From 507557c48e598a1a53560a4706861e2c73f27dc7 Mon Sep 17 00:00:00 2001
From: Amjad Masad <amjad.masad@gmail.com>
Date: Tue, 17 Nov 2015 18:45:35 -0800
Subject: [PATCH 1/3] Add failing test

---
 .../plugins/nested-if-alternate/exec.js        | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)
 create mode 100644 packages/babel-core/test/fixtures/plugins/nested-if-alternate/exec.js

diff --git a/packages/babel-core/test/fixtures/plugins/nested-if-alternate/exec.js b/packages/babel-core/test/fixtures/plugins/nested-if-alternate/exec.js
new file mode 100644
index 0000000000..8c38fbbb5b
--- /dev/null
+++ b/packages/babel-core/test/fixtures/plugins/nested-if-alternate/exec.js
@@ -0,0 +1,18 @@
+var res = transform('', {
+  plugins: function (b) {
+    var t = b.types;
+    return {
+      visitor: {
+        Program: function(path) {
+          if (this.done) return;
+          var inner = t.ifStatement(t.booleanLiteral(true), t.expressionStatement(t.numericLiteral(42)), null);
+          var outer = t.ifStatement(t.booleanLiteral(false), inner, t.expressionStatement(t.numericLiteral(23)));
+          path.replaceWith(t.program([outer]));
+          this.done = true;
+        }
+      }
+    }
+  }
+});
+
+assert.equal(eval(res.code), 23);

From 35e575cf932e9ef4ea80328d82668c6c4f7ce782 Mon Sep 17 00:00:00 2001
From: Amjad Masad <amjad.masad@gmail.com>
Date: Tue, 17 Nov 2015 19:07:20 -0800
Subject: [PATCH 2/3] Print a block when encountering consequents that are if
 statements

---
 .../fixtures/plugins/nested-if-alternate/exec.js    |  1 +
 .../babel-generator/src/generators/statements.js    | 13 +++++++++++++
 2 files changed, 14 insertions(+)

diff --git a/packages/babel-core/test/fixtures/plugins/nested-if-alternate/exec.js b/packages/babel-core/test/fixtures/plugins/nested-if-alternate/exec.js
index 8c38fbbb5b..c9dae86ffa 100644
--- a/packages/babel-core/test/fixtures/plugins/nested-if-alternate/exec.js
+++ b/packages/babel-core/test/fixtures/plugins/nested-if-alternate/exec.js
@@ -5,6 +5,7 @@ var res = transform('', {
       visitor: {
         Program: function(path) {
           if (this.done) return;
+          // if (false) { if (true) 42; } else 23;
           var inner = t.ifStatement(t.booleanLiteral(true), t.expressionStatement(t.numericLiteral(42)), null);
           var outer = t.ifStatement(t.booleanLiteral(false), inner, t.expressionStatement(t.numericLiteral(23)));
           path.replaceWith(t.program([outer]));
diff --git a/packages/babel-generator/src/generators/statements.js b/packages/babel-generator/src/generators/statements.js
index 744ff256d5..f42ee49fcd 100644
--- a/packages/babel-generator/src/generators/statements.js
+++ b/packages/babel-generator/src/generators/statements.js
@@ -16,8 +16,21 @@ export function IfStatement(node: Object) {
   this.push(")");
   this.space();
 
+  let consequentIsIf = t.isIfStatement(node.consequent);
+  if (consequentIsIf) {
+    this.push("{");
+    this.newline();
+    this.indent();
+  }
+
   this.printAndIndentOnComments(node.consequent, node);
 
+  if (consequentIsIf) {
+    this.dedent();
+    this.newline();
+    this.push("}");
+  }
+
   if (node.alternate) {
     if (this.isLast("}")) this.space();
     this.push("else ");

From 1612c70c106689bd933d07bf192f045cb597058c Mon Sep 17 00:00:00 2001
From: Amjad Masad <amjad.masad@gmail.com>
Date: Tue, 17 Nov 2015 19:16:19 -0800
Subject: [PATCH 3/3] Take the alternate existence into account

---
 packages/babel-generator/src/generators/statements.js | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/packages/babel-generator/src/generators/statements.js b/packages/babel-generator/src/generators/statements.js
index f42ee49fcd..4e1e62393a 100644
--- a/packages/babel-generator/src/generators/statements.js
+++ b/packages/babel-generator/src/generators/statements.js
@@ -16,8 +16,8 @@ export function IfStatement(node: Object) {
   this.push(")");
   this.space();
 
-  let consequentIsIf = t.isIfStatement(node.consequent);
-  if (consequentIsIf) {
+  let needsBlock = node.alternate && t.isIfStatement(node.consequent);
+  if (needsBlock) {
     this.push("{");
     this.newline();
     this.indent();
@@ -25,7 +25,7 @@ export function IfStatement(node: Object) {
 
   this.printAndIndentOnComments(node.consequent, node);
 
-  if (consequentIsIf) {
+  if (needsBlock) {
     this.dedent();
     this.newline();
     this.push("}");