simplify computed properties for methods, getters & setters (#2555)

fixes #2554

lib/compress.js

@@ -5341,7 +5341,31 @@ merge(Compressor.prototype, {
         return self;
     });
 
+    // ["p"]:1 ---> p:1
+    // [42]:1 ---> 42:1
+    function lift_key(self, compressor) {
+        if (!compressor.option("computed_props")) return self;
+        // save a comparison in the typical case
+        if (!(self.key instanceof AST_Constant)) return self;
+        // whitelist acceptable props as not all AST_Constants are true constants
+        if (self.key instanceof AST_String || self.key instanceof AST_Number) {
+            if (self.key.value == "constructor"
+                && compressor.parent() instanceof AST_Class) return self;
+            if (self instanceof AST_ObjectKeyVal) {
+                self.key = self.key.value;
+            } else {
+                self.key = make_node(AST_SymbolMethod, self.key, {
+                    name: self.key.value
+                });
+            }
+        }
+        return self;
+    }
+
+    OPT(AST_ObjectProperty, lift_key);
+
     OPT(AST_ConciseMethod, function(self, compressor){
+        lift_key(self, compressor);
         // p(){return x;} ---> p:()=>x
         if (compressor.option("arrows")
             && compressor.parent() instanceof AST_Object
@@ -5362,18 +5386,7 @@ merge(Compressor.prototype, {
     });
 
     OPT(AST_ObjectKeyVal, function(self, compressor){
-        // ["p"]:1 ---> p:1
+        lift_key(self, compressor);
-        // [42]:1 ---> 42:1
-        if (compressor.option("computed_props")
-            && self.key instanceof AST_Constant // save a comparison in the typical case
-            && (
-                // whitelist acceptable props as not all AST_Constants are true constants
-                self.key instanceof AST_String
-                || self.key instanceof AST_Number
-            )) {
-            self.key = self.key.value;
-            // fallthrough - `return self` not needed as transformed tree in good form
-        }
         // p:function(){} ---> p(){}
         // p:function*(){} ---> *p(){}
         // p:async function(){} ---> async p(){}

test/compress/object.js

@@ -812,3 +812,204 @@ prop_arrow_with_nested_this: {
     ]
     node_version: ">=4"
 }
+
+issue_2554_1: {
+    options = {
+        computed_props: true,
+        evaluate: true,
+    }
+    input: {
+        var obj = {
+            ["x" + ""]: 1,
+            ["method" + ""]() {
+                this.s = "PASS";
+            },
+            get ["g" + ""]() {
+                return this.x;
+            },
+            set ["s" + ""](value) {
+                this.x = value;
+            }
+        };
+        obj.method();
+        console.log(obj.g);
+    }
+    expect: {
+        var obj = {
+            x: 1,
+            method() {
+                this.s = "PASS";
+            },
+            get g() {
+                return this.x;
+            },
+            set s(value) {
+                this.x = value;
+            }
+        };
+        obj.method();
+        console.log(obj.g);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+issue_2554_2: {
+    options = {
+        computed_props: true,
+        evaluate: true,
+    }
+    input: {
+        var instance = new class {
+            constructor() {
+                this.x = 2;
+            }
+            ["method" + ""]() {
+                this.s = "PASS";
+            }
+            get ["g" + ""]() {
+                return this.x;
+            }
+            set ["s" + ""](value) {
+                this.x = value;
+            }
+        }();
+        instance.method();
+        console.log(instance.g);
+    }
+    expect: {
+        var instance = new class {
+            constructor() {
+                this.x = 2;
+            }
+            method() {
+                this.s = "PASS";
+            }
+            get g() {
+                return this.x;
+            }
+            set s(value) {
+                this.x = value;
+            }
+        }();
+        instance.method();
+        console.log(instance.g);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_2554_3: {
+    options = {
+        computed_props: true,
+        evaluate: true,
+    }
+    input: {
+        var foo = {
+            [1 + 0]: 1,
+            [2 + 0]() {
+                this[4] = "PASS";
+            },
+            get [3 + 0]() {
+                return this[1];
+            },
+            set [4 + 0](value) {
+                this[1] = value;
+            }
+        };
+        foo[2]();
+        console.log(foo[3]);
+    }
+    expect: {
+        var foo = {
+            1: 1,
+            2() {
+                this[4] = "PASS";
+            },
+            get 3() {
+                return this[1];
+            },
+            set 4(value) {
+                this[1] = value;
+            }
+        };
+        foo[2]();
+        console.log(foo[3]);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+issue_2554_4: {
+    options = {
+        computed_props: true,
+        evaluate: true,
+    }
+    input: {
+        var bar = new class {
+            constructor() {
+                this[1] = 2;
+            }
+            [2 + 0]() {
+                this[4] = "PASS";
+            }
+            get [3 + 0]() {
+                return this[1];
+            }
+            set [4 + 0](value) {
+                this[1] = value;
+            }
+        }();
+        bar[2]();
+        console.log(bar[3]);
+    }
+    expect: {
+        var bar = new class {
+            constructor() {
+                this[1] = 2;
+            }
+            2() {
+                this[4] = "PASS";
+            }
+            get 3() {
+                return this[1];
+            }
+            set 4(value) {
+                this[1] = value;
+            }
+        }();
+        bar[2]();
+        console.log(bar[3]);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_2554_5: {
+    options = {
+        computed_props: true,
+        evaluate: true,
+    }
+    input: {
+        new class {
+            ["constructor"]() {
+                console.log("FAIL");
+            }
+            "constructor"() {
+                console.log("PASS");
+            }
+        }();
+    }
+    expect: {
+        new class {
+            ["constructor"]() {
+                console.log("FAIL");
+            }
+            constructor() {
+                console.log("PASS");
+            }
+        }();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}