Merge #8127

8127: Add label completion r=Veykril a=Veykril



Co-authored-by: Lukas Wirth <lukastw97@gmail.com>

crates/hir/src/lib.rs

@@ -2199,6 +2199,7 @@ pub enum ScopeDef {
     ImplSelfType(Impl),
     AdtSelfType(Adt),
     Local(Local),
+    Label(Label),
     Unknown,
 }
 

crates/hir/src/semantics.rs

@@ -839,6 +839,10 @@ impl<'a> SemanticsScope<'a> {
                     let parent = resolver.body_owner().unwrap();
                     ScopeDef::Local(Local { parent, pat_id })
                 }
+                resolver::ScopeDef::Label(label_id) => {
+                    let parent = resolver.body_owner().unwrap();
+                    ScopeDef::Label(Label { parent, label_id })
+                }
             };
             f(name, def)
         })

crates/hir_def/src/body/scope.rs

@@ -8,7 +8,7 @@ use rustc_hash::FxHashMap;
 use crate::{
     body::Body,
     db::DefDatabase,
-    expr::{Expr, ExprId, Pat, PatId, Statement},
+    expr::{Expr, ExprId, LabelId, Pat, PatId, Statement},
     BlockId, DefWithBodyId,
 };
 
@@ -40,6 +40,7 @@ impl ScopeEntry {
 pub struct ScopeData {
     parent: Option<ScopeId>,
     block: Option<BlockId>,
+    label: Option<(LabelId, Name)>,
     entries: Vec<ScopeEntry>,
 }
 
@@ -67,6 +68,11 @@ impl ExprScopes {
         self.scopes[scope].block
     }
 
+    /// If `scope` refers to a labeled expression scope, returns the corresponding `Label`.
+    pub fn label(&self, scope: ScopeId) -> Option<(LabelId, Name)> {
+        self.scopes[scope].label.clone()
+    }
+
     pub fn scope_chain(&self, scope: Option<ScopeId>) -> impl Iterator<Item = ScopeId> + '_ {
         std::iter::successors(scope, move |&scope| self.scopes[scope].parent)
     }
@@ -85,15 +91,34 @@ impl ExprScopes {
     }
 
     fn root_scope(&mut self) -> ScopeId {
-        self.scopes.alloc(ScopeData { parent: None, block: None, entries: vec![] })
+        self.scopes.alloc(ScopeData { parent: None, block: None, label: None, entries: vec![] })
     }
 
     fn new_scope(&mut self, parent: ScopeId) -> ScopeId {
-        self.scopes.alloc(ScopeData { parent: Some(parent), block: None, entries: vec![] })
+        self.scopes.alloc(ScopeData {
+            parent: Some(parent),
+            block: None,
+            label: None,
+            entries: vec![],
+        })
     }
 
-    fn new_block_scope(&mut self, parent: ScopeId, block: BlockId) -> ScopeId {
-        self.scopes.alloc(ScopeData { parent: Some(parent), block: Some(block), entries: vec![] })
+    fn new_labeled_scope(&mut self, parent: ScopeId, label: Option<(LabelId, Name)>) -> ScopeId {
+        self.scopes.alloc(ScopeData { parent: Some(parent), block: None, label, entries: vec![] })
+    }
+
+    fn new_block_scope(
+        &mut self,
+        parent: ScopeId,
+        block: BlockId,
+        label: Option<(LabelId, Name)>,
+    ) -> ScopeId {
+        self.scopes.alloc(ScopeData {
+            parent: Some(parent),
+            block: Some(block),
+            label,
+            entries: vec![],
+        })
     }
 
     fn add_bindings(&mut self, body: &Body, scope: ScopeId, pat: PatId) {
@@ -144,21 +169,33 @@ fn compute_block_scopes(
 }
 
