hacking

crates/hir-analysis/src/lib.rs

@@ -67,7 +67,7 @@ pub struct Jar(
     ty::diagnostics::ImplTraitDefDiagAccumulator,
     ty::diagnostics::ImplDefDiagAccumulator,
     ty::diagnostics::FuncDefDiagAccumulator,
-    ty::CycleAccumulator,
+    ty::RecursiveAdtConstituentAccumulator,
 );
 
 pub trait HirAnalysisDb: salsa::DbWithJar<Jar> + HirDb {

crates/hir-analysis/src/ty/def_analysis.rs

@@ -43,9 +43,9 @@ use super::{
         GenericParamOwnerId,
     },
     visitor::{walk_ty, TyVisitor},
-    Cycle,
+    AdtRecursionConstituent,
 };
-use crate::ty::CycleAccumulator;
+use crate::ty::RecursiveAdtConstituentAccumulator;
 
 /// This function implements analysis for the ADT definition.
 /// The analysis includes the following:
@@ -66,9 +66,9 @@ pub fn analyze_adt(db: &dyn HirAnalysisDb, adt_ref: AdtRefId) {
         AdtDefDiagAccumulator::push(db, diag);
     }
 
-    // if let Some(RecursiveAdtRecord) = check_recursive_adt(db, adt_ref) {
-    //     CycleAccumulator::push(db, cycle);
-    // }
+    if let Some(cycle) = check_recursive_adt(db, adt_ref) {
+        RecursiveAdtConstituentAccumulator::push(db, cycle);
+    }
 }
 
 /// This function implements analysis for the trait definition.
@@ -702,7 +702,10 @@ impl<'db> Visitor for DefAnalyzer<'db> {
 }
 
 #[salsa::tracked(recovery_fn = check_recursive_adt_impl)]
-pub(crate) fn check_recursive_adt(db: &dyn HirAnalysisDb, adt: AdtRefId) -> Option<Cycle> {
+pub(crate) fn check_recursive_adt(
+    db: &dyn HirAnalysisDb,
+    adt: AdtRefId,
+) -> Option<AdtRecursionConstituent> {
     let adt_def = lower_adt(db, adt);
     for field in adt_def.fields(db) {
         for ty in field.iter_types(db) {
@@ -719,7 +722,7 @@ fn check_recursive_adt_impl(
     db: &dyn HirAnalysisDb,
     cycle: &salsa::Cycle,
     adt: AdtRefId,
-) -> Option<Cycle> {
+) -> Option<AdtRecursionConstituent> {
     let participants: FxHashSet<_> = cycle
         .participant_keys()
         .map(|key| check_recursive_adt::key_from_id(key.key_index()))
@@ -730,8 +733,12 @@ fn check_recursive_adt_impl(
         for (ty_idx, ty) in field.iter_types(db).enumerate() {
             for field_adt_ref in ty.collect_direct_adts(db) {
                 if participants.contains(&field_adt_ref) && participants.contains(&adt) {
-                    let cycle = Cycle::new(field_adt_ref, adt);
-                    return Some(cycle);
+                    let constituent = AdtRecursionConstituent::new(
+                        (adt, adt.name_span(db)),
+                        field_adt_ref,
+                        adt_def.variant_ty_span(db, field_idx, ty_idx),
+                    );
+                    return Some(constituent);
                 }
             }
         }

crates/hir-analysis/src/ty/diagnostics.rs

@@ -15,6 +15,7 @@ use crate::HirAnalysisDb;
 use super::{
     constraint::PredicateId,
     ty_def::{AdtRefId, Kind, TyId},
+    AdtRecursionConstituent,
 };
 
 use itertools::Itertools;
@@ -55,7 +56,7 @@ impl TyDiagCollection {
 pub enum TyLowerDiag {
     NotFullyAppliedType(DynLazySpan),
     InvalidTypeArgKind(DynLazySpan, String),
-    RecursiveType(Vec<(DynLazySpan, DynLazySpan)>),
+    RecursiveType(Vec<AdtRecursionConstituent>),
 
     UnboundTypeAliasParam {
         span: DynLazySpan,
@@ -114,7 +115,7 @@ impl TyLowerDiag {
         Self::InvalidTypeArgKind(span, msg)
     }
 
-    pub(super) fn recursive_type(constituents: Vec<(DynLazySpan, DynLazySpan)>) -> Self {
+    pub(super) fn recursive_type(constituents: Vec<AdtRecursionConstituent>) -> Self {
         Self::RecursiveType(constituents)
     }
 
