support rest parameters (#4515)

3 files changed, 501 insertions, 14 deletions

diff --git a/test/compress/async.js b/test/compress/awaits.js
index 7ae753fb..7ae753fb 100644
--- a/test/compress/async.js
+++ b/test/compress/awaits.js
diff --git a/test/compress/rests.js b/test/compress/rests.js
new file mode 100644
index 00000000..1a27860d
--- /dev/null
+++ b/test/compress/rests.js
@@ -0,0 +1,487 @@
+arrow_1: {
+    input: {
+        console.log.apply(console, ((...a) => a)("PASS", 42));
+    }
+    expect_exact: 'console.log.apply(console,((...a)=>a)("PASS",42));'
+    expect_stdout: "PASS 42"
+    node_version: ">=6"
+}
+
+arrow_2: {
+    input: {
+        console.log.apply(console, ((a, ...b) => b)("FAIL", "PASS", 42));
+    }
+    expect_exact: 'console.log.apply(console,((a,...b)=>b)("FAIL","PASS",42));'
+    expect_stdout: "PASS 42"
+    node_version: ">=6"
+}
+
+arrow_destructured_array_1: {
+    input: {
+        console.log.apply(console, (([ ...a ]) => a)("PASS"));
+    }
+    expect_exact: 'console.log.apply(console,(([...a])=>a)("PASS"));'
+    expect_stdout: "P A S S"
+    node_version: ">=6"
+}
+
+arrow_destructured_array_2: {
+    input: {
+        console.log.apply(console, (([ a, ...b ]) => b)([ "FAIL", "PASS", 42 ]));
+    }
+    expect_exact: 'console.log.apply(console,(([a,...b])=>b)(["FAIL","PASS",42]));'
+    expect_stdout: "PASS 42"
+    node_version: ">=6"
+}
+
+arrow_destructured_array_3: {
+    input: {
+        console.log((([ [ ...a ] = "FAIL" ]) => a)([ "PASS" ]).join("|"));
+    }
+    expect_exact: 'console.log((([[...a]="FAIL"])=>a)(["PASS"]).join("|"));'
+    expect_stdout: "P|A|S|S"
+    node_version: ">=6"
+}
+
+arrow_destructured_object_1: {
+    input: {
+        var f = ({ ...a }) => a, o = f({ PASS: 42 });
+        for (var k in o)
+            console.log(k, o[k]);
+    }
+    expect_exact: "var f=({...a})=>a,o=f({PASS:42});for(var k in o)console.log(k,o[k]);"
+    expect_stdout: "PASS 42"
+    node_version: ">=8"
+}
+
+arrow_destructured_object_2: {
+    input: {
+        var f = ({ FAIL: a, ...b }) => b, o = f({ PASS: 42, FAIL: null });
+        for (var k in o)
+            console.log(k, o[k]);
+    }
+    expect_exact: "var f=({FAIL:a,...b})=>b,o=f({PASS:42,FAIL:null});for(var k in o)console.log(k,o[k]);"
+    expect_stdout: "PASS 42"
+    node_version: ">=8"
+}
+
+arrow_destructured_object_3: {
+    input: {
+        var f = ([ { ...a } = [ "FAIL" ] ]) => a;
+        var o = f([ "PASS" ]);
+        for (var k in o)
+            console.log(k, o[k]);
+    }
+    expect_exact: 'var f=([{...a}=["FAIL"]])=>a;var o=f(["PASS"]);for(var k in o)console.log(k,o[k]);'
+    expect_stdout: [
+        "0 P",
+        "1 A",
+        "2 S",
+        "3 S",
+    ]
+    node_version: ">=8"
+}
+
+funarg_1: {
+    input: {
+        console.log.apply(console, function(...a) {
+            return a;
+        }("PASS", 42));
+    }
+    expect_exact: 'console.log.apply(console,function(...a){return a}("PASS",42));'
+    expect_stdout: "PASS 42"
+    node_version: ">=6"
+}
+
+funarg_2: {
+    input: {
+        console.log.apply(console, function(a, ...b) {
+            return b;
+        }("FAIL", "PASS", 42));
+    }
+    expect_exact: 'console.log.apply(console,function(a,...b){return b}("FAIL","PASS",42));'
+    expect_stdout: "PASS 42"
+    node_version: ">=6"
+}
+
+destructured_array_1: {
+    input: {
+        var [ ...a ] = [ "PASS", 42 ];
+        console.log.apply(console, a);
+    }
+    expect_exact: 'var[...a]=["PASS",42];console.log.apply(console,a);'
