Remove fields from ClassInner

Summary:
Remove the `fields` field from `ClassInner` and the `fields` parameter
from `Class::new()`. Remove all delegating field accessor methods from
`Class` (fields, contains, is_field_annotated, is_field_initialized_on_class,
field_decl_range, field_docstring_range, class_body_fields).

All callers now use `get_class_fields()` via AnswersSolver (for solver
code paths) or `Bindings::get_class_fields()` / `Transaction::get_class_fields()`
(for external callers like LSP, Pysa, Query).

Also migrates get_class_field_map in classdef.rs and the test_fields
test in enums.rs.

Performance (median of 3 opt-clang-thinlto runs, baseline=parent of stack):

PyTorch:

| metric | baseline | this diff | cumulative |
|--------|----------|-----------|------------|
| cpu    |   40.65s |    40.83s |      +0.4% |
| wall   |    2.24s |     2.22s |      -0.9% |
| maxrss |   0.93GB |    0.90GB |      -3.2% |

Reviewed By: yangdanny97

Differential Revision: D96515736

fbshipit-source-id: 867ef12348e8ec69f5d63acf021321cf323b00c2

Author: samwgoldman

crates/pyrefly_types/src/class.rs

@@ -190,6 +190,13 @@ impl ClassFields {
     }
 }
 
+/// Align to a cache line to prevent false sharing. `ClassInner` is stored
+/// behind `Arc` and accessed concurrently from multiple threads during
+/// type checking. Without alignment, multiple `Arc<ClassInner>` allocations
+/// can land on the same cache line, causing cross-thread invalidation
+/// traffic when any of them are accessed (even read-only, due to the Arc
+/// refcount on adjacent allocations).
+#[repr(align(64))]
 struct ClassInner {
     def_index: ClassDefIndex,
     qname: QName,
@@ -198,7 +205,6 @@ struct ClassInner {
     /// when computing the class tparams). Whenever it is `None`, there will be a corresponding
     /// `KeyTParams` / `BindingTParams` pair to compute the class tparams.
     precomputed_tparams: Option<Arc<TParams>>,
-    fields: ClassFields,
 }
 
 impl Debug for ClassInner {
@@ -269,20 +275,14 @@ impl Class {
         parent: NestingContext,
         module: Module,
         precomputed_tparams: Option<Arc<TParams>>,
-        fields: ClassFields,
     ) -> Self {
         Self(Arc::new(ClassInner {
             def_index,
             qname: QName::new(name, parent, module),
             precomputed_tparams,
-            fields,
         }))
     }
 
-    pub fn contains(&self, name: &Name) -> bool {
-        self.0.fields.contains(name)
-    }
-
     pub fn range(&self) -> TextRange {
         self.0.qname.range()
     }
@@ -319,30 +319,6 @@ impl Class {
         self.0.qname.module()
     }
 
-    pub fn fields(&self) -> impl ExactSizeIterator<Item = &Name> {
-        self.0.fields.fields()
-    }
-
-    pub fn class_body_fields(&self) -> impl Iterator<Item = &Name> {
-        self.0.fields.class_body_fields()
-    }
-
-    pub fn is_field_annotated(&self, name: &Name) -> bool {
-        self.0.fields.is_field_annotated(name)
-    }
-
-    pub fn is_field_initialized_on_class(&self, name: &Name) -> bool {
-        self.0.fields.is_field_initialized_on_class(name)
-    }
-
-    pub fn field_decl_range(&self, name: &Name) -> Option<TextRange> {
-        self.0.fields.field_decl_range(name)
-    }
-
-    pub fn field_docstring_range(&self, name: &Name) -> Option<TextRange> {
-        self.0.fields.field_docstring_range(name)
-    }
-
     pub fn has_qname(&self, module: &str, parent: &NestingContext, name: &str) -> bool {
         self.0.qname.module_name().as_str() == module
             && self.0.qname.parent() == parent

