diff --git a/src/parser/expression.js b/src/parser/expression.js
index 2f00e5d1a5..6159d306f6 100644
--- a/src/parser/expression.js
+++ b/src/parser/expression.js
@@ -885,7 +885,6 @@ pp.parseFunctionBody = function (node, allowExpression) {
   // are not repeated, and it does not try to bind the words `eval`
   // or `arguments`.
   let checkLVal = this.state.strict;
-  let checkLValStrict = false;
   let isStrict = false;
 
   // arrow function
@@ -897,7 +896,6 @@ pp.parseFunctionBody = function (node, allowExpression) {
       if (directive.value.value === "use strict") {
         isStrict = true;
         checkLVal = true;
-        checkLValStrict = true;
         break;
       }
     }
@@ -911,11 +909,14 @@ pp.parseFunctionBody = function (node, allowExpression) {
   if (checkLVal) {
     let nameHash = Object.create(null);
     let oldStrict = this.state.strict;
-    if (checkLValStrict) this.state.strict = true;
+    if (isStrict) this.state.strict = true;
     if (node.id) {
       this.checkLVal(node.id, true);
     }
     for (let param of (node.params: Array<Object>)) {
+      if (isStrict && param.type !== "Identifier") {
+        this.raise(param.start, "Non-simple parameter in strict mode");
+      }
       this.checkLVal(param, true, nameHash);
     }
     this.state.strict = oldStrict;
diff --git a/test/fixtures/es2016/simple-parameter-list/array-pattern-default/actual.js b/test/fixtures/es2016/simple-parameter-list/array-pattern-default/actual.js
new file mode 100644
index 0000000000..ed9b603687
--- /dev/null
+++ b/test/fixtures/es2016/simple-parameter-list/array-pattern-default/actual.js
@@ -0,0 +1,3 @@
+function a([ option1, option2 ] = []) {
+  "use strict";
+}
diff --git a/test/fixtures/es2016/simple-parameter-list/array-pattern-default/options.json b/test/fixtures/es2016/simple-parameter-list/array-pattern-default/options.json
new file mode 100644
index 0000000000..5a257f4e5d
--- /dev/null
+++ b/test/fixtures/es2016/simple-parameter-list/array-pattern-default/options.json
@@ -0,0 +1,3 @@
+{
+  "throws": "Non-simple parameter in strict mode (1:11)"
+}
diff --git a/test/fixtures/es2016/simple-parameter-list/array-pattern/actual.js b/test/fixtures/es2016/simple-parameter-list/array-pattern/actual.js
new file mode 100644
index 0000000000..2d5d9ede78
--- /dev/null
+++ b/test/fixtures/es2016/simple-parameter-list/array-pattern/actual.js
@@ -0,0 +1,3 @@
+function a([ option1, option2 ]) {
+  "use strict";
+}
diff --git a/test/fixtures/es2016/simple-parameter-list/array-pattern/options.json b/test/fixtures/es2016/simple-parameter-list/array-pattern/options.json
new file mode 100644
index 0000000000..5a257f4e5d
--- /dev/null
+++ b/test/fixtures/es2016/simple-parameter-list/array-pattern/options.json
@@ -0,0 +1,3 @@
+{
+  "throws": "Non-simple parameter in strict mode (1:11)"
+}
diff --git a/test/fixtures/es2016/simple-parameter-list/arrow-function-concise-body/actual.js b/test/fixtures/es2016/simple-parameter-list/arrow-function-concise-body/actual.js
new file mode 100644
index 0000000000..770cce6026
--- /dev/null
+++ b/test/fixtures/es2016/simple-parameter-list/arrow-function-concise-body/actual.js
@@ -0,0 +1 @@
+var a = (options = {}) => options;
diff --git a/test/fixtures/es2016/simple-parameter-list/arrow-function-concise-body/expected.json b/test/fixtures/es2016/simple-parameter-list/arrow-function-concise-body/expected.json
new file mode 100644
index 0000000000..647180b64a
--- /dev/null
+++ b/test/fixtures/es2016/simple-parameter-list/arrow-function-concise-body/expected.json
@@ -0,0 +1,170 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 34,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 34
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 34,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 34
+      }
+    },
+    "sourceType": "script",
+    "body": [
+      {
+        "type": "VariableDeclaration",
+        "start": 0,
+        "end": 34,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 34
+          }
+        },
+        "declarations": [
+          {
+            "type": "VariableDeclarator",
+            "start": 4,
+            "end": 33,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 4
+              },
+              "end": {
+                "line": 1,
+                "column": 33
+              }
+            },
+            "id": {
+              "type": "Identifier",
+              "start": 4,
