From 9a6faf365bdd481be733bafb8c580bc76f4b353e Mon Sep 17 00:00:00 2001
From: "Alex Lam S.L" <alexlamsl@gmail.com>
Date: Mon, 2 Dec 2019 06:43:54 +0800
Subject: [PATCH] fix corner cases in `keep_fargs` & `unused` (#3618)

---
 lib/compress.js                |  16 +-
 test/compress/collapse_vars.js |  43 +++---
 test/compress/drop-unused.js   |  12 +-
 test/compress/evaluate.js      |   4 +-
 test/compress/functions.js     |   2 +-
 test/compress/keep_fargs.js    | 270 +++++++++++++++++++++++++++++++++
 test/compress/reduce_vars.js   |  12 +-
 7 files changed, 320 insertions(+), 39 deletions(-)

diff --git a/lib/compress.js b/lib/compress.js
index 09019a7419..284b79adfc 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -5173,12 +5173,14 @@ merge(Compressor.prototype, {
             && !fn.uses_arguments
             && !fn.pinned()) {
             var pos = 0, last = 0;
+            var drop_fargs = exp === fn && compressor.drop_fargs(fn, self)
+                && (!fn.name || !fn.name.definition().recursive_refs);
             var side_effects = [];
             for (var i = 0; i < self.args.length; i++) {
                 var trim = i >= fn.argnames.length;
                 if (trim || fn.argnames[i].__unused) {
                     var node = self.args[i].drop_side_effect_free(compressor);
-                    if (exp === fn) {
+                    if (drop_fargs) {
                         fn.argnames.splice(i, 1);
                         self.args.splice(i, 1);
                         if (node) side_effects.push(node);
@@ -5207,8 +5209,17 @@ merge(Compressor.prototype, {
                 }
                 last = pos;
             }
+            if (drop_fargs) for (; i < fn.argnames.length; i++) {
+                if (fn.argnames[i].__unused) fn.argnames.splice(i--, 1);
+            }
             self.args.length = last;
-            if (side_effects.length) self.args.push(make_sequence(self, side_effects));
+            if (side_effects.length) {
+                var arg = make_sequence(self, side_effects);
+                self.args.push(self.args.length < fn.argnames.length ? make_node(AST_UnaryPrefix, self, {
+                    operator: "void",
+                    expression: arg
+                }) : arg);
+            }
         }
         if (compressor.option("unsafe")) {
             if (is_undeclared_ref(exp)) switch (exp.name) {
@@ -6568,6 +6579,7 @@ merge(Compressor.prototype, {
                         name.scope = value;
                         value.name = name;
                         lambda_def = value.def_function(name);
+                        lambda_def.recursive_refs = def.recursive_refs;
                     }
                     value.walk(new TreeWalker(function(node) {
                         if (!(node instanceof AST_SymbolRef)) return;
diff --git a/test/compress/collapse_vars.js b/test/compress/collapse_vars.js
index eef6377991..58325be1db 100644
--- a/test/compress/collapse_vars.js
+++ b/test/compress/collapse_vars.js
@@ -1051,7 +1051,6 @@ collapse_vars_repeated: {
              var a = "GOOD" + x, e = "BAD", k = "!", e = a;
              console.log(e + k);
         })("!"),
-
         (function(x) {
             var a = "GOOD" + x, e = "BAD" + x, k = "!", e = a;
             console.log(e + k);
@@ -1064,10 +1063,10 @@ collapse_vars_repeated: {
         function f2(x) {
             return x;
         }
-        (function() {
+        (function(x) {
              console.log("GOOD!!");
         })(),
-        (function() {
+        (function(x) {
              console.log("GOOD!!");
         })();
     }
@@ -2425,7 +2424,7 @@ issue_1858: {
         }(1));
     }
     expect: {
-        console.log(function() {
+        console.log(function(x) {
             var a = {}, b = a.b = 1;
             return a.b + b;
         }());
@@ -2569,12 +2568,12 @@ chained_3: {
         }(1, 2));
     }
     expect: {
-        console.log(function(b) {
+        console.log(function(a, b) {
             var c = 1;
             c = b;
             b++;
             return c;
-        }(2));
+        }(0, 2));