+    expect_stdout: "PASS 42"
+    node_version: ">=6"
+}
+
+destructured_array_2: {
+    input: {
+        var [ a, ...b ] = [ "FAIL", "PASS", 42 ];
+        console.log.apply(console, b);
+    }
+    expect_exact: 'var[a,...b]=["FAIL","PASS",42];console.log.apply(console,b);'
+    expect_stdout: "PASS 42"
+    node_version: ">=6"
+}
+
+destructured_object_1: {
+    input: {
+        var { ...a } = [ "FAIL", "PASS", 42 ];
+        console.log(a[1], a[2]);
+    }
+    expect_exact: 'var{...a}=["FAIL","PASS",42];console.log(a[1],a[2]);'
+    expect_stdout: "PASS 42"
+    node_version: ">=8"
+}
+
+destructured_object_2: {
+    input: {
+        var { 0: a, ...b } = [ "FAIL", "PASS", 42 ];
+        console.log(b[1], b[2]);
+    }
+    expect_exact: 'var{0:a,...b}=["FAIL","PASS",42];console.log(b[1],b[2]);'
+    expect_stdout: "PASS 42"
+    node_version: ">=8"
+}
+
+drop_fargs: {
+    options = {
+        keep_fargs: false,
+        rests: true,
+        unused: true,
+    }
+    input: {
+        console.log(function(a, ...b) {
+            return b[0];
+        }("FAIL", "PASS"));
+    }
+    expect: {
+        console.log(function(b) {
+            return b[0];
+        }([ "PASS" ]));
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+inline: {
+    options = {
+        inline: true,
+        toplevel: true,
+    }
+    input: {
+        console.log(function(a, ...[ b, c ]) {
+            return c + b + a;
+        }("SS", "A", "P"));
+    }
+    expect: {
+        console.log(([ a, ...[ b, c ] ] = [ "SS", "A", "P" ], c + b + a));
+        var a, b, c;
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+retain_var: {
+    options = {
+        unused: true,
+    }
+    input: {
+        var [ ...a ] = [ "PASS" ];
+        console.log(a[0]);
+    }
+    expect: {
+        var [ ...a ] = [ "PASS" ];
+        console.log(a[0]);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+reduce_destructured_array: {
+    options = {
+        reduce_vars: true,
+        rests: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var [ ...a ] = [ "PASS" ];
+        console.log(a[0]);
+    }
+    expect: {
+        console.log([ "PASS" ][0]);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+reduce_destructured_object: {
+    options = {
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var { ...a } = [ "PASS" ];
+        console.log(a[0]);
+    }
+    expect: {
+        var { ...a } = [ "PASS" ];
+        console.log(a[0]);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+retain_destructured_array: {
+    options = {
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var [ a, ...b ] = [ "FAIL", "PASS", 42 ];
+        console.log.apply(console, b);
+    }
+    expect: {
+        var [ , ...b ] = [ "FAIL", "PASS", 42 ];
+        console.log.apply(console, b);
+    }
+    expect_stdout: "PASS 42"
+    node_version: ">=6"
+}
+
+retain_destructured_object_1: {
+    options = {
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var { 0: a, ...b } = [ "FAIL", "PASS", 42 ];
+        for (var k in b)
+            console.log(k, b[k]);
+    }
+    expect: {
+        var { 0: a, ...b } = [ "FAIL", "PASS", 42 ];
+        for (var k in b)
+            console.log(k, b[k]);
+    }
+    expect_stdout: [
+        "1 PASS",
+        "2 42",
+    ]
+    node_version: ">=8"
+}
+
+retain_destructured_object_2: {
+    options = {
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var { foo: [ a ], ...b } = { foo: [ "FAIL" ], bar: "PASS", baz: 42 };
