fix corner case in hoist_vars (#5627)

fixes #5626

lib/compress.js

@@ -8221,59 +8221,9 @@ Compressor.prototype.compress = function(node) {
                 vars.set(name, defn);
                 defn.name.definition().orig.unshift(defn.name);
             });
-            if (defns.length > 0) {
+            if (defns.length > 0) hoisted.push(make_node(AST_Var, self, { definitions: defns }));
-                // try to merge in assignments
-                insert_vars(self.body);
-                hoisted.push(make_node(AST_Var, self, { definitions: defns }));
-            }
         }
         self.body = dirs.concat(hoisted, self.body);
-
-        function insert_vars(body) {
-            while (body.length) {
-                var stat = body[0];
-                if (stat instanceof AST_SimpleStatement) {
-                    var expr = stat.body, sym, assign;
-                    if (expr instanceof AST_Assign
-                        && expr.operator == "="
-                        && (sym = expr.left) instanceof AST_Symbol
-                        && vars.has(sym.name)) {
-                        var defn = vars.get(sym.name);
-                        if (defn.value) break;
-                        var value = expr.right;
-                        if (value instanceof AST_Sequence) value = value.clone();
-                        defn.value = value;
-                        remove(defns, defn);
-                        defns.push(defn);
-                        body.shift();
-                        continue;
-                    }
-                    if (expr instanceof AST_Sequence
-                        && (assign = expr.expressions[0]) instanceof AST_Assign
-                        && assign.operator == "="
-                        && (sym = assign.left) instanceof AST_Symbol
-                        && vars.has(sym.name)) {
-                        var defn = vars.get(sym.name);
-                        if (defn.value) break;
-                        defn.value = assign.right;
-                        remove(defns, defn);
-                        defns.push(defn);
-                        stat.body = make_sequence(expr, expr.expressions.slice(1));
-                        continue;
-                    }
-                }
-                if (stat instanceof AST_EmptyStatement) {
-                    body.shift();
-                    continue;
-                }
-                if (stat instanceof AST_BlockStatement && !insert_vars(stat.body)) {
-                    body.shift();
-                    continue;
-                }
-                break;
-            }
-            return body.length;
-        }
     });
 
     function scan_local_returns(fn, transform) {

test/compress/default-values.js

@@ -668,6 +668,8 @@ drop_fargs: {
 hoist_vars: {
     options = {
         hoist_vars: true,
+        join_vars: true,
+        unused: true,
     }
     input: {
         var a = "PASS";
@@ -675,8 +677,7 @@ hoist_vars: {
         console.log(a, b);
     }
     expect: {
-        var a = "PASS";
+        var a = "PASS", [ b = 42 ] = [];
-        var [ b = 42 ] = [];
         console.log(a, b);
     }
     expect_stdout: "PASS 42"
@@ -3035,7 +3036,8 @@ issue_5566_5: {
         (function(a, f = function() {
             return a;
         }) {
-            var b, a = "foo";
+            var a, b;
+            a = "foo";
             console.log(a, f());
         })("bar");
     }

test/compress/destructured.js

@@ -1652,6 +1652,8 @@ fn_name_unused: {
 hoist_vars: {
     options = {
         hoist_vars: true,
+        join_vars: true,
+        unused: true,
     }
     input: {
         var a = "PASS";
@@ -1659,8 +1661,7 @@ hoist_vars: {
         console.log(a, b);
     }
     expect: {
-        var a = "PASS";
+        var a = "PASS", b = [ 42 ][0];
-        var [ b ] = [ 42 ];
         console.log(a, b);
     }
     expect_stdout: "PASS 42"