     }
     expect_stdout: "2"
 }
@@ -2845,7 +2844,7 @@ issue_2187_2: {
     }
     expect: {
         var b = 1;
-        console.log(function() {
+        console.log(function(a) {
             return b-- && ++b;
         }());
     }
@@ -2924,7 +2923,7 @@ issue_2203_2: {
         console.log({
             a: "FAIL",
             b: function() {
-                return function() {
+                return function(c) {
                     return (String, (Object, function() {
                         return this;
                     }())).a;
@@ -3081,7 +3080,7 @@ issue_2319_1: {
         }()));
     }
     expect: {
-        console.log(function() {
+        console.log(function(a) {
             return !function() {
                 return this;
             }();
@@ -3129,7 +3128,7 @@ issue_2319_3: {
     }
     expect: {
         "use strict";
-        console.log(function() {
+        console.log(function(a) {
             return !function() {
                 return this;
             }();
@@ -3594,7 +3593,7 @@ issue_2425_2: {
     }
     expect: {
         var a = 8;
-        (function(b) {
+        (function(b, c) {
             b.toString();
         })(--a, a |= 10);
         console.log(a);
@@ -3616,7 +3615,7 @@ issue_2425_3: {
     }
     expect: {
         var a = 8;
-        (function() {
+        (function(b, b) {
             (a |= 10).toString();
         })(--a);
         console.log(a);
@@ -4160,7 +4159,7 @@ issue_2436_13: {
         var a = "PASS";
         (function() {
             (function(b) {
-                (function() {
+                (function(b) {
                     a && (a.null = "FAIL");
                 })();
             })();
@@ -4264,11 +4263,11 @@ issue_2506: {
     expect: {
         var c = 0;
         function f0(bar) {
-            (function() {
-                (function() {
+            (function(Infinity_2) {
+                (function(NaN) {
                     if (false <= 0/0 & this >> 1 >= 0)
                         c++;
-                })(c++);
+                })(0, c++);
             })();
         }
         f0(false);
@@ -4566,20 +4565,20 @@ replace_all_var_scope: {
         var a = 100, b = 10;
         (function(r, a) {
             switch (~a) {
-            case (b += a):
-            case a++:
+              case (b += a):
+              case a++:
             }
         })(--b, a);
         console.log(a, b);
     }
     expect: {
         var a = 100, b = 10;
-        (function(c) {
+        (function(c, o) {
             switch (~a) {
-            case (b += a):
-            case c++:
+              case (b += a):
+              case o++:
             }
-        })((--b, a));
+        })(--b, a);
         console.log(a, b);
     }
     expect_stdout: "100 109"
diff --git a/test/compress/drop-unused.js b/test/compress/drop-unused.js
index bc18db9add..15420d8ab6 100644
--- a/test/compress/drop-unused.js
+++ b/test/compress/drop-unused.js
@@ -815,9 +815,9 @@ issue_1583: {
     }
     expect: {
         function m(t) {
-            (function() {
+            (function(e) {
                 (function() {
-                    return (function() {
+                    return (function(a) {
                         return function(a) {};
                     })();
                 })();
@@ -1329,7 +1329,7 @@ issue_2226_2: {
         }(1, 2));
     }
     expect: {
-        console.log(function(a) {
+        console.log(function(a, b) {
             return a += 2;
         }(1));
     }
@@ -1349,7 +1349,7 @@ issue_2226_3: {
         }(1, 2));
     }
     expect: {
-        console.log(function(a) {
+        console.log(function(a, b) {
             return a += 2;
         }(1));
     }
@@ -1702,11 +1702,11 @@ chained_3: {
         }(1, 2));
     }
     expect: {
-        console.log(function(b) {
+        console.log(function(a, b) {
             var c = b;
             b++;
             return c;
-        }(2));
+        }(0, 2));
     }
     expect_stdout: "2"
 }
diff --git a/test/compress/evaluate.js b/test/compress/evaluate.js
index fadf717e04..09fdfb2ad3 100644
