Handle debugger statements as if-statement branches

CHANGELOG.md

@@ -1,5 +1,14 @@
 # rollup changelog
 
+## 2.26.11
+*2020-09-08*
+
+### Bug Fixes
+* Do not fail for unknown nodes as if statement branches (#3769)
+
+### Pull Requests
+* [#3769](https://github.com/rollup/rollup/pull/3769): Handle debugger statements as if-statement branches (@lukastaegert)
+
 ## 2.26.10
 *2020-09-04*
 

src/ast/nodes/IfStatement.ts

@@ -70,18 +70,12 @@ export default class IfStatement extends StatementBase implements DeoptimizableE
 
 	parseNode(esTreeNode: GenericEsTreeNode) {
 		this.consequentScope = new TrackingScope(this.scope);
-		this.consequent = new this.context.nodeConstructors[esTreeNode.consequent.type](
-			esTreeNode.consequent,
-			this,
-			this.consequentScope
-		);
+		this.consequent = new (this.context.nodeConstructors[esTreeNode.consequent.type] ||
+			this.context.nodeConstructors.UnknownNode)(esTreeNode.consequent, this, this.consequentScope);
 		if (esTreeNode.alternate) {
 			this.alternateScope = new TrackingScope(this.scope);
-			this.alternate = new this.context.nodeConstructors[esTreeNode.alternate.type](
-				esTreeNode.alternate,
-				this,
-				this.alternateScope
-			);
+			this.alternate = new (this.context.nodeConstructors[esTreeNode.alternate.type] ||
+				this.context.nodeConstructors.UnknownNode)(esTreeNode.alternate, this, this.alternateScope);
 		}
 		super.parseNode(esTreeNode);
 	}

test/function/samples/unknown-statement/_config.js

@@ -0,0 +1,3 @@
+module.exports = {
+	description: 'handles unknown statements'
+};

test/function/samples/unknown-statement/main.js

@@ -0,0 +1,4 @@
+debugger;
+
+if (true) debugger;
+else debugger;