 fn compute_expr_scopes(expr: ExprId, body: &Body, scopes: &mut ExprScopes, scope: ScopeId) {
+    let make_label =
+        |label: &Option<_>| label.map(|label| (label, body.labels[label].name.clone()));
+
     scopes.set_scope(expr, scope);
     match &body[expr] {
-        Expr::Block { statements, tail, id, .. } => {
-            let scope = scopes.new_block_scope(scope, *id);
+        Expr::Block { statements, tail, id, label } => {
+            let scope = scopes.new_block_scope(scope, *id, make_label(label));
             // Overwrite the old scope for the block expr, so that every block scope can be found
             // via the block itself (important for blocks that only contain items, no expressions).
             scopes.set_scope(expr, scope);
-            compute_block_scopes(&statements, *tail, body, scopes, scope);
+            compute_block_scopes(statements, *tail, body, scopes, scope);
         }
-        Expr::For { iterable, pat, body: body_expr, .. } => {
+        Expr::For { iterable, pat, body: body_expr, label } => {
             compute_expr_scopes(*iterable, body, scopes, scope);
-            let scope = scopes.new_scope(scope);
+            let scope = scopes.new_labeled_scope(scope, make_label(label));
             scopes.add_bindings(body, scope, *pat);
             compute_expr_scopes(*body_expr, body, scopes, scope);
         }
+        Expr::While { condition, body: body_expr, label } => {
+            let scope = scopes.new_labeled_scope(scope, make_label(label));
+            compute_expr_scopes(*condition, body, scopes, scope);
+            compute_expr_scopes(*body_expr, body, scopes, scope);
+        }
+        Expr::Loop { body: body_expr, label } => {
+            let scope = scopes.new_labeled_scope(scope, make_label(label));
+            compute_expr_scopes(*body_expr, body, scopes, scope);
+        }
         Expr::Lambda { args, body: body_expr, .. } => {
             let scope = scopes.new_scope(scope);
             scopes.add_params_bindings(body, scope, &args);

crates/hir_def/src/resolver.rs

@@ -12,7 +12,7 @@ use crate::{
     body::scope::{ExprScopes, ScopeId},
     builtin_type::BuiltinType,
     db::DefDatabase,
-    expr::{ExprId, PatId},
+    expr::{ExprId, LabelId, PatId},
     generics::GenericParams,
     item_scope::{BuiltinShadowMode, BUILTIN_SCOPE},
     nameres::DefMap,
@@ -409,6 +409,7 @@ pub enum ScopeDef {
     AdtSelfType(AdtId),
     GenericParam(GenericParamId),
     Local(PatId),
+    Label(LabelId),
 }
 
 impl Scope {
@@ -470,6 +471,9 @@ impl Scope {
                 f(name![Self], ScopeDef::AdtSelfType(*i));
             }
             Scope::ExprScope(scope) => {
+                if let Some((label, name)) = scope.expr_scopes.label(scope.scope_id) {
+                    f(name.clone(), ScopeDef::Label(label))
+                }
                 scope.expr_scopes.entries(scope.scope_id).iter().for_each(|e| {
                     f(e.name().clone(), ScopeDef::Local(e.pat()));
                 });

crates/ide_completion/src/completions/lifetime.rs

@@ -1,4 +1,4 @@
-//! Completes lifetimes.
+//! Completes lifetimes and labels.
 use hir::ScopeDef;
 
 use crate::{completions::Completions, context::CompletionContext};
@@ -29,6 +29,18 @@ pub(crate) fn complete_lifetime(acc: &mut Completions, ctx: &CompletionContext)
     }
 }
 
+/// Completes labels.
+pub(crate) fn complete_label(acc: &mut Completions, ctx: &CompletionContext) {
+    if !ctx.is_label_ref {
+        return;
+    }
+    ctx.scope.process_all_names(&mut |name, res| {
+        if let ScopeDef::Label(_) = res {
+            acc.add_resolution(ctx, name.to_string(), &res);
+        }
+    });
+}
+
 #[cfg(test)]
 mod tests {
     use expect_test::{expect, Expect};
@@ -178,4 +190,96 @@ fn foo<'footime, 'lifetime: 'a$0>() {}
             "#]],
         );
     }
+
+    #[test]
+    fn complete_label_in_loop() {
+        check(
+            r#"
+fn foo() {
+    'foop: loop {
+        break '$0
+    }
+}
+"#,
+            expect![[r#"
+                lb 'foop
+            "#]],
+        );
+        check(
+            r#"
+fn foo() {
+    'foop: loop {
+        continue '$0
+    }
+}
+"#,
+            expect![[r#"
+                lb 'foop
+            "#]],
+        );
+    }
+
+    #[test]
+    fn complete_label_in_block_nested() {
+        check(
+            r#"
+fn foo() {
+    'foop: {
+        'baap: {
+            break '$0
+        }
+    }
+}
+"#,
+            expect![[r#"
+                lb 'baap
+                lb 'foop
+            "#]],
+        );
+    }
+
+    #[test]
+    fn complete_label_in_loop_with_value() {
+        check(
+            r#"
+fn foo() {
+    'foop: loop {
+        break '$0 i32;
+    }
+}
+"#,
+            expect![[r#"
+                lb 'foop
+            "#]],
+        );
+    }
+
+    #[test]
+    fn complete_label_in_while_cond() {
+        check(
+            r#"
+fn foo() {
+    'outer: while { 'inner: loop { break '$0 } } {}
+}
+"#,
+            expect![[r#"
+                lb 'inner
+                lb 'outer
+            "#]],
+        );
+    }
+
+    #[test]
+    fn complete_label_in_for_iterable() {
+        check(
+            r#"
+fn foo() {
+    'outer: for _ in [{ 'inner: loop { break '$0 } }] {}
+}
+"#,
+            expect![[r#"
+                lb 'inner
+            "#]],
+        );
+    }
 }

