fix corner case in conditionals (#5335)

fixes #5334

lib/compress.js

@@ -1552,6 +1552,12 @@ Compressor.prototype.compress = function(node) {
     AST_SymbolDeclaration.DEFMETHOD("convert_symbol", convert_symbol);
     AST_SymbolRef.DEFMETHOD("convert_symbol", convert_symbol);
 
+    function process_to_assign(ref) {
+        var def = ref.definition();
+        def.assignments++;
+        def.references.push(ref);
+    }
+
     function mark_destructured(process, tw) {
         var marker = new TreeWalker(function(node) {
             if (node instanceof AST_DefaultValue) {
@@ -3539,9 +3545,7 @@ Compressor.prototype.compress = function(node) {
                         if (!var_def.value) return;
                         exprs.push(make_node(AST_Assign, var_def, {
                             operator: "=",
-                            left: var_def.name.convert_symbol(AST_SymbolRef, function(ref) {
+                            left: var_def.name.convert_symbol(AST_SymbolRef, process_to_assign),
-                                ref.definition().references.push(ref);
-                            }),
                             right: var_def.value,
                         }));
                     });
@@ -9084,9 +9088,7 @@ Compressor.prototype.compress = function(node) {
                         body: make_sequence(self.body, body_exprs),
                     });
                 }
-                body_refs.forEach(function(ref) {
+                body_refs.forEach(process_to_assign);
-                    ref.definition().references.push(ref);
-                });
             }
             if (alt_exprs) {
                 [].push.apply(body, alt_defuns);
@@ -9100,9 +9102,7 @@ Compressor.prototype.compress = function(node) {
                         body: make_sequence(self.alternative, alt_exprs),
                     });
                 }
-                alt_refs.forEach(function(ref) {
+                alt_refs.forEach(process_to_assign);
-                    ref.definition().references.push(ref);
-                });
             }
             if (var_defs.length > 0) body.push(make_node(AST_Var, self, { definitions: var_defs }));
             if (body.length > 0) {
@@ -9146,12 +9146,8 @@ Compressor.prototype.compress = function(node) {
                     }),
                 }).optimize(compressor));
             }
-            body_refs.forEach(function(ref) {
+            body_refs.forEach(process_to_assign);
-                ref.definition().references.push(ref);
+            alt_refs.forEach(process_to_assign);
-            });
-            alt_refs.forEach(function(ref) {
-                ref.definition().references.push(ref);
-            });
             return make_node(AST_BlockStatement, self, { body: body }).optimize(compressor);
         }
         if (is_empty(self.body)) self = make_node(AST_If, self, {
@@ -10450,6 +10446,7 @@ Compressor.prototype.compress = function(node) {
             scope.enclosed.push(def);
             if (!value) return;
             var sym = make_node(AST_SymbolRef, name, name);
+            def.assignments++;
             def.references.push(sym);
             expressions.push(make_node(AST_Assign, self, {
                 operator: "=",
@@ -10523,6 +10520,7 @@ Compressor.prototype.compress = function(node) {
 
             function process(ref, name) {
                 var def = name.definition();
+                def.assignments++;
                 def.references.push(ref);
                 var symbol = make_node(AST_SymbolVar, name, name);
                 def.orig.push(symbol);

test/compress/conditionals.js

@@ -2007,3 +2007,58 @@ issue_5232_3: {
         "undefined",
     ]
 }
+
+issue_5334_1: {
+    options = {
+        conditionals: true,
+        hoist_props: true,
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        function f() {
+            if (console.log("PASS"))
+                var o = true, o = {
+                    p: o += console.log("FAIL"),
+                };
+        }
+        f();
+    }
+    expect: {
+        (function() {
+            var o;
+            console.log("PASS") && (o = true, o = {
+                p: o += console.log("FAIL"),
+            });
+        })();
+    }
+    expect_stdout: "PASS"
+}
+
+issue_5334_2: {
+    options = {
+        conditionals: true,
+        hoist_props: true,
+        inline: true,
+        passes: 3,
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        function f() {
+            if (console.log("PASS"))
+                var o = true, o = {
+                    p: o += console.log("FAIL"),
+                };
+        }
+        f();
+    }
+    expect: {
+        console.log("PASS") && console.log("FAIL");
+    }
+    expect_stdout: "PASS"
+}