From 4fe630431c37ffb81466959e9ea9797d6d2de21a Mon Sep 17 00:00:00 2001
From: Richard van Velzen <rvanvelzen@experty.com>
Date: Sat, 23 Apr 2016 23:48:33 +0200
Subject: [PATCH 1/3] Hoist functions when reversing if (x) return; ... vs. if
 (!x) ...

Fixes #1052
---
 lib/compress.js             | 18 ++++++++++++++++--
 test/compress/issue-1052.js | 27 +++++++++++++++++++++++++++
 2 files changed, 43 insertions(+), 2 deletions(-)
 create mode 100644 test/compress/issue-1052.js

diff --git a/lib/compress.js b/lib/compress.js
index 53618ae1..2bcfcf30 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -578,11 +578,13 @@ merge(Compressor.prototype, {
                             CHANGED = true;
                             stat = stat.clone();
                             stat.condition = stat.condition.negate(compressor);
+                            var body = as_statement_array(stat.alternative).concat(ret);
+                            var funs = extract_functions_from_statement_array(body);
                             stat.body = make_node(AST_BlockStatement, stat, {
-                                body: as_statement_array(stat.alternative).concat(ret)
+                                body: body
                             });
                             stat.alternative = null;
-                            ret = [ stat.transform(compressor) ];
+                            ret = funs.concat([ stat.transform(compressor) ]);
                             continue loop;
                         }
                         //---
@@ -840,6 +842,18 @@ merge(Compressor.prototype, {
 
     };
 
+    function extract_functions_from_statement_array(statements) {
+        var funs = [];
+        for (var i = statements.length - 1; i >= 0; --i) {
+            var stat = statements[i];
+            if (stat instanceof AST_Defun) {
+                statements.splice(i, 1);
+                funs.unshift(stat);
+            }
+        }
+        return funs;
+    }
+
     function extract_declarations_from_unreachable_code(compressor, stat, target) {
         if (!(stat instanceof AST_Defun)) {
             compressor.warn("Dropping unreachable code [{file}:{line},{col}]", stat.start);
diff --git a/test/compress/issue-1052.js b/test/compress/issue-1052.js
new file mode 100644
index 00000000..067eea4a
--- /dev/null
+++ b/test/compress/issue-1052.js
@@ -0,0 +1,27 @@
+hoist_funs_when_handling_if_return_rerversal: {
+    options = { if_return: true, hoist_funs: false };
+    input: {
+        "use strict";
+
+        ( function() {
+            if ( !window ) {
+                return;
+            }
+
+            function f() {}
+            function g() {}
+        } )();
+    }
+    expect: {
+        "use strict";
+
+        ( function() {
+            function f() {}
+            function g() {}
+
+            // NOTE: other compression steps will reduce this
+            // down to just `window`.
+            if ( window );
+        } )();
+    }
+}

From 4d9a0856870fc8feb07771fe2e27d93c8613e857 Mon Sep 17 00:00:00 2001
From: Richard van Velzen <rvanvelzen@experty.com>
Date: Tue, 26 Apr 2016 11:43:03 +0200
Subject: [PATCH 2/3] Add test case for hoisting a single function

---
 test/compress/issue-1052.js | 26 +++++++++++++++++++++-----
 1 file changed, 21 insertions(+), 5 deletions(-)

diff --git a/test/compress/issue-1052.js b/test/compress/issue-1052.js
index 067eea4a..bad28a8f 100644
--- a/test/compress/issue-1052.js
+++ b/test/compress/issue-1052.js
@@ -1,8 +1,6 @@
-hoist_funs_when_handling_if_return_rerversal: {
+multiple_functions: {
     options = { if_return: true, hoist_funs: false };
     input: {
-        "use strict";
-
         ( function() {
             if ( !window ) {
                 return;
@@ -13,8 +11,6 @@ hoist_funs_when_handling_if_return_rerversal: {
         } )();
     }
     expect: {
-        "use strict";
-
         ( function() {
             function f() {}
             function g() {}
@@ -25,3 +21,23 @@ hoist_funs_when_handling_if_return_rerversal: {
         } )();
     }
 }
+
+single_function: {
+    options = { if_return: true, hoist_funs: false };
+    input: {
+        ( function() {
+            if ( !window ) {
+                return;
+            }
+
+            function f() {}
+        } )();
+    }
+    expect: {
+        ( function() {
+            function f() {}
+
+            if ( window );
+        } )();
+    }
+}

From e9224ab4441ddb352566a52b84f1384bf5b8a8d8 Mon Sep 17 00:00:00 2001
From: Richard van Velzen <rvanvelzen@experty.com>
Date: Tue, 26 Apr 2016 11:49:55 +0200
Subject: [PATCH 3/3] Add test cases for slightly more esoteric cases

---
 test/compress/issue-1052.js | 53 +++++++++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)

diff --git a/test/compress/issue-1052.js b/test/compress/issue-1052.js
index bad28a8f..0a77f006 100644
--- a/test/compress/issue-1052.js
+++ b/test/compress/issue-1052.js
@@ -41,3 +41,56 @@ single_function: {
         } )();
     }
 }
+
+deeply_nested: {
+    options = { if_return: true, hoist_funs: false };
+    input: {
+        ( function() {
+            if ( !window ) {
+                return;
+            }
+
+            function f() {}
+            function g() {}
+
+            if ( !document ) {
+                return;
+            }
+
+            function h() {}
+        } )();
+    }
+    expect: {
+        ( function() {
+            function f() {}
+            function g() {}
+
+            function h() {}
+
+            // NOTE: other compression steps will reduce this
+            // down to just `window`.
+            if ( window )
+                if (document);
+        } )();
+    }
+}
+
+not_hoisted_when_already_nested: {
+    options = { if_return: true, hoist_funs: false };
+    input: {
+        ( function() {
+            if ( !window ) {
+                return;
+            }
+
+            if ( foo ) function f() {}
+
+        } )();
+    }
+    expect: {
+        ( function() {
+            if ( window )
+                if ( foo ) function f() {}
+        } )();
+    }
+}