@@ -232,11 +233,16 @@ impl TyLowerDiag {
             Self::RecursiveType(constituents) => {
                 let mut diags = vec![];
 
-                for (primary_span, field_span) in constituents {
+                for AdtRecursionConstituent {
+                    from,
+                    to,
+                    field_span,
+                } in constituents
+                {
                     diags.push(SubDiagnostic::new(
                         LabelStyle::Primary,
                         "recursive type definition".to_string(),
-                        primary_span.resolve(db),
+                        from.1.resolve(db),
                     ));
                     diags.push(SubDiagnostic::new(
                         LabelStyle::Secondary,

crates/hir-analysis/src/ty/mod.rs

@@ -1,5 +1,12 @@
+use std::collections::LinkedList;
+
 use crate::HirAnalysisDb;
-use hir::{analysis_pass::ModuleAnalysisPass, hir_def::TopLevelMod};
+use hir::{
+    analysis_pass::ModuleAnalysisPass,
+    hir_def::{FieldDef, FieldDefListId, TopLevelMod},
+    span::DynLazySpan,
+};
+use indexmap::{indexmap, indexset, IndexMap};
 
 use self::{
     def_analysis::{
@@ -11,7 +18,7 @@ use self::{
         ImplTraitDefDiagAccumulator, TraitDefDiagAccumulator, TyDiagCollection, TyLowerDiag,
         TypeAliasDefDiagAccumulator,
     },
-    ty_def::AdtRefId,
+    ty_def::{AdtField, AdtRefId},
 };
 
 pub mod constraint_solver;
@@ -64,9 +71,9 @@ impl<'db> ModuleAnalysisPass for TypeDefAnalysisPass<'db> {
         let mut cycles = vec![];
         let mut diags = adts
             .flat_map(|adt| {
-                cycles.append(&mut analyze_adt::accumulated::<CycleAccumulator>(
-                    self.db, adt,
-                ));
+                cycles.append(&mut analyze_adt::accumulated::<
+                    RecursiveAdtConstituentAccumulator,
+                >(self.db, adt));
                 analyze_adt::accumulated::<AdtDefDiagAccumulator>(self.db, adt).into_iter()
             })
             .map(|diag| diag.to_voucher())
@@ -75,75 +82,67 @@ impl<'db> ModuleAnalysisPass for TypeDefAnalysisPass<'db> {
         if cycles.is_empty() {
             diags
         } else {
-            merge_cycles(&mut cycles);
-            // panic!("{:#?}", cycles);
-            let mut recursive_diags = cycles
-                .iter()
-                .map(|cycle| {
-                    let span = cycle.path[0].0.name_span(self.db);
-                    TyDiagCollection::Ty(TyLowerDiag::RecursiveType).to_voucher()
-                })
-                .collect();
-            diags.append(&mut recursive_diags);
+            diags.append(
+                &mut recursive_adt_diags(&cycles)
+                    .into_iter()
+                    .map(|constituent| TyDiagCollection::Ty(constituent).to_voucher())
+                    .collect(),
+            );
             diags
         }
     }
 }
 
 #[salsa::accumulator]
-pub struct CycleAccumulator(pub(super) Cycle);
-
-#[derive(Clone, Debug, Eq, PartialEq)]
-pub struct Cycle {
-    pub path: Vec<(AdtRefId, AdtRefId)>,
-}
-
-impl Cycle {
-    pub fn new(a: AdtRefId, b: AdtRefId) -> Self {
-        Self { path: vec![(a, b)] }
-    }
-
-    pub fn merge(&mut self, other: &mut Self) {
-        assert_eq!(self.end(), other.start());
-        self.path.append(&mut other.path);
-    }
-
-    pub fn is_complete(&self) -> bool {
-        self.start() == self.end()
-    }
+pub struct RecursiveAdtConstituentAccumulator(pub(super) AdtRecursionConstituent);
+
+pub fn recursive_adt_diags(constituents: &[AdtRecursionConstituent]) -> Vec<TyLowerDiag> {
+    let mut diags = vec![];
+    let mut unified_constituents = indexset! {};
+
+    while let Some(mut cur) =
+        (0..constituents.len()).find(|index| !unified_constituents.contains(index))
+    {
+        unified_constituents.insert(cur);
+        let mut recursion = vec![cur];
+
+        while constituents[recursion[0]].from.0 != constituents[cur].to {
+            if let Some(index) = (0..constituents.len()).find(|index| {
+                !unified_constituents.contains(index)
+                    && constituents[cur].to == constituents[*index].from.0
+            }) {
+                cur = index;
+                unified_constituents.insert(index);
+                recursion.push(index);
+            } else {
+                break;
+            };
+        }
 