test/compress/hoist_vars.js

@@ -2,6 +2,8 @@ statements: {
     options = {
         hoist_funs: false,
         hoist_vars: true,
+        join_vars: true,
+        unused: true,
     }
     input: {
         function f() {
@@ -25,6 +27,8 @@ statements_funs: {
     options = {
         hoist_funs: true,
         hoist_vars: true,
+        join_vars: true,
+        unused: true,
     }
     input: {
         function f() {
@@ -48,6 +52,8 @@ sequences: {
     options = {
         hoist_funs: false,
         hoist_vars: true,
+        join_vars: true,
+        unused: true,
     }
     input: {
         function f() {
@@ -71,6 +77,8 @@ sequences_funs: {
     options = {
         hoist_funs: true,
         hoist_vars: true,
+        join_vars: true,
+        unused: true,
     }
     input: {
         function f() {
@@ -108,7 +116,8 @@ catch_var: {
         console.log(a);
     }
     expect: {
-        var a = "PASS";
+        a = "PASS";
+        var a;
         console.log(a);
     }
     expect_stdout: "PASS"
@@ -118,6 +127,8 @@ issue_2295: {
     options = {
         collapse_vars: true,
         hoist_vars: true,
+        join_vars: true,
+        unused: true,
     }
     input: {
         function foo(o) {
@@ -139,6 +150,7 @@ issue_4487_1: {
     options = {
         functions: true,
         hoist_vars: true,
+        join_vars: true,
         keep_fnames: true,
         reduce_vars: true,
         toplevel: true,
@@ -163,6 +175,7 @@ issue_4487_2: {
     options = {
         functions: true,
         hoist_vars: true,
+        join_vars: true,
         keep_fnames: true,
         passes: 2,
         reduce_vars: true,
@@ -188,6 +201,7 @@ issue_4487_3: {
     options = {
         functions: true,
         hoist_vars: true,
+        join_vars: true,
         keep_fnames: true,
         passes: 3,
         reduce_vars: true,
@@ -248,8 +262,7 @@ issue_4517: {
     }
     expect: {
         console.log(function() {
-            var a = 2;
+            return (A = 2) + typeof !1;
-            return (A = a) + typeof !1;
         }());
     }
     expect_stdout: "2boolean"
@@ -260,6 +273,7 @@ issue_4736: {
         collapse_vars: true,
         evaluate: true,
         hoist_vars: true,
+        join_vars: true,
         merge_vars: true,
         reduce_vars: true,
         toplevel: true,
@@ -279,7 +293,7 @@ issue_4736: {
     expect: {
         (function() {
             (function() {
-                0,
+                0;
                 console.log(1 << 30);
             })();
         })();
@@ -291,6 +305,7 @@ issue_4839: {
     options = {
         evaluate: true,
         hoist_vars: true,
+        join_vars: true,
         keep_fargs: false,
         reduce_vars: true,
         toplevel: true,
@@ -317,6 +332,7 @@ issue_4859: {
     options = {
         evaluate: true,
         hoist_vars: true,
+        join_vars: true,
         keep_infinity: true,
         merge_vars: true,
         reduce_vars: true,
@@ -441,7 +457,7 @@ issue_4898: {
     expect_stdout: "PASS"
 }
 
-issue_5187: {
+issue_5187_1: {
     options = {
         hoist_props: true,
         hoist_vars: true,
@@ -459,6 +475,37 @@ issue_5187: {
         }
         f();
     }
+    expect: {
+        (function() {
+            var a, b;
+            a = 42;
+            do {
+                b = { 0: a++ };
+            } while (console.log(b[b ^= 0]));
+        })();
+    }
+    expect_stdout: "42"
+}
+
+issue_5187_2: {
+    options = {
+        hoist_props: true,
+        hoist_vars: true,
+        join_vars: true,
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        function f() {
+            var a = 42;
+            do {
+                var b = { 0: a++ };
+            } while (console.log(b[b ^= 0]));
+        }
+        f();
+    }
     expect: {
         (function() {
             var b, a = 42;
@@ -547,9 +594,9 @@ issue_5411_1: {
         console.log(b);
     }
     expect: {
-        var b, c, a = "PASS";
+        var a, b, c;
         b++;
-        b = a;
+        b = a = "PASS";
         c = c && c[b];
         console.log(b);
     }
@@ -596,6 +643,30 @@ issue_5411_3: {
         var a = A = a;
         console.log(A);
     }
+    expect: {
+        var a;
+        a = console;
+        a = A = ++a;
+        console.log(A);
+    }
+    expect_stdout: "NaN"
+}
+
+issue_5411_4: {
+    options = {
+        collapse_vars: true,
+        hoist_vars: true,
+        join_vars: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = console;
+        a++;
+        var a = A = a;
+        console.log(A);
+    }
     expect: {
         var a = console;
         a = A = ++a;
@@ -603,3 +674,30 @@ issue_5411_3: {
     }
     expect_stdout: "NaN"
 }
+
+issue_5626: {
+    options = {
+        conditionals: true,
+        evaluate: true,
+        hoist_vars: true,
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = function() {
+            return console.log(arguments[0]), 42;
+        }("PASS") ? null : "foo";
+        for (var b in a)
+            FAIL;
+    }
+    expect: {
+        (function() {
+            console.log(arguments[0]);
+        }("PASS"));
+        for (var b in null)
+            FAIL;
+    }
+    expect_stdout: "PASS"
+}

test/compress/issue-913.js

@@ -1,17 +1,18 @@
 keep_var_for_in: {
     options = {
         hoist_vars: true,
+        join_vars: true,
         unused: true,
     }
     input: {
-        (function(obj){
+        (function(obj) {
             var foo = 5;
             for (var i in obj)
                 return foo;
         })();
     }
     expect: {
-        (function(obj){
+        (function(obj) {
             var i, foo = 5;
             for (i in obj)
                 return foo;

test/compress/pure_getters.js

@@ -1540,10 +1540,12 @@ this_toString: {
 issue_4803: {
     options = {
         hoist_vars: true,
+        join_vars: true,
         pure_getters: "strict",
         reduce_vars: true,
         side_effects: true,
         toplevel: true,
+        unused: true,
     }
     input: {
         var o = {