From 57ed7e3d448befa2221d820370182cc3af7c1355 Mon Sep 17 00:00:00 2001
From: Lukas Taegert-Atkinson <lukastaegert@users.noreply.github.com>
Date: Sun, 16 Aug 2020 07:29:47 +0200
Subject: [PATCH] Prevent unintended ASI for nested conditionals (#3732)

---
 src/ast/nodes/ConditionalExpression.ts           |  1 +
 src/ast/nodes/LogicalExpression.ts               |  1 +
 src/ast/nodes/YieldExpression.ts                 |  2 +-
 .../samples/prevent-tree-shaking-asi/main.js     | 16 +++++++++++++---
 4 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/src/ast/nodes/ConditionalExpression.ts b/src/ast/nodes/ConditionalExpression.ts
index d1df1f77f25..1a498e4dbe6 100644
--- a/src/ast/nodes/ConditionalExpression.ts
+++ b/src/ast/nodes/ConditionalExpression.ts
@@ -187,6 +187,7 @@ export default class ConditionalExpression extends NodeBase implements Deoptimiz
 				isCalleeOfRenderedParent: renderedParentType
 					? isCalleeOfRenderedParent
 					: (this.parent as CallExpression).callee === this,
+				preventASI: true,
 				renderedParentType: renderedParentType || this.parent.type
 			});
 		} else {
diff --git a/src/ast/nodes/LogicalExpression.ts b/src/ast/nodes/LogicalExpression.ts
index 0d3976a0928..d6c37ddc08b 100644
--- a/src/ast/nodes/LogicalExpression.ts
+++ b/src/ast/nodes/LogicalExpression.ts
@@ -180,6 +180,7 @@ export default class LogicalExpression extends NodeBase implements Deoptimizable
 				isCalleeOfRenderedParent: renderedParentType
 					? isCalleeOfRenderedParent
 					: (this.parent as CallExpression).callee === this,
+				preventASI,
 				renderedParentType: renderedParentType || this.parent.type
 			});
 		} else {
diff --git a/src/ast/nodes/YieldExpression.ts b/src/ast/nodes/YieldExpression.ts
index ff0a96c3a6d..d322951c8fd 100644
--- a/src/ast/nodes/YieldExpression.ts
+++ b/src/ast/nodes/YieldExpression.ts
@@ -26,7 +26,7 @@ export default class YieldExpression extends NodeBase {
 
 	render(code: MagicString, options: RenderOptions) {
 		if (this.argument) {
-			this.argument.render(code, options);
+			this.argument.render(code, options, { preventASI: true });
 			if (this.argument.start === this.start + 5 /* 'yield'.length */) {
 				code.prependLeft(this.start + 5, ' ');
 			}
diff --git a/test/function/samples/prevent-tree-shaking-asi/main.js b/test/function/samples/prevent-tree-shaking-asi/main.js
index 8b91e02a84c..51deb9f78b9 100644
--- a/test/function/samples/prevent-tree-shaking-asi/main.js
+++ b/test/function/samples/prevent-tree-shaking-asi/main.js
@@ -2,7 +2,9 @@ function test1() {
 	return true ?
 		/* kept */
 
-		'expected' :
+		true ?
+			'expected' :
+			'unexpected' :
 		'unexpected';
 }
 assert.strictEqual(test1(), 'expected');
@@ -12,7 +14,9 @@ function test2() {
 		'unexpected' :
 		/* kept */
 
-		'expected';
+		false ?
+			'unexpected' :
+			'expected';
 }
 assert.strictEqual(test2(), 'expected');
 
@@ -20,7 +24,7 @@ function test3() {
 	return true &&
 		/* kept */
 
-		'expected';
+		'expected'  || false;
 }
 assert.strictEqual(test3(), 'expected');
 
@@ -40,3 +44,9 @@ try {
 } catch (err) {
 	assert.strictEqual(err.message, 'expected');
 }
+
+function* test5() {
+	yield false ||
+	'expected'
+}
+assert.strictEqual(test5().next().value, 'expected');