+        for (var k in b)
+            console.log(k, b[k]);
+    }
+    expect: {
+        var { foo: [], ...b } = { foo: [ "FAIL" ], bar: "PASS", baz: 42 };
+        for (var k in b)
+            console.log(k, b[k]);
+    }
+    expect_stdout: [
+        "bar PASS",
+        "baz 42",
+    ]
+    node_version: ">=8"
+}
+
+retain_funarg_destructured_array_1: {
+    options = {
+        inline: true,
+        keep_fargs: false,
+        pure_getters: "strict",
+        unused: true,
+    }
+    input: {
+        console.log((([ ...a ]) => a)([ "PASS" ])[0]);
+    }
+    expect: {
+        console.log((([ ...a ]) => a)([ "PASS" ])[0]);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+retain_funarg_destructured_array_2: {
+    options = {
+        unused: true,
+    }
+    input: {
+        console.log(function([ a, ...b ]) {
+            return b;
+        }("bar")[1]);
+    }
+    expect: {
+        console.log(function([ , ...b ]) {
+            return b;
+        }("bar")[1]);
+    }
+    expect_stdout: "r"
+    node_version: ">=6"
+}
+
+retain_funarg_destructured_object_1: {
+    options = {
+        inline: true,
+        keep_fargs: false,
+        pure_getters: "strict",
+        unused: true,
+    }
+    input: {
+        console.log((({ ...a }) => a)([ "PASS" ])[0]);
+    }
+    expect: {
+        console.log((({ ...a }) => a)([ "PASS" ])[0]);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+retain_funarg_destructured_object_2: {
+    options = {
+        unused: true,
+    }
+    input: {
+        console.log(function({ p: a, ... b }) {
+            return b;
+        }({ p: "FAIL" }).p || "PASS");
+    }
+    expect: {
+        console.log(function({ p: a, ... b }) {
+            return b;
+        }({ p: "FAIL" }).p || "PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+drop_unused_call_args_1: {
+    options = {
+        rests: true,
+        unused: true,
+    }
+    input: {
+        (function(...a) {
+            console.log(a[0]);
+        })(42, console.log("PASS"));
+    }
+    expect: {
+        (function(a) {
+            console.log(a[0]);
+        })([ 42, console.log("PASS") ]);
+    }
+    expect_stdout: [
+        "PASS",
+        "42",
+    ]
+    node_version: ">=6"
+}
+
+drop_unused_call_args_2: {
+    options = {
+        keep_fargs: false,
+        rests: true,
+        unused: true,
+    }
+    input: {
+        console.log(function(a, ...b) {
+            return b;
+        }(console).length);
+    }
+    expect: {
+        console.log(function(b) {
+            return b;
+        }((console, [])).length);
+    }
+    expect_stdout: "0"
+    node_version: ">=6"
+}
+
+merge_funarg: {
+    options = {
+        merge_vars: true,
+    }
+    input: {
+        (function(...a) {
+            var b = a.length;
+            console.log(b);
+        })();
+    }
+    expect: {
+        (function(...b) {
+            var b = b.length;
+            console.log(b);
+        })();
+    }
+    expect_stdout: "0"
+    node_version: ">=6"
+}
+
+merge_funarg_destructured_array: {
+    options = {
+        merge_vars: true,
+    }
+    input: {
+        (function([ ...a ]) {
+            var b = a.length;
+            console.log(b);
+        })([]);
+    }
+    expect: {
+        (function([ ...b ]) {
+            var b = b.length;
+            console.log(b);
+        })([]);
+    }
+    expect_stdout: "0"
+    node_version: ">=6"
+}
+
+merge_funarg_destructured_object: {
+    options = {
+        merge_vars: true,
