diff --git a/test/input/pr-3040/input.js b/test/input/pr-3040/input.js
new file mode 100644
index 00000000..6515dcbd
--- /dev/null
+++ b/test/input/pr-3040/input.js
@@ -0,0 +1,11 @@
+function _toConsumableArray(arr) { if (Array.isArray(arr)) { for (var i = 0, arr2 = Array(arr.length); i < arr.length; i++) { arr2[i] = arr[i]; } return arr2; } else { return Array.from(arr); } }
+
+var _require = require("bar"),
+    foo = _require.foo;
+
+var _require2 = require("world"),
+    hello = _require2.hello;
+
+foo.x.apply(foo, _toConsumableArray(foo.y(hello.z)));
+
+//# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/test/input/pr-3040/input.js.map b/test/input/pr-3040/input.js.map
new file mode 100644
index 00000000..f0883e22
--- /dev/null
+++ b/test/input/pr-3040/input.js.map
@@ -0,0 +1 @@
+{"version":3,"sources":["input2.js"],"names":["require","foo","hello","x","apply","_toConsumableArray","y","z"],"mappings":"kLAAcA,QAAQ,OAAfC,aAAAA,kBACSD,QAAQ,SAAjBE,gBAAAA,MAEPD,IAAIE,EAAJC,MAAAH,IAAAI,mBAASJ,IAAIK,EAAEJ,MAAMK","sourcesContent":["const {foo} = require(\"bar\");\nconst {hello} = require(\"world\");\n\nfoo.x(...foo.y(hello.z));\n"]}
\ No newline at end of file
diff --git a/test/input/pr-3040/pipe.js b/test/input/pr-3040/pipe.js
new file mode 100644
index 00000000..c675fa97
--- /dev/null
+++ b/test/input/pr-3040/pipe.js
@@ -0,0 +1,9 @@
+var fs = require("fs");
+
+// Timeout to offset uglify loading in the test suite
+setTimeout(function() {
+    fs.writeFileSync("test/input/pr-3040/input.js.map", '{"version":3,"sources":["input2.js"],"names":[],"mappings":";;eAAc,QAAQ,KAAR,C;IAAP,G,YAAA,G;;gBACS,QAAQ,OAAR,C;IAAT,K,aAAA,K;;AAEP,IAAI,CAAJ,+BAAS,IAAI,CAAJ,CAAM,MAAM,CAAZ,CAAT","file":"input.js","sourcesContent":["const {foo} = require(\\"bar\\");\\nconst {hello} = require(\\"world\\");\\n\\nfoo.x(...foo.y(hello.z));\\n"]}');
+
+    var fileContents = fs.readFileSync("test/input/pr-3040/input.js");
+    process.stdout.write(fileContents, "utf8");
+}, 100);
diff --git a/test/mocha/cli.js b/test/mocha/cli.js
index 10f0465a..b7b09899 100644
--- a/test/mocha/cli.js
+++ b/test/mocha/cli.js
@@ -94,6 +94,28 @@ describe("bin/uglifyjs", function () {
             done();
         });
     });
+    it("should not load the source map before it fully receives the JS source", function(done) {
+        var command = [
+            '"' + process.argv[0] + '" test/input/pr-3040/pipe.js |', uglifyjscmd,
+            "--source-map", "content=test/input/pr-3040/input.js.map",
+            "--source-map", "url=inline"
+        ].join(" ");
+        
+        exec(command, function(err, stdout) {
+            if (err) throw err;
+            
+            // Revert input file to initial state for future test validity
+            require("fs").writeFileSync("test/input/pr-3040/input.js.map", '{"version":3,"sources":["input2.js"],"names":["require","foo","hello","x","apply","_toConsumableArray","y","z"],"mappings":"kLAAcA,QAAQ,OAAfC,aAAAA,kBACSD,QAAQ,SAAjBE,gBAAAA,MAEPD,IAAIE,EAAJC,MAAAH,IAAAI,mBAASJ,IAAIK,EAAEJ,MAAMK","sourcesContent":["const {foo} = require(\\"bar\\");\\nconst {hello} = require(\\"world\\");\\n\\nfoo.x(...foo.y(hello.z));\\n"]}');
+            
+            assert.strictEqual(stdout, [
+                'function _toConsumableArray(arr){if(Array.isArray(arr)){for(var i=0,arr2=Array(arr.length);i<arr.length;i++){arr2[i]=arr[i]}return arr2}else{return Array.from(arr)}}var _require=require("bar"),foo=_require.foo;var _require2=require("world"),hello=_require2.hello;foo.x.apply(foo,_toConsumableArray(foo.y(hello.z)));\n',
+                "//# sourceMappingURL=data:application/json;charset=utf-8;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbImlucHV0Mi5qcyJdLCJuYW1lcyI6WyJyZXF1aXJlIiwiZm9vIiwiaGVsbG8iLCJ4IiwiYXBwbHkiLCJfdG9Db2",
+                "5zdW1hYmxlQXJyYXkiLCJ5IiwieiJdLCJtYXBwaW5ncyI6ImtMQUFjQSxRQUFRLE9BQWZDLGFBQUFBLGtCQUNTRCxRQUFRLFNBQWpCRSxnQkFBQUEsTUFFUEQsSUFBSUUsRUFBSkMsTUFBQUgsSUFBQUksbUJBQVNKLElBQUlLLEVBQUVKLE1B",
+                "QU1LIiwic291cmNlc0NvbnRlbnQiOlsiY29uc3Qge2Zvb30gPSByZXF1aXJlKFwiYmFyXCIpO1xuY29uc3Qge2hlbGxvfSA9IHJlcXVpcmUoXCJ3b3JsZFwiKTtcblxuZm9vLngoLi4uZm9vLnkoaGVsbG8ueikpO1xuIl19\n"
+            ].join(""));
+            done();
+        });
+    });
     it("Should work with --keep-fnames (mangle only)", function (done) {
         var command = uglifyjscmd + ' test/input/issue-1431/sample.js --keep-fnames -m';