[ty] Reduce size of TypeInference (#19435)

crates/ty_python_semantic/src/types.rs

@@ -104,7 +104,10 @@ pub fn check_types(db: &dyn Db, file: File) -> Vec<Diagnostic> {
 
     for scope_id in index.scope_ids() {
         let result = infer_scope_types(db, scope_id);
-        diagnostics.extend(result.diagnostics());
+
+        if let Some(scope_diagnostics) = result.diagnostics() {
+            diagnostics.extend(scope_diagnostics);
+        }
     }
 
     diagnostics.extend_diagnostics(
@@ -116,7 +119,7 @@ pub fn check_types(db: &dyn Db, file: File) -> Vec<Diagnostic> {
 
     check_suppressions(db, file, &mut diagnostics);
 
-    diagnostics.into_vec()
+    diagnostics.into_diagnostics()
 }
 
 /// Infer the type of a binding.

crates/ty_python_semantic/src/types/context.rs

@@ -32,7 +32,7 @@ use crate::{
 /// ## Consuming
 /// It's important that the context is explicitly consumed before dropping by calling
 /// [`InferContext::finish`] and the returned diagnostics must be stored
-/// on the current [`TypeInference`](super::infer::TypeInference) result.
+/// on the current [`TypeInferenceBuilder`](super::infer::TypeInferenceBuilder) result.
 pub(crate) struct InferContext<'db, 'ast> {
     db: &'db dyn Db,
     scope: ScopeId<'db>,

crates/ty_python_semantic/src/types/diagnostic.rs

@@ -1671,18 +1671,26 @@ impl TypeCheckDiagnostics {
         self.diagnostics.shrink_to_fit();
     }
 
-    pub(crate) fn into_vec(self) -> Vec<Diagnostic> {
+    pub(crate) fn into_diagnostics(self) -> Vec<Diagnostic> {
         self.diagnostics
     }
 
+    pub(crate) fn is_empty(&self) -> bool {
+        self.diagnostics.is_empty() && self.used_suppressions.is_empty()
+    }
+
     pub fn iter(&self) -> std::slice::Iter<'_, Diagnostic> {
-        self.diagnostics.iter()
+        self.diagnostics().iter()
+    }
+
+    fn diagnostics(&self) -> &[Diagnostic] {
+        self.diagnostics.as_slice()
     }
 }
 
 impl std::fmt::Debug for TypeCheckDiagnostics {
     fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
-        self.diagnostics.fmt(f)
+        self.diagnostics().fmt(f)
     }
 }
 
@@ -1691,7 +1699,7 @@ impl IntoIterator for TypeCheckDiagnostics {
     type IntoIter = std::vec::IntoIter<Diagnostic>;
 
     fn into_iter(self) -> Self::IntoIter {
-        self.diagnostics.into_iter()
+        self.into_diagnostics().into_iter()
     }
 }
 
@@ -1699,8 +1707,9 @@ impl<'a> IntoIterator for &'a TypeCheckDiagnostics {
     type Item = &'a Diagnostic;
     type IntoIter = std::slice::Iter<'a, Diagnostic>;
 
+    #[inline]
     fn into_iter(self) -> Self::IntoIter {
-        self.diagnostics.iter()
+        self.iter()
     }
 }