+    }
+    input: {
+        (function({ ...a }) {
+            var b = a[0];
+            console.log(b);
+        })([ "PASS" ]);
+    }
+    expect: {
+        (function({ ...b }) {
+            var b = b[0];
+            console.log(b);
+        })([ "PASS" ]);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+keep_arguments: {
+    options = {
+        arguments: true,
+        keep_fargs: false,
+    }
+    input: {
+        (function(...[ {} ]) {
+            console.log(arguments[0]);
+        })("PASS");
+    }
+    expect: {
+        (function(...[ {} ]) {
+            console.log(arguments[0]);
+        })("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
diff --git a/test/compress/spread.js b/test/compress/spreads.js
index 944915fe..1e4dcbf6 100644
--- a/test/compress/spread.js
+++ b/test/compress/spreads.js
@@ -128,7 +128,7 @@ dont_inline: {
 do_inline: {
     options = {
         inline: true,
-        spread: true,
+        spreads: true,
     }
     input: {
         console.log(function(a) {
@@ -167,7 +167,7 @@ drop_empty_call_1: {
 drop_empty_call_2: {
     options = {
         side_effects: true,
-        spread: true,
+        spreads: true,
     }
     input: {
         (function() {})(...[ console.log("PASS") ]);
@@ -181,7 +181,7 @@ drop_empty_call_2: {
 
 convert_hole: {
     options = {
-        spread: true,
+        spreads: true,
     }
     input: {
         console.log(...[ "PASS", , 42 ]);
@@ -275,7 +275,7 @@ reduce_vars_2: {
 convert_setter: {
     options = {
         objects: true,
-        spread: true,
+        spreads: true,
     }
     input: {
         var o = {
@@ -419,7 +419,7 @@ keep_getter_4: {
 keep_accessor: {
     options = {
         objects: true,
-        spread: true,
+        spreads: true,
     }
     input: {
         var o = {
@@ -467,7 +467,7 @@ keep_accessor: {
 object_key_order_1: {
     options = {
         objects: true,
-        spread: true,
+        spreads: true,
     }
     input: {
         var o = {
@@ -497,7 +497,7 @@ object_key_order_1: {
 object_key_order_2: {
     options = {
         objects: true,
-        spread: true,
+        spreads: true,
     }
     input: {
         var o = {
@@ -527,7 +527,7 @@ object_key_order_2: {
 object_key_order_3: {
     options = {
         objects: true,
-        spread: true,
+        spreads: true,
     }
     input: {
         var o = {
@@ -557,7 +557,7 @@ object_key_order_3: {
 object_key_order_4: {
     options = {
         objects: true,
-        spread: true,
+        spreads: true,
     }
     input: {
         var o = {
@@ -587,7 +587,7 @@ object_key_order_4: {
 object_spread_array: {
     options = {
         objects: true,
-        spread: true,
+        spreads: true,
     }
     input: {
         var o = {
@@ -613,7 +613,7 @@ object_spread_array: {
 object_spread_string: {
     options = {
         objects: true,
-        spread: true,
+        spreads: true,
     }
     input: {
         var o = {
@@ -670,7 +670,7 @@ unused_var_side_effects: {
 issue_4329: {
     options = {
         objects: true,
-        spread: true,
+        spreads: true,
     }
     input: {
         console.log({
@@ -749,7 +749,7 @@ issue_4342: {
 issue_4345: {
     options = {
         objects: true,
-        spread: true,
+        spreads: true,
     }
     input: {
         console.log({
@@ -809,7 +809,7 @@ issue_4361: {
 issue_4363: {
     options = {
         objects: true,
-        spread: true,
+        spreads: true,
     }
     input: {
         ({