crates/pyrefly_types/src/display.rs

@@ -1128,7 +1128,6 @@ pub mod tests {
     use crate::callable::Required;
     use crate::class::Class;
     use crate::class::ClassDefIndex;
-    use crate::class::ClassFields;
     use crate::class::ClassType;
     use crate::heap::TypeHeap;
     use crate::literal::Lit;
@@ -1162,7 +1161,6 @@ pub mod tests {
             NestingContext::toplevel(),
             mi,
             None,
-            ClassFields::default(),
         )
     }
 

crates/pyrefly_types/src/type_output.rs

@@ -192,7 +192,6 @@ mod tests {
     use super::*;
     use crate::class::Class;
     use crate::class::ClassDefIndex;
-    use crate::class::ClassFields;
     use crate::class::ClassType;
     use crate::literal::LitEnum;
     use crate::literal::LitStyle;
@@ -217,7 +216,6 @@ mod tests {
             NestingContext::toplevel(),
             mi,
             None,
-            ClassFields::default(),
         )
     }
 

pyrefly/lib/alt/class/classdef.rs

@@ -72,19 +72,12 @@ impl<'a, Ans: LookupAnswer> AnswersSolver<'a, Ans> {
         } else {
             Some(self.calculate_class_tparams_no_legacy(name, x.type_params.as_deref(), errors))
         };
-        let fields = self
-            .bindings()
-            .metadata()
-            .get_class(def_index)
-            .fields
-            .clone();
         Class::new(
             def_index,
             x.name.clone(),
             parent.dupe(),
             self.module().dupe(),
             precomputed_tparams,
-            fields,
         )
     }
 
@@ -94,19 +87,12 @@ impl<'a, Ans: LookupAnswer> AnswersSolver<'a, Ans> {
         name: &Identifier,
         parent: &NestingContext,
     ) -> Class {
-        let fields = self
-            .bindings()
-            .metadata()
-            .get_class(def_index)
-            .fields
-            .clone();
         Class::new(
             def_index,
             name.clone(),
             parent.dupe(),
             self.module().dupe(),
             Some(Arc::new(TParams::default())),
-            fields,
         )
     }
 
@@ -131,10 +117,12 @@ impl<'a, Ans: LookupAnswer> AnswersSolver<'a, Ans> {
     }
 
     pub fn get_class_field_map(&self, cls: &Class) -> SmallMap<Name, Arc<ClassField>> {
-        let fields = cls.fields();
-        let mut map = SmallMap::with_capacity(fields.len());
+        let Some(class_fields) = self.get_class_fields(cls) else {
+            return SmallMap::new();
+        };
+        let mut map = SmallMap::with_capacity(class_fields.len());
 
-        for name in fields {
+        for name in class_fields.names() {
             let key = KeyClassField(cls.index(), name.clone());
             if let Some(field) = self.get_from_class(cls, &key) {
                 map.insert(name.clone(), field);

pyrefly/lib/alt/solve.rs

@@ -2366,7 +2366,9 @@ impl<'a, Ans: LookupAnswer> AnswersSolver<'a, Ans> {
             let Some(owner) = class_binding.0.as_ref() else {
                 return;
             };
-            if owner.contains(&expect.attr.id)
+            if self
+                .get_class_fields(owner)
+                .is_some_and(|f| f.contains(&expect.attr.id))
                 && self.is_subset_eq(
                     &value_type,
                     &self.union(

pyrefly/lib/test/enums.rs

@@ -24,8 +24,10 @@ class E(enum.Enum):
         "#,
     );
     let cls = get_class("E", &handle, &state);
-    let fields = cls
-        .fields()
+    let bindings = state.transaction().get_bindings(&handle).unwrap();
+    let class_fields = bindings.get_class_fields(cls.index()).unwrap();
+    let fields = class_fields
+        .names()
         .map(|f| f.as_str())
         .sorted()
         .collect::<Vec<_>>();