-    pub fn start(&self) -> AdtRefId {
-        self.path[0].0
+        diags.push(TyLowerDiag::recursive_type(
+            recursion
+                .iter()
+                .map(|index| constituents[*index].to_owned())
+                .collect(),
+        ));
     }
 
-    pub fn end(&self) -> AdtRefId {
-        self.path[self.path.len() - 1].1
-    }
+    diags
 }
 
-fn merge_cycles(cycles: &mut Vec<Cycle>) {
-    let mut complete = false;
-
-    while !complete {
-        complete = true;
-
-        for i in 0..cycles.len() {
-            if !cycles[i].is_complete() {
-                complete = false;
-
-                for j in 0..cycles.len() {
-                    if cycles[i].end() == cycles[j].start() {
-                        let mut j_clone = cycles[j].clone();
-                        cycles[i].merge(&mut j_clone);
-                        cycles.remove(j);
-                        break;
-                    }
-                }
+#[derive(Clone, Debug, Eq, PartialEq, Hash)]
+pub struct AdtRecursionConstituent {
+    pub from: (AdtRefId, DynLazySpan),
+    pub to: AdtRefId,
+    pub field_span: DynLazySpan,
+}
 
-                if !complete {
-                    break;
-                }
-            }
+impl AdtRecursionConstituent {
+    pub fn new(from: (AdtRefId, DynLazySpan), to: AdtRefId, field_span: DynLazySpan) -> Self {
+        Self {
+            from,
+            to,
+            field_span,
         }
     }
 }

crates/uitest/fixtures/ty/def/recursive_type.snap

@@ -7,27 +7,34 @@ error[3-0002]: recursive type is not allowed
   ┌─ recursive_type.fe:1:12
   │
 1 │ pub struct S1 {
-  │            ^^
-  │            │
-  │            recursive type definition
-  │            recursion occurs here
+  │            ^^ recursive type definition
+2 │     s: S1
+  │        -- recursion occurs here
 
 error[3-0002]: recursive type is not allowed
-  ┌─ recursive_type.fe:5:12
-  │
-5 │ pub struct S2 {
-  │            ^^
-  │            │
-  │            recursive type definition
-  │            recursion occurs here
+   ┌─ recursive_type.fe:5:12
+   │
+ 5 │ pub struct S2 {
+   │            ^^ recursive type definition
+ 6 │     s: S3
+   │        -- recursion occurs here
+   ·
+ 9 │ pub struct S3 {
+   │            ^^ recursive type definition
+10 │     s: S4
+   │        -- recursion occurs here
+   ·
+13 │ pub struct S4 {
+   │            ^^ recursive type definition
+14 │     s: S2
+   │        -- recursion occurs here
 
 error[3-0002]: recursive type is not allowed
    ┌─ recursive_type.fe:22:12
    │
 22 │ pub struct S6 {
-   │            ^^
-   │            │
-   │            recursive type definition
-   │            recursion occurs here
+   │            ^^ recursive type definition
+23 │     s: S5<S6>
+   │        ------ recursion occurs here
 
 

crates/uitest/fixtures/ty/def/recursive_type2.fe

@@ -7,7 +7,7 @@ pub struct B {
 }
 
 pub struct C {
-    // a: A,
+    a: A,
     d: D 
 }
 

crates/uitest/fixtures/ty/def/recursive_type2.snap

@@ -4,12 +4,21 @@ expression: diags
 input_file: crates/uitest/fixtures/ty/def/recursive_type2.fe
 ---
 error[3-0002]: recursive type is not allowed
-  ┌─ recursive_type2.fe:1:12
-  │
-1 │ pub struct A {
-  │            ^
-  │            │
-  │            recursive type definition
-  │            recursion occurs here
+   ┌─ recursive_type2.fe:1:12
+   │
+ 1 │ pub struct A {
+   │            ^ recursive type definition
+ 2 │     b: B 
+   │        - recursion occurs here
+   ·
+ 5 │ pub struct B {
+   │            ^ recursive type definition
+ 6 │     c: C
+   │        - recursion occurs here
+   ·
+ 9 │ pub struct C {
+   │            ^ recursive type definition
+10 │     a: A,
+   │        - recursion occurs here