crates/ide_completion/src/context.rs

@@ -53,6 +53,7 @@ pub(crate) struct CompletionContext<'a> {
     /// FIXME: `ActiveParameter` is string-based, which is very very wrong
     pub(super) active_parameter: Option<ActiveParameter>,
     pub(super) is_param: bool,
+    pub(super) is_label_ref: bool,
     /// If a name-binding or reference to a const in a pattern.
     /// Irrefutable patterns (like let) are excluded.
     pub(super) is_pat_binding_or_const: bool,
@@ -155,6 +156,7 @@ impl<'a> CompletionContext<'a> {
             record_field_syntax: None,
             impl_def: None,
             active_parameter: ActiveParameter::at(db, position),
+            is_label_ref: false,
             is_param: false,
             is_pat_binding_or_const: false,
             is_irrefutable_pat_binding: false,
@@ -468,12 +470,24 @@ impl<'a> CompletionContext<'a> {
     ) {
         self.lifetime_syntax =
             find_node_at_offset(original_file, lifetime.syntax().text_range().start());
-        if lifetime.syntax().parent().map_or(false, |p| p.kind() != syntax::SyntaxKind::ERROR) {
-            self.lifetime_allowed = true;
-        }
-        if let Some(_) = lifetime.syntax().parent().and_then(ast::LifetimeParam::cast) {
-            self.lifetime_param_syntax =
-                self.sema.find_node_at_offset_with_macros(original_file, offset);
+        if let Some(parent) = lifetime.syntax().parent() {
+            if parent.kind() == syntax::SyntaxKind::ERROR {
+                return;
+            }
+
+            match_ast! {
+                match parent {
+                    ast::LifetimeParam(_it) => {
+                        self.lifetime_allowed = true;
+                        self.lifetime_param_syntax =
+                            self.sema.find_node_at_offset_with_macros(original_file, offset);
+                    },
+                    ast::BreakExpr(_it) => self.is_label_ref = true,
+                    ast::ContinueExpr(_it) => self.is_label_ref = true,
+                    ast::Label(_it) => (),
+                    _ => self.lifetime_allowed = true,
+                }
+            }
         }
     }
 

crates/ide_completion/src/lib.rs

@@ -131,6 +131,7 @@ pub fn completions(
     completions::mod_::complete_mod(&mut acc, &ctx);
     completions::flyimport::import_on_the_fly(&mut acc, &ctx);
     completions::lifetime::complete_lifetime(&mut acc, &ctx);
+    completions::lifetime::complete_label(&mut acc, &ctx);
 
     Some(acc)
 }

crates/ide_completion/src/render.rs

@@ -219,6 +219,7 @@ impl<'a> Render<'a> {
                 hir::GenericParam::ConstParam(_) => SymbolKind::ConstParam,
             }),
             ScopeDef::Local(..) => CompletionItemKind::SymbolKind(SymbolKind::Local),
+            ScopeDef::Label(..) => CompletionItemKind::SymbolKind(SymbolKind::Label),
             ScopeDef::AdtSelfType(..) | ScopeDef::ImplSelfType(..) => {
                 CompletionItemKind::SymbolKind(SymbolKind::SelfParam)
             }