+                    GenericPredicate::Implemented(trait_ref) => {
+                        cb(type_.clone());
+                        walk_substs(db, type_, &trait_ref.substs, cb);
+                    }
+                    _ => (),
+                }
+            }
+        }
+
+        fn walk_type(db: &dyn HirDatabase, type_: &Type, cb: &mut impl FnMut(Type)) {
+            let ty = type_.ty.value.strip_references();
+            match ty {
+                Ty::Apply(ApplicationTy { ctor, parameters }) => {
+                    match ctor {
+                        TypeCtor::Adt(_) => {
+                            cb(type_.derived(ty.clone()));
+                        }
+                        TypeCtor::AssociatedType(_) => {
+                            if let Some(_) = ty.associated_type_parent_trait(db) {
+                                cb(type_.derived(ty.clone()));
+                            }
+                        }
+                        _ => (),
+                    }
+
+                    // adt params, tuples, etc...
+                    walk_substs(db, type_, parameters, cb);
+                }
+                Ty::Opaque(opaque_ty) => {
+                    if let Some(bounds) = ty.impl_trait_bounds(db) {
+                        walk_bounds(db, &type_.derived(ty.clone()), &bounds, cb);
+                    }
+
+                    walk_substs(db, type_, &opaque_ty.parameters, cb);
+                }
+                Ty::Placeholder(_) => {
+                    if let Some(bounds) = ty.impl_trait_bounds(db) {
+                        walk_bounds(db, &type_.derived(ty.clone()), &bounds, cb);
+                    }
+                }
+                Ty::Dyn(bounds) => {
+                    walk_bounds(db, &type_.derived(ty.clone()), bounds.as_ref(), cb);
+                }
+
+                _ => (),
+            }
+        }
+
+        walk_type(db, self, &mut cb);
+    }
 }
 
 impl HirDisplay for Type {

crates/ra_hir_ty/src/lib.rs

@@ -73,6 +73,7 @@ pub use lower::{
 pub use traits::{InEnvironment, Obligation, ProjectionPredicate, TraitEnvironment};
 
 pub use chalk_ir::{BoundVar, DebruijnIndex};
+use itertools::Itertools;
 
 /// A type constructor or type name: this might be something like the primitive
 /// type `bool`, a struct like `Vec`, or things like function pointers or
@@ -815,6 +816,11 @@ impl Ty {
         }
     }
 
+    /// If this is a `dyn Trait`, returns that trait.
+    pub fn dyn_trait(&self) -> Option<TraitId> {
+        self.dyn_trait_ref().map(|it| it.trait_)
+    }
+
     fn builtin_deref(&self) -> Option<Ty> {
         match self {
             Ty::Apply(a_ty) => match a_ty.ctor {
@@ -867,13 +873,56 @@ impl Ty {
         }
     }
 
-    /// If this is a `dyn Trait`, returns that trait.
+    pub fn impl_trait_bounds(&self, db: &dyn HirDatabase) -> Option<Vec<GenericPredicate>> {
-    pub fn dyn_trait(&self) -> Option<TraitId> {
         match self {
-            Ty::Dyn(predicates) => predicates.iter().find_map(|pred| match pred {
+            Ty::Opaque(opaque_ty) => {
-                GenericPredicate::Implemented(tr) => Some(tr.trait_),
+                let predicates = match opaque_ty.opaque_ty_id {
+                    OpaqueTyId::ReturnTypeImplTrait(func, idx) => {
+                        db.return_type_impl_traits(func).map(|it| {
+                            let data = (*it)
+                                .as_ref()
+                                .map(|rpit| rpit.impl_traits[idx as usize].bounds.clone());
+                            data.clone().subst(&opaque_ty.parameters)
+                        })
+                    }
+                };
+
+                predicates.map(|it| it.value)
+            }
+            Ty::Placeholder(id) => {
+                let generic_params = db.generic_params(id.parent);
+                let param_data = &generic_params.types[id.local_id];
+                match param_data.provenance {
+                    hir_def::generics::TypeParamProvenance::ArgumentImplTrait => {
+                        let predicates = db
+                            .generic_predicates_for_param(*id)
+                            .into_iter()
+                            .map(|pred| pred.value.clone())
+                            .collect_vec();
+
+                        Some(predicates)
+                    }
                     _ => None,
-            }),
+                }
+            }
+            _ => None,
+        }
+    }
+
+    pub fn associated_type_parent_trait(&self, db: &dyn HirDatabase) -> Option<TraitId> {
+        match self {
+            Ty::Apply(ApplicationTy { ctor: TypeCtor::AssociatedType(type_alias_id), .. }) => {
+                match type_alias_id.lookup(db.upcast()).container {
+                    AssocContainerId::TraitId(trait_id) => Some(trait_id),
+                    _ => None,
+                }
+            }
+            Ty::Projection(projection_ty) => {
+                match projection_ty.associated_ty.lookup(db.upcast()).container {
+                    AssocContainerId::TraitId(trait_id) => Some(trait_id),
+                    _ => None,
+                }
+            }
             _ => None,
         }
     }
@@ -1057,5 +1106,5 @@ pub struct ReturnTypeImplTraits {
 
