Combine if and unless guard conditions

Shopify · Oct 24, 2024 · af24f04 · af24f04
1 parent fb82456
commit af24f04
Showing 1 changed file with 22 additions and 25 deletions.
diff --git a/parser/prism/Translator.cc b/parser/prism/Translator.cc
@@ -1343,39 +1343,36 @@ unique_ptr<parser::Node> Translator::patternTranslate(pm_node_t *node) {
         case PM_IN_NODE: { // An `in` pattern such as in a `case` statement, or as a standalone expression.
             auto inNode = down_cast<pm_in_node>(node);
 
-            auto prismPattern = move(inNode->pattern);
+            auto prismPattern = inNode->pattern;
+            unique_ptr<parser::Node> sorbetPattern;
+            unique_ptr<parser::Node> sorbetGuard;
             auto inlineIfSingle = true;
             auto statements = translateStatements(inNode->statements, inlineIfSingle);
 
-            if (prismPattern != nullptr && PM_NODE_TYPE_P(prismPattern, PM_IF_NODE)) {
-                auto ifNode = reinterpret_cast<pm_if_node *>(prismPattern);
-                auto prismStatements = reinterpret_cast<pm_statements_node *>(ifNode->statements);
-
-                if (prismStatements->body.size != 1) {
-                    unreachable("In pattern-matching's `in` clause, an `if` guard must have a single statement.");
+            if (prismPattern != nullptr &&
+                (PM_NODE_TYPE_P(prismPattern, PM_IF_NODE) || PM_NODE_TYPE_P(prismPattern, PM_UNLESS_NODE))) {
+                pm_statements_node *conditionalStatements = nullptr;
+
+                if (PM_NODE_TYPE_P(prismPattern, PM_IF_NODE)) {
+                    auto ifNode = down_cast<pm_if_node>(prismPattern);
+                    conditionalStatements = ifNode->statements;
+                    sorbetGuard = make_unique<parser::IfGuard>(location, translate(ifNode->predicate));
+                } else { // PM_UNLESS_NODE
+                    auto unlessNode = down_cast<pm_unless_node>(prismPattern);
+                    conditionalStatements = unlessNode->statements;
+                    sorbetGuard = make_unique<parser::UnlessGuard>(location, translate(unlessNode->predicate));
                 }
 
-                auto sorbetPattern = patternTranslate(prismStatements->body.nodes[0]);
-                auto sorbetGuard = make_unique<parser::IfGuard>(location, translate(ifNode->predicate));
-
-                return make_unique<parser::InPattern>(location, move(sorbetPattern), move(sorbetGuard), move(statements));
-            } else if (prismPattern != nullptr && PM_NODE_TYPE_P(prismPattern, PM_UNLESS_NODE)) {
-                auto unlessNode = reinterpret_cast<pm_unless_node *>(prismPattern);
-                auto prismStatements = reinterpret_cast<pm_statements_node *>(unlessNode->statements);
-
-                if (prismStatements->body.size != 1) {
-                    unreachable("In pattern-matching's `in` clause, an `unless` guard must have a single statement.");
-                }
+                ENFORCE(
+                    conditionalStatements->body.size == 1,
+                    "In pattern-matching's `in` clause, a conditional (if/unless) guard must have a single statement.");
 
-                auto sorbetPattern = patternTranslate(prismStatements->body.nodes[0]);
-                auto sorbetGuard = make_unique<parser::UnlessGuard>(location, translate(unlessNode->predicate));
-
-                return make_unique<parser::InPattern>(location, move(sorbetPattern), move(sorbetGuard), move(statements));
+                sorbetPattern = patternTranslate(conditionalStatements->body.nodes[0]);
             } else {
-                auto sorbetPattern = patternTranslate(prismPattern);
-
-                return make_unique<parser::InPattern>(location, move(sorbetPattern), nullptr, move(statements));
+                sorbetPattern = patternTranslate(prismPattern);
             }
+
+            return make_unique<parser::InPattern>(location, move(sorbetPattern), move(sorbetGuard), move(statements));
         }
         case PM_LOCAL_VARIABLE_TARGET_NODE: { // A variable binding in a pattern, like the `head` in `[head, *tail]`
             auto localVarTargetNode = down_cast<pm_local_variable_target_node>(node);