[checkpoint] Fix NumParams location for lambdas

Author: amomchilov

parser/prism/Translator.cc

@@ -4459,20 +4459,45 @@ ast::ExpressionPtr Translator::desugarHash(core::LocOffsets loc, NodeVec &kvPair
 // or `pm_lambda_node *`, and wrapping it around the given `Send` node.
 unique_ptr<parser::Node> Translator::translateCallWithBlock(pm_node_t *prismBlockOrLambdaNode,
                                                             unique_ptr<parser::Node> sendNode) {
-    unique_ptr<parser::Node> parametersNode;
+    pm_node_t *prismParametersNode;
     unique_ptr<parser::Node> body;
     auto blockLoc = translateLoc(prismBlockOrLambdaNode->location);
     if (PM_NODE_TYPE_P(prismBlockOrLambdaNode, PM_BLOCK_NODE)) {
         auto prismBlockNode = down_cast<pm_block_node>(prismBlockOrLambdaNode);
-        parametersNode = translate(prismBlockNode->parameters);
+        prismParametersNode = prismBlockNode->parameters;
         body = this->enterBlockContext().translate(prismBlockNode->body);
     } else {
         ENFORCE(PM_NODE_TYPE_P(prismBlockOrLambdaNode, PM_LAMBDA_NODE))
         auto prismLambdaNode = down_cast<pm_lambda_node>(prismBlockOrLambdaNode);
-        parametersNode = translate(prismLambdaNode->parameters);
+        prismParametersNode = prismLambdaNode->parameters; // need to change location here.
         body = this->enterBlockContext().translate(prismLambdaNode->body);
     }
 
+    unique_ptr<parser::Node> parametersNode;
+    if (prismParametersNode != nullptr) {
+        switch (PM_NODE_TYPE(prismParametersNode)) {
+            case PM_NUMBERED_PARAMETERS_NODE: {
+                if (PM_NODE_TYPE_P(prismBlockOrLambdaNode, PM_BLOCK_NODE)) {
+                    auto prismBlockNode = down_cast<pm_block_node>(prismBlockOrLambdaNode);
+                    parametersNode = translate(prismBlockNode->parameters);
+                } else {
+                    ENFORCE(PM_NODE_TYPE_P(prismBlockOrLambdaNode, PM_LAMBDA_NODE))
+                    auto prismLambdaNode = down_cast<pm_lambda_node>(prismBlockOrLambdaNode);
+                    prismLambdaNode->parameters->location = (pm_location_t){.start = prismLambdaNode->operator_loc.end,
+                                                                            .end = prismLambdaNode->operator_loc.end};
+                    parametersNode = translate(prismLambdaNode->parameters);
+                    body = this->enterBlockContext().translate(prismLambdaNode->body);
+                }
+
+                break;
+            }
+            default: {
+                parametersNode = translate(prismParametersNode);
+                break;
+            }
+        }
+    }
+
     // Modify send node's endLoc to be position before first space
     // This fixes location for cases like:
     //   Module.new do

test/prism_regression/lambda.rb

@@ -23,4 +23,6 @@ def method_returning_lambda
 end
 
 # Empty lambda parameters
-->() { 1 + 2 }
+->() { 1 }
+-> (){ 2 }
+-> () { 3 }