 #[derive(Clone, PartialEq, Eq, Debug, Hash)]
 pub(crate) struct ReturnTypeImplTrait {
-    pub(crate) bounds: Binders<Vec<GenericPredicate>>,
+    pub bounds: Binders<Vec<GenericPredicate>>,
 }

crates/ra_ide/src/lib.rs

@@ -66,7 +66,7 @@ pub use crate::{
     display::{file_structure, FunctionSignature, NavigationTarget, StructureNode},
     expand_macro::ExpandedMacro,
     folding_ranges::{Fold, FoldKind},
-    hover::{HoverAction, HoverConfig, HoverResult},
+    hover::{HoverAction, HoverConfig, HoverGotoTypeData, HoverResult},
     inlay_hints::{InlayHint, InlayHintsConfig, InlayKind},
     references::{Declaration, Reference, ReferenceAccess, ReferenceKind, ReferenceSearchResult},
     runnables::{Runnable, RunnableKind, TestId},

crates/rust-analyzer/src/config.rs

@@ -296,6 +296,7 @@ impl Config {
             set(value, "/hoverActions/implementations", &mut self.hover.implementations);
             set(value, "/hoverActions/run", &mut self.hover.run);
             set(value, "/hoverActions/debug", &mut self.hover.debug);
+            set(value, "/hoverActions/gotoTypeDef", &mut self.hover.goto_type_def);
         } else {
             self.hover = HoverConfig::NO_ACTIONS;
         }

crates/rust-analyzer/src/main_loop/handlers.rs

@@ -18,8 +18,8 @@ use lsp_types::{
     TextDocumentIdentifier, Url, WorkspaceEdit,
 };
 use ra_ide::{
-    FileId, FilePosition, FileRange, HoverAction, Query, RangeInfo, Runnable, RunnableKind,
+    FileId, FilePosition, FileRange, HoverAction, HoverGotoTypeData, NavigationTarget, Query,
-    SearchScope, TextEdit,
+    RangeInfo, Runnable, RunnableKind, SearchScope, TextEdit,
 };
 use ra_prof::profile;
 use ra_project_model::TargetKind;
@@ -1150,6 +1150,23 @@ fn debug_single_command(runnable: &lsp_ext::Runnable) -> Command {
     }
 }
 
+fn goto_location_command(snap: &GlobalStateSnapshot, nav: &NavigationTarget) -> Option<Command> {
+    let value = if snap.config.client_caps.location_link {
+        let link = to_proto::location_link(snap, None, nav.clone()).ok()?;
+        to_value(link).ok()?
+    } else {
+        let range = FileRange { file_id: nav.file_id(), range: nav.range() };
+        let location = to_proto::location(snap, range).ok()?;
+        to_value(location).ok()?
+    };
+
+    Some(Command {
+        title: nav.name().to_string(),
+        command: "rust-analyzer.gotoLocation".into(),
+        arguments: Some(vec![value]),
+    })
+}
+
 fn to_command_link(command: Command, tooltip: String) -> lsp_ext::CommandLink {
     lsp_ext::CommandLink { tooltip: Some(tooltip), command }
 }
@@ -1180,13 +1197,13 @@ fn show_impl_command_link(
     None
 }
 
-fn to_runnable_action(
+fn runnable_action_links(
     snap: &GlobalStateSnapshot,
     file_id: FileId,
     runnable: Runnable,
 ) -> Option<lsp_ext::CommandLinkGroup> {
     let cargo_spec = CargoTargetSpec::for_file(&snap, file_id).ok()?;
-    if should_skip_target(&runnable, cargo_spec.as_ref()) {
+    if !snap.config.hover.runnable() || should_skip_target(&runnable, cargo_spec.as_ref()) {
         return None;
     }
 
