[red-knot] simplify union size limit handling (#17429)

Author: carljm

crates/red_knot_python_semantic/src/types/builder.rs

@@ -97,14 +97,13 @@ impl<'db> UnionBuilder<'db> {
             // means we shouldn't add it. Otherwise, add a new `UnionElement::StringLiterals`
             // containing it.
             Type::StringLiteral(literal) => {
-                let mut too_large = false;
                 let mut found = false;
                 for element in &mut self.elements {
                     match element {
                         UnionElement::StringLiterals(literals) => {
                             if literals.len() >= MAX_UNION_LITERALS {
-                                too_large = true;
-                                break;
+                                let replace_with = KnownClass::Str.to_instance(self.db);
+                                return self.add(replace_with);
                             }
                             literals.insert(literal);
                             found = true;
@@ -116,10 +115,6 @@ impl<'db> UnionBuilder<'db> {
                         _ => {}
                     }
                 }
-                if too_large {
-                    let replace_with = KnownClass::Str.to_instance(self.db);
-                    return self.add(replace_with);
-                }
                 if !found {
                     self.elements
                         .push(UnionElement::StringLiterals(FxOrderSet::from_iter([
@@ -130,13 +125,12 @@ impl<'db> UnionBuilder<'db> {
             // Same for bytes literals as for string literals, above.
             Type::BytesLiteral(literal) => {
                 let mut found = false;
-                let mut too_large = false;
                 for element in &mut self.elements {
                     match element {
                         UnionElement::BytesLiterals(literals) => {
                             if literals.len() >= MAX_UNION_LITERALS {
-                                too_large = true;
-                                break;
+                                let replace_with = KnownClass::Bytes.to_instance(self.db);
+                                return self.add(replace_with);
                             }
                             literals.insert(literal);
                             found = true;
@@ -148,10 +142,6 @@ impl<'db> UnionBuilder<'db> {
                         _ => {}
                     }
                 }
-                if too_large {
-                    let replace_with = KnownClass::Bytes.to_instance(self.db);
-                    return self.add(replace_with);
-                }
                 if !found {
                     self.elements
                         .push(UnionElement::BytesLiterals(FxOrderSet::from_iter([
@@ -162,13 +152,12 @@ impl<'db> UnionBuilder<'db> {
             // And same for int literals as well.
             Type::IntLiteral(literal) => {
                 let mut found = false;
-                let mut too_large = false;
                 for element in &mut self.elements {
                     match element {
                         UnionElement::IntLiterals(literals) => {
                             if literals.len() >= MAX_UNION_LITERALS {
-                                too_large = true;
-                                break;
+                                let replace_with = KnownClass::Int.to_instance(self.db);
+                                return self.add(replace_with);
                             }
                             literals.insert(literal);
                             found = true;
@@ -180,10 +169,6 @@ impl<'db> UnionBuilder<'db> {
                         _ => {}
                     }
                 }
-                if too_large {
-                    let replace_with = KnownClass::Int.to_instance(self.db);
-                    return self.add(replace_with);
-                }
                 if !found {
                     self.elements
                         .push(UnionElement::IntLiterals(FxOrderSet::from_iter([literal])));