+              "end": 5,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 4
+                },
+                "end": {
+                  "line": 1,
+                  "column": 5
+                },
+                "identifierName": "a"
+              },
+              "name": "a"
+            },
+            "init": {
+              "type": "ArrowFunctionExpression",
+              "start": 8,
+              "end": 33,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 8
+                },
+                "end": {
+                  "line": 1,
+                  "column": 33
+                }
+              },
+              "id": null,
+              "generator": false,
+              "expression": true,
+              "async": false,
+              "params": [
+                {
+                  "type": "AssignmentPattern",
+                  "start": 9,
+                  "end": 21,
+                  "loc": {
+                    "start": {
+                      "line": 1,
+                      "column": 9
+                    },
+                    "end": {
+                      "line": 1,
+                      "column": 21
+                    }
+                  },
+                  "left": {
+                    "type": "Identifier",
+                    "start": 9,
+                    "end": 16,
+                    "loc": {
+                      "start": {
+                        "line": 1,
+                        "column": 9
+                      },
+                      "end": {
+                        "line": 1,
+                        "column": 16
+                      },
+                      "identifierName": "options"
+                    },
+                    "name": "options"
+                  },
+                  "right": {
+                    "type": "ObjectExpression",
+                    "start": 19,
+                    "end": 21,
+                    "loc": {
+                      "start": {
+                        "line": 1,
+                        "column": 19
+                      },
+                      "end": {
+                        "line": 1,
+                        "column": 21
+                      }
+                    },
+                    "properties": []
+                  }
+                }
+              ],
+              "body": {
+                "type": "Identifier",
+                "start": 26,
+                "end": 33,
+                "loc": {
+                  "start": {
+                    "line": 1,
+                    "column": 26
+                  },
+                  "end": {
+                    "line": 1,
+                    "column": 33
+                  },
+                  "identifierName": "options"
+                },
+                "name": "options"
+              }
+            }
+          }
+        ],
+        "kind": "var"
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/test/fixtures/es2016/simple-parameter-list/arrow-function/actual.js b/test/fixtures/es2016/simple-parameter-list/arrow-function/actual.js
new file mode 100644
index 0000000000..eecf8d53da
--- /dev/null
+++ b/test/fixtures/es2016/simple-parameter-list/arrow-function/actual.js
@@ -0,0 +1,3 @@
+var a = (options = {}) => {
+  "use strict";
+};
diff --git a/test/fixtures/es2016/simple-parameter-list/arrow-function/options.json b/test/fixtures/es2016/simple-parameter-list/arrow-function/options.json
new file mode 100644
index 0000000000..2e6ae0771c
--- /dev/null
+++ b/test/fixtures/es2016/simple-parameter-list/arrow-function/options.json
@@ -0,0 +1,3 @@
+{
+  "throws": "Non-simple parameter in strict mode (1:9)"
+}
diff --git a/test/fixtures/es2016/simple-parameter-list/async-arrow-function-concise-body/actual.js b/test/fixtures/es2016/simple-parameter-list/async-arrow-function-concise-body/actual.js
new file mode 100644
index 0000000000..4c592c16b6
--- /dev/null
+++ b/test/fixtures/es2016/simple-parameter-list/async-arrow-function-concise-body/actual.js
@@ -0,0 +1 @@
+var a = async (options = {}) => options;
diff --git a/test/fixtures/es2016/simple-parameter-list/async-arrow-function-concise-body/expected.json b/test/fixtures/es2016/simple-parameter-list/async-arrow-function-concise-body/expected.json
new file mode 100644
index 0000000000..419b4797ef
--- /dev/null
+++ b/test/fixtures/es2016/simple-parameter-list/async-arrow-function-concise-body/expected.json