@@ -1208,6 +1225,26 @@ fn to_runnable_action(
     })
 }
 
+fn goto_type_action_links(
+    snap: &GlobalStateSnapshot,
+    nav_targets: &[HoverGotoTypeData],
+) -> Option<lsp_ext::CommandLinkGroup> {
+    if !snap.config.hover.goto_type_def || nav_targets.is_empty() {
+        return None;
+    }
+
+    Some(lsp_ext::CommandLinkGroup {
+        title: Some("Go to ".into()),
+        commands: nav_targets
+            .iter()
+            .filter_map(|it| {
+                goto_location_command(snap, &it.nav)
+                    .map(|cmd| to_command_link(cmd, it.mod_path.clone()))
+            })
+            .collect(),
+    })
+}
+
 fn prepare_hover_actions(
     snap: &GlobalStateSnapshot,
     file_id: FileId,
@@ -1221,7 +1258,8 @@ fn prepare_hover_actions(
         .iter()
         .filter_map(|it| match it {
             HoverAction::Implementaion(position) => show_impl_command_link(snap, position),
-            HoverAction::Runnable(r) => to_runnable_action(snap, file_id, r.clone()),
+            HoverAction::Runnable(r) => runnable_action_links(snap, file_id, r.clone()),
+            HoverAction::GoToType(targets) => goto_type_action_links(snap, targets),
         })
         .collect()
 }

editors/code/package.json

@@ -510,6 +510,11 @@
                     "type": "boolean",
                     "default": true
                 },
+                "rust-analyzer.hoverActions.gotoTypeDef": {
+                    "markdownDescription": "Whether to show `Go to Type Definition` action. Only applies when `#rust-analyzer.hoverActions.enable#` is set.",
+                    "type": "boolean",
+                    "default": true
+                },
                 "rust-analyzer.linkedProjects": {
                     "markdownDescription": "Disable project auto-discovery in favor of explicitly specified set of projects.  \nElements must be paths pointing to Cargo.toml, rust-project.json, or JSON objects in rust-project.json format",
                     "type": "array",

editors/code/src/commands.ts

@@ -353,6 +353,20 @@ export function applyActionGroup(_ctx: Ctx): Cmd {
     };
 }
 
+export function gotoLocation(ctx: Ctx): Cmd {
+    return async (locationLink: lc.LocationLink) => {
+        const client = ctx.client;
+        if (client) {
+            const uri = client.protocol2CodeConverter.asUri(locationLink.targetUri);
+            let range = client.protocol2CodeConverter.asRange(locationLink.targetSelectionRange);
+            // collapse the range to a cursor position
+            range = range.with({ end: range.start });
+
+            await vscode.window.showTextDocument(uri, { selection: range });
+        }
+    };
+}
+
 export function resolveCodeAction(ctx: Ctx): Cmd {
     const client = ctx.client;
     return async (params: ra.ResolveCodeActionParams) => {

editors/code/src/config.ts

@@ -117,7 +117,7 @@ export class Config {
         return {
             engine: this.get<string>("debug.engine"),
             engineSettings: this.get<object>("debug.engineSettings"),
-            openUpDebugPane: this.get<boolean>("debug.openUpDebugPane"),
+            openDebugPane: this.get<boolean>("debug.openDebugPane"),
             sourceFileMap: sourceFileMap
         };
     }
@@ -135,6 +135,9 @@ export class Config {
         return {
             enable: this.get<boolean>("hoverActions.enable"),
             implementations: this.get<boolean>("hoverActions.implementations"),
+            run: this.get<boolean>("hoverActions.run"),
+            debug: this.get<boolean>("hoverActions.debug"),
+            gotoTypeDef: this.get<boolean>("hoverActions.gotoTypeDef"),
         };
     }
 }

editors/code/src/debug.ts

@@ -82,7 +82,7 @@ async function getDebugConfiguration(ctx: Ctx, runnable: ra.Runnable): Promise<v
     }
 
     debugOutput.clear();
-    if (ctx.config.debug.openUpDebugPane) {
+    if (ctx.config.debug.openDebugPane) {
         debugOutput.show(true);
     }
 

editors/code/src/main.ts

@@ -100,6 +100,7 @@ export async function activate(context: vscode.ExtensionContext) {
     ctx.registerCommand('applySnippetWorkspaceEdit', commands.applySnippetWorkspaceEditCommand);
     ctx.registerCommand('resolveCodeAction', commands.resolveCodeAction);
     ctx.registerCommand('applyActionGroup', commands.applyActionGroup);
+    ctx.registerCommand('gotoLocation', commands.gotoLocation);
 
     ctx.pushCleanup(activateTaskProvider(workspaceFolder));