--- a/test/compress/evaluate.js
+++ b/test/compress/evaluate.js
@@ -1674,7 +1674,7 @@ if_increment: {
         }(0));
     }
     expect: {
-        console.log(function() {
+        console.log(function(a) {
             if (console)
                 return 1;
         }());
@@ -1696,7 +1696,7 @@ try_increment: {
         }(0));
     }
     expect: {
-        console.log(function() {
+        console.log(function(a) {
             try {
                 return 1;
             } catch (e) {}
diff --git a/test/compress/functions.js b/test/compress/functions.js
index 1473f74c45..4fea42dc45 100644
--- a/test/compress/functions.js
+++ b/test/compress/functions.js
@@ -1279,7 +1279,7 @@ issue_2630_3: {
     expect: {
         var x = 2, a = 1;
         (function() {
-            (function f1() {
+            (function f1(a) {
                 f2();
                 --x >= 0 && f1({});
             })(a++);
diff --git a/test/compress/keep_fargs.js b/test/compress/keep_fargs.js
index 440abbd919..29308ff3b6 100644
--- a/test/compress/keep_fargs.js
+++ b/test/compress/keep_fargs.js
@@ -1155,3 +1155,273 @@ issue_3423_2: {
     }
     expect_stdout: "1"
 }
+
+collapse_vars_repeated: {
+    options = {
+        booleans: true,
+        collapse_vars: true,
+        comparisons: true,
+        conditionals: true,
+        dead_code: true,
+        evaluate: true,
+        hoist_funs: true,
+        if_return: true,
+        join_vars: true,
+        keep_fargs: "strict",
+        loops: true,
+        properties: true,
+        reduce_funcs: true,
+        reduce_vars: true,
+        sequences: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        function f1() {
+            var dummy = 3, a = 5, unused = 2, a = 1, a = 3;
+            return -a;
+        }
+        function f2(x) {
+            var a = 3, a = x;
+            return a;
+        }
+        (function(x) {
+             var a = "GOOD" + x, e = "BAD", k = "!", e = a;
+             console.log(e + k);
+        })("!"),
+        (function(x) {
+            var a = "GOOD" + x, e = "BAD" + x, k = "!", e = a;
+            console.log(e + k);
+        })("!");
+    }
+    expect: {
+        function f1() {
+            return -3;
+        }
+        function f2(x) {
+            return x;
+        }
+        (function() {
+             console.log("GOOD!!");
+        })(),
+        (function() {
+             console.log("GOOD!!");
+        })();
+    }
+    expect_stdout: true
+}
+
+chained_3: {
+    options = {
+        collapse_vars: true,
+        keep_fargs: "strict",
+        unused: true,
+    }
+    input: {
+        console.log(function(a, b) {
+            var c = a, c = b;
+            b++;
+            return c;
+        }(1, 2));
+    }
+    expect: {
+        console.log(function(b) {
+            var c = 1;
+            c = b;
+            b++;
+            return c;
+        }(2));
+    }
+    expect_stdout: "2"
+}
+
+replace_all_var_scope: {
+    rename = true
+    options = {
+        collapse_vars: true,
+        keep_fargs: "strict",
+        unused: true,
+    }
+    mangle = {}
+    input: {
+        var a = 100, b = 10;
+        (function(r, a) {
+            switch (~a) {
+            case (b += a):
+            case a++:
+            }
+        })(--b, a);
+        console.log(a, b);
+    }
+    expect: {
+        var a = 100, b = 10;
+        (function(c) {
+            switch (~a) {
+            case (b += a):
+            case c++:
+            }
+        })((--b, a));
+        console.log(a, b);
+    }
+    expect_stdout: "100 109"
+}
+
+issue_1583: {
+    options = {
+        keep_fargs: "strict",
+        passes: 2,
+        reduce_funcs: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        function m(t) {
+            (function(e) {
+                t = e();
+            })(function() {
+                return (function(a) {
+                    return a;
+                })(function(a) {});
+            });
+        }
+    }
+    expect: {
+        function m(t) {
+            (function() {
+                (function() {
+                    return (function() {