@@ -0,0 +1,170 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 40,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 40
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 40,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 40
+      }
+    },
+    "sourceType": "script",
+    "body": [
+      {
+        "type": "VariableDeclaration",
+        "start": 0,
+        "end": 40,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 40
+          }
+        },
+        "declarations": [
+          {
+            "type": "VariableDeclarator",
+            "start": 4,
+            "end": 39,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 4
+              },
+              "end": {
+                "line": 1,
+                "column": 39
+              }
+            },
+            "id": {
+              "type": "Identifier",
+              "start": 4,
+              "end": 5,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 4
+                },
+                "end": {
+                  "line": 1,
+                  "column": 5
+                },
+                "identifierName": "a"
+              },
+              "name": "a"
+            },
+            "init": {
+              "type": "ArrowFunctionExpression",
+              "start": 8,
+              "end": 39,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 8
+                },
+                "end": {
+                  "line": 1,
+                  "column": 39
+                }
+              },
+              "id": null,
+              "generator": false,
+              "expression": true,
+              "async": true,
+              "params": [
+                {
+                  "type": "AssignmentPattern",
+                  "start": 15,
+                  "end": 27,
+                  "loc": {
+                    "start": {
+                      "line": 1,
+                      "column": 15
+                    },
+                    "end": {
+                      "line": 1,
+                      "column": 27
+                    }
+                  },
+                  "left": {
+                    "type": "Identifier",
+                    "start": 15,
+                    "end": 22,
+                    "loc": {
+                      "start": {
+                        "line": 1,
+                        "column": 15
+                      },
+                      "end": {
+                        "line": 1,
+                        "column": 22
+                      },
+                      "identifierName": "options"
+                    },
+                    "name": "options"
+                  },
+                  "right": {
+                    "type": "ObjectExpression",
+                    "start": 25,
+                    "end": 27,
+                    "loc": {
+                      "start": {
+                        "line": 1,
+                        "column": 25
+                      },
+                      "end": {
+                        "line": 1,
+                        "column": 27
+                      }
+                    },
+                    "properties": []
+                  }
+                }
+              ],
+              "body": {
+                "type": "Identifier",
+                "start": 32,
+                "end": 39,
+                "loc": {
+                  "start": {
+                    "line": 1,
+                    "column": 32
+                  },
+                  "end": {
+                    "line": 1,
+                    "column": 39
+                  },
+                  "identifierName": "options"
+                },
+                "name": "options"
+              }
+            }
+          }
+        ],
+        "kind": "var"
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/test/fixtures/es2016/simple-parameter-list/async-arrow-function/actual.js b/test/fixtures/es2016/simple-parameter-list/async-arrow-function/actual.js
new file mode 100644
index 0000000000..a36e097d8e
--- /dev/null
+++ b/test/fixtures/es2016/simple-parameter-list/async-arrow-function/actual.js
@@ -0,0 +1,3 @@
+var a = async (options = {}) => {
+  "use strict";
+};
diff --git a/test/fixtures/es2016/simple-parameter-list/async-arrow-function/options.json b/test/fixtures/es2016/simple-parameter-list/async-arrow-function/options.json
new file mode 100644
index 0000000000..0c31636171
--- /dev/null