+                        return function(a) {};
+                    })();
+                })();
+            })();
+        }
+    }
+}
+
+issues_3267_1: {
+    options = {
+        collapse_vars: true,
+        conditionals: true,
+        dead_code: true,
+        evaluate: true,
+        inline: true,
+        keep_fargs: "strict",
+        reduce_vars: true,
+        sequences: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        (function(x) {
+            x();
+        })(function() {
+            (function(i) {
+                if (i)
+                    return console.log("PASS");
+                throw "FAIL";
+            })(Object());
+        });
+    }
+    expect: {
+        !function() {
+            if (Object())
+                return console.log("PASS");
+            throw "FAIL";
+        }();
+    }
+    expect_stdout: "PASS"
+}
+
+trailing_argument_side_effects: {
+    options = {
+        keep_fargs: "strict",
+        unused: true,
+    }
+    input: {
+        function f() {
+            return "FAIL";
+        }
+        console.log(function(a, b) {
+            return b || "PASS";
+        }(f()));
+    }
+    expect: {
+        function f() {
+            return "FAIL";
+        }
+        console.log(function(b) {
+            return b || "PASS";
+        }(void f()));
+    }
+    expect_stdout: "PASS"
+}
+
+recursive_iife_1: {
+    options = {
+        keep_fargs: "strict",
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        console.log(function f(a, b) {
+            return b || f("FAIL", "PASS");
+        }());
+    }
+    expect: {
+        console.log(function f(a, b) {
+            return b || f("FAIL", "PASS");
+        }());
+    }
+    expect_stdout: "PASS"
+}
+
+recursive_iife_2: {
+    options = {
+        keep_fargs: "strict",
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        console.log(function f(a, b) {
+            return b || f("FAIL", "PASS");
+        }(null, 0));
+    }
+    expect: {
+        console.log(function f(a, b) {
+            return b || f("FAIL", "PASS");
+        }(0, 0));
+    }
+    expect_stdout: "PASS"
+}
+
+recursive_iife_3: {
+    options = {
+        keep_fargs: false,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        var a = 1, c = "PASS";
+        (function() {
+            function f(b, d, e) {
+                a-- && f(null, 42, 0);
+                e && (c = "FAIL");
+                d && d.p;
+            }
+            var a_1 = f();
+        })();
+        console.log(c);
+    }
+    expect: {
+        var a = 1, c = "PASS";
+        (function() {
+            (function f(b, d, e) {
+                a-- && f(null, 42, 0);
+                e && (c = "FAIL");
+                d && d.p;
+            })();
+        })();
+        console.log(c);
+    }
+    expect_stdout: "PASS"
+}
diff --git a/test/compress/reduce_vars.js b/test/compress/reduce_vars.js
index 9dcf96aaf5..a3421c001e 100644
--- a/test/compress/reduce_vars.js
+++ b/test/compress/reduce_vars.js
@@ -1599,7 +1599,7 @@ defun_label: {
     }
     expect: {
         !function() {
-            console.log(function() {
+            console.log(function(a) {
                 L: {
                     if (2) break L;
                     return 1;
@@ -1763,13 +1763,13 @@ iife_func_side_effects: {
         function z() {
             console.log("z");
         }
-        (function(b) {
+        (function(a, b, c) {
             return function() {
                 console.log("FAIL");
             } + b();
-        })((x(), function() {
+        })(x(), function() {
             return y();
-        }), z());
+        }, z());
     }
     expect_stdout: [
         "x",
@@ -1830,7 +1830,7 @@ issue_1595_3: {
         })(2);
     }
     expect: {
-        (function() {
+        (function(a) {
             return g(3);
         })();
     }
@@ -6602,7 +6602,7 @@ issues_3267_1: {
         });
     }
     expect: {
-        !function() {
+        !function(i) {
             if (Object())
                 return console.log("PASS");
             throw "FAIL";