+++ b/test/fixtures/es2016/simple-parameter-list/async-arrow-function/options.json
@@ -0,0 +1,3 @@
+{
+  "throws": "Non-simple parameter in strict mode (1:15)"
+}
diff --git a/test/fixtures/es2016/simple-parameter-list/async-function/actual.js b/test/fixtures/es2016/simple-parameter-list/async-function/actual.js
new file mode 100644
index 0000000000..639b9e9289
--- /dev/null
+++ b/test/fixtures/es2016/simple-parameter-list/async-function/actual.js
@@ -0,0 +1,3 @@
+async function a(options = {}) {
+  "use strict";
+}
diff --git a/test/fixtures/es2016/simple-parameter-list/async-function/options.json b/test/fixtures/es2016/simple-parameter-list/async-function/options.json
new file mode 100644
index 0000000000..ff8a46ae1a
--- /dev/null
+++ b/test/fixtures/es2016/simple-parameter-list/async-function/options.json
@@ -0,0 +1,3 @@
+{
+  "throws": "Non-simple parameter in strict mode (1:17)"
+}
diff --git a/test/fixtures/es2016/simple-parameter-list/default/actual.js b/test/fixtures/es2016/simple-parameter-list/default/actual.js
new file mode 100644
index 0000000000..067bc955d5
--- /dev/null
+++ b/test/fixtures/es2016/simple-parameter-list/default/actual.js
@@ -0,0 +1,3 @@
+function a(options = {}) {
+  "use strict";
+}
diff --git a/test/fixtures/es2016/simple-parameter-list/default/options.json b/test/fixtures/es2016/simple-parameter-list/default/options.json
new file mode 100644
index 0000000000..5a257f4e5d
--- /dev/null
+++ b/test/fixtures/es2016/simple-parameter-list/default/options.json
@@ -0,0 +1,3 @@
+{
+  "throws": "Non-simple parameter in strict mode (1:11)"
+}
diff --git a/test/fixtures/es2016/simple-parameter-list/generator-function/actual.js b/test/fixtures/es2016/simple-parameter-list/generator-function/actual.js
new file mode 100644
index 0000000000..c63c64a049
--- /dev/null
+++ b/test/fixtures/es2016/simple-parameter-list/generator-function/actual.js
@@ -0,0 +1,3 @@
+function* a(options = {}) {
+  "use strict";
+}
diff --git a/test/fixtures/es2016/simple-parameter-list/generator-function/options.json b/test/fixtures/es2016/simple-parameter-list/generator-function/options.json
new file mode 100644
index 0000000000..65ff709b5f
--- /dev/null
+++ b/test/fixtures/es2016/simple-parameter-list/generator-function/options.json
@@ -0,0 +1,3 @@
+{
+  "throws": "Non-simple parameter in strict mode (1:12)"
+}
diff --git a/test/fixtures/es2016/simple-parameter-list/generator-method/actual.js b/test/fixtures/es2016/simple-parameter-list/generator-method/actual.js
new file mode 100644
index 0000000000..1f34608a28
--- /dev/null
+++ b/test/fixtures/es2016/simple-parameter-list/generator-method/actual.js
@@ -0,0 +1,5 @@
+var obj = {
+  * a(options = {}) {
+    "use strict";
+  }
+};
diff --git a/test/fixtures/es2016/simple-parameter-list/generator-method/options.json b/test/fixtures/es2016/simple-parameter-list/generator-method/options.json
new file mode 100644
index 0000000000..dd467e6578
--- /dev/null
+++ b/test/fixtures/es2016/simple-parameter-list/generator-method/options.json
@@ -0,0 +1,3 @@
+{
+  "throws": "Non-simple parameter in strict mode (2:6)"
+}
diff --git a/test/fixtures/es2016/simple-parameter-list/method/actual.js b/test/fixtures/es2016/simple-parameter-list/method/actual.js
new file mode 100644
index 0000000000..2090882ad4
--- /dev/null
+++ b/test/fixtures/es2016/simple-parameter-list/method/actual.js
@@ -0,0 +1,5 @@
+var obj = {
+  a(options = {}) {
+    "use strict";
+  }
+};
diff --git a/test/fixtures/es2016/simple-parameter-list/method/options.json b/test/fixtures/es2016/simple-parameter-list/method/options.json
new file mode 100644
index 0000000000..ac620235e9
--- /dev/null
+++ b/test/fixtures/es2016/simple-parameter-list/method/options.json
@@ -0,0 +1,3 @@
+{
+  "throws": "Non-simple parameter in strict mode (2:4)"
+}
diff --git a/test/fixtures/es2016/simple-parameter-list/object-pattern-default/actual.js b/test/fixtures/es2016/simple-parameter-list/object-pattern-default/actual.js
new file mode 100644
index 0000000000..236c9a3043
--- /dev/null
+++ b/test/fixtures/es2016/simple-parameter-list/object-pattern-default/actual.js
@@ -0,0 +1,3 @@
+function a({ option1, option2 } = {}) {
+  "use strict";
+}
diff --git a/test/fixtures/es2016/simple-parameter-list/object-pattern-default/options.json b/test/fixtures/es2016/simple-parameter-list/object-pattern-default/options.json
new file mode 100644
index 0000000000..5a257f4e5d
--- /dev/null
+++ b/test/fixtures/es2016/simple-parameter-list/object-pattern-default/options.json
@@ -0,0 +1,3 @@
+{
+  "throws": "Non-simple parameter in strict mode (1:11)"
+}
diff --git a/test/fixtures/es2016/simple-parameter-list/object-pattern/actual.js b/test/fixtures/es2016/simple-parameter-list/object-pattern/actual.js
new file mode 100644
index 0000000000..103c5af584
--- /dev/null
+++ b/test/fixtures/es2016/simple-parameter-list/object-pattern/actual.js
@@ -0,0 +1,3 @@
+function a({ option1, option2 }) {
+  "use strict";
+}
diff --git a/test/fixtures/es2016/simple-parameter-list/object-pattern/options.json b/test/fixtures/es2016/simple-parameter-list/object-pattern/options.json
new file mode 100644
index 0000000000..5a257f4e5d
--- /dev/null
+++ b/test/fixtures/es2016/simple-parameter-list/object-pattern/options.json
@@ -0,0 +1,3 @@
+{
+  "throws": "Non-simple parameter in strict mode (1:11)"
+}
diff --git a/test/fixtures/es2016/simple-parameter-list/rest/actual.js b/test/fixtures/es2016/simple-parameter-list/rest/actual.js
new file mode 100644
index 0000000000..f1ddd04a7d
--- /dev/null
+++ b/test/fixtures/es2016/simple-parameter-list/rest/actual.js
@@ -0,0 +1,3 @@
+function a(...options) {
+  "use strict";
+}
diff --git a/test/fixtures/es2016/simple-parameter-list/rest/options.json b/test/fixtures/es2016/simple-parameter-list/rest/options.json
new file mode 100644
index 0000000000..5a257f4e5d
--- /dev/null
+++ b/test/fixtures/es2016/simple-parameter-list/rest/options.json
@@ -0,0 +1,3 @@
+{
+  "throws": "Non-simple parameter in strict mode (1:11)"
+}
diff --git a/test/fixtures/esprima/declaration-function/empty-param/actual.js b/test/fixtures/esprima/declaration-function/empty-param/actual.js
deleted file mode 100644
index 860cafa480..0000000000
--- a/test/fixtures/esprima/declaration-function/empty-param/actual.js
+++ /dev/null
@@ -1 +0,0 @@
-function a([], []) {'use strict';}
diff --git a/test/fixtures/esprima/declaration-function/empty-param/expected.json b/test/fixtures/esprima/declaration-function/empty-param/expected.json
deleted file mode 100644
index 554eee01b4..0000000000
--- a/test/fixtures/esprima/declaration-function/empty-param/expected.json
+++ /dev/null
@@ -1,154 +0,0 @@
-{
-  "type": "File",
-  "start": 0,
-  "end": 34,
-  "loc": {
-    "start": {
-      "line": 1,
-      "column": 0
-    },
-    "end": {
-      "line": 1,
-      "column": 34
-    }
-  },
-  "program": {
-    "type": "Program",
-    "start": 0,
-    "end": 34,
-    "loc": {
-      "start": {
-        "line": 1,
-        "column": 0
-      },
-      "end": {
-        "line": 1,
-        "column": 34
-      }
-    },
-    "sourceType": "script",
-    "body": [
-      {
-        "type": "FunctionDeclaration",
-        "start": 0,
-        "end": 34,
-        "loc": {
-          "start": {
-            "line": 1,
-            "column": 0
-          },
-          "end": {
-            "line": 1,
-            "column": 34
-          }
-        },
-        "id": {
-          "type": "Identifier",
-          "start": 9,
-          "end": 10,
-          "loc": {
-            "start": {
-              "line": 1,
-              "column": 9
-            },
-            "end": {
-              "line": 1,
-              "column": 10
-            }
-          },
-          "name": "a"
-        },
-        "generator": false,
-        "expression": false,
-        "params": [
-          {
-            "type": "ArrayPattern",
-            "start": 11,
-            "end": 13,
-            "loc": {
-              "start": {
-                "line": 1,
-                "column": 11
-              },
-              "end": {
-                "line": 1,
-                "column": 13
-              }
-            },
-            "elements": []
-          },
-          {
-            "type": "ArrayPattern",
-            "start": 15,
-            "end": 17,
-            "loc": {
-              "start": {
-                "line": 1,
-                "column": 15
-              },
-              "end": {
-                "line": 1,
-                "column": 17
-              }
-            },
-            "elements": []
-          }
-        ],
-        "body": {
-          "type": "BlockStatement",
-          "start": 19,
-          "end": 34,
-          "loc": {
-            "start": {
-              "line": 1,
-              "column": 19
-            },
-            "end": {
-              "line": 1,
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\ No newline at end of file