12 files changed, 82 insertions, 26 deletions
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index fcbd0e85e..584ddb3ed 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -187,7 +187,7 @@ function $DONE(arg) {
 
 ## Handling Errors and Negative Test Cases
 
-Expectations for **parsing errors** should be declared using [the `negative` frontmatter flag](#negative):
+Expectations for **parsing errors** should be declared using [the `negative` frontmatter flag](#negative). They must also include the exact `throw` statement specified in this example (in order to guarantee that implementations do not execute the code):
 
 ```javascript
 /*---
@@ -196,6 +196,8 @@ negative:
   type: SyntaxError
 ---*/
 
+throw "Test262: This statement should not be evaluated.";
+
 var var = var;
 ```
 
diff --git a/INTERPRETING.md b/INTERPRETING.md
index 4f837b78d..6c78fa67c 100644
--- a/INTERPRETING.md
+++ b/INTERPRETING.md
@@ -147,8 +147,7 @@ attribute is a YAML dictonary with two keys:
 
 - `phase` - the stage of the test interpretation process that the error is
   expected to be produced; either "early" (meaning, "prior to evaluation") or
-  "runtime" (meaning, "during evaluation"); in the case of "early", additional
-  test transformation may be required--see below
+  "runtime" (meaning, "during evaluation")
 - `type` - the name of the constructor of the expected error
 
 If a test configured with the `negative` attribute completes without throwing
@@ -167,14 +166,6 @@ negative:
 unresolvable;
 ```
 
-Consumers are free to assert the "early" phase as they see fit.
-
-For example, it is possible to insert a `throw` statement with a unique error
-type at the beginning of the test file. In this case, the statement should be
-inserted *after* the directive desribed in the section titled "Strict Mode"
-(where appropriate), though it must *not* be inserted for tests containing the
-"raw" flag.
-
 ### `includes`
 
 One or more files whose content must be evaluated in the test realm's global
diff --git a/tools/lint/lib/checks/frontmatter.py b/tools/lint/lib/checks/frontmatter.py
index a528f746a..b62f41935 100644
--- a/tools/lint/lib/checks/frontmatter.py
+++ b/tools/lint/lib/checks/frontmatter.py
@@ -29,14 +29,3 @@ class CheckFrontmatter(Check):
         unrecognized = fields - _VALID_FIELDS
         if len(unrecognized) > 0:
             return 'Unrecognized fields: %s' % ', '.join(list(unrecognized))
-
-        if 'negative' in meta:
-            negative = meta['negative']
-            if not isinstance(negative, dict):
-                return '"negative" must be a dictionary with fields "type" and "phase"'
-
-            if not 'type' in negative:
-                return '"negative" must specify a "type" field'
-
-            if not 'phase' in negative:
-                return '"negative" must specify a "phase" field'
diff --git a/tools/lint/lib/checks/negative.py b/tools/lint/lib/checks/negative.py
new file mode 100644
index 000000000..b1ae3e4fb
--- /dev/null
+++ b/tools/lint/lib/checks/negative.py
@@ -0,0 +1,27 @@
+import re
+from ..check import Check
+
+_THROW_STMT = re.compile(
+      r'^throw "Test262: This statement should not be evaluated\.";$',
+      re.MULTILINE)
+
+class CheckNegative(Check):
+    '''Ensure tests have the expected YAML-formatted metadata.'''
+    ID = 'NEGATIVE'
+
+    def run(self, name, meta, source):
+        if meta is None or meta.get('negative') is None:
+            return
+
+        negative = meta['negative']
+        if not isinstance(negative, dict):
+            return '"negative" must be a dictionary with fields "type" and "phase"'
+
+        if not 'type' in negative:
+            return '"negative" must specify a "type" field'
+
+        if not 'phase' in negative:
+            return '"negative" must specify a "phase" field'
+
+        if negative["phase"] == "early" and not _THROW_STMT.search(source):
+            return 'Negative tests of type "early" must include a `throw` statement'
diff --git a/tools/lint/lint.py b/tools/lint/lint.py
index 9cdbca474..09e22507a 100755
--- a/tools/lint/lint.py
+++ b/tools/lint/lint.py
@@ -9,6 +9,7 @@ from lib.collect_files import collect_files
 from lib.checks.features import CheckFeatures
 from lib.checks.frontmatter import CheckFrontmatter
 from lib.checks.license import CheckLicense
+from lib.checks.negative import CheckNegative
 from lib.eprint import eprint
 import lib.frontmatter
 import lib.whitelist
@@ -21,7 +22,10 @@ parser.add_argument('path',
         nargs='+',
         help='file name or directory of files to lint')
 
-checks = [CheckFrontmatter(), CheckFeatures('features.txt'), CheckLicense()]
+checks = [
+        CheckFrontmatter(), CheckFeatures('features.txt'), CheckLicense(),
+        CheckNegative()
+    ]
 
 def lint(file_names):
     errors = dict()
diff --git a/tools/lint/test/fixtures/negative_early_throw_bad_value.js b/tools/lint/test/fixtures/negative_early_throw_bad_value.js
new file mode 100644
index 000000000..22979c313
--- /dev/null
+++ b/tools/lint/test/fixtures/negative_early_throw_bad_value.js
@@ -0,0 +1,15 @@
+NEGATIVE
+^ expected errors | v input
+// Copyright (C) 2017 Mike Pennisi. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-assignment-operators-static-semantics-early-errors
+description: Minimal test
+negative:
+  type: SyntaxError
+  phase: early
+---*/
+
+throw "Test262: This statement should not be evaluated!";
+
+!!!
diff --git a/tools/lint/test/fixtures/frontmatter_negative_valid.js b/tools/lint/test/fixtures/negative_early_throw_missing.js
index f1b5cc05d..44a9a22dd 100644
--- a/tools/lint/test/fixtures/frontmatter_negative_valid.js
+++ b/tools/lint/test/fixtures/negative_early_throw_missing.js
@@ -1,3 +1,4 @@
+NEGATIVE
 ^ expected errors | v input
 // Copyright (C) 2017 Mike Pennisi. All rights reserved.
 // This code is governed by the BSD license found in the LICENSE file.
diff --git a/tools/lint/test/fixtures/frontmatter_negative_missing_phase.js b/tools/lint/test/fixtures/negative_missing_phase.js
index 8315882ca..e830d4238 100644
--- a/tools/lint/test/fixtures/frontmatter_negative_missing_phase.js
+++ b/tools/lint/test/fixtures/negative_missing_phase.js
@@ -1,4 +1,4 @@
-FRONTMATTER
+NEGATIVE
 ^ expected errors | v input
 // Copyright (C) 2017 Mike Pennisi. All rights reserved.
 // This code is governed by the BSD license found in the LICENSE file.
diff --git a/tools/lint/test/fixtures/frontmatter_negative_missing_type.js b/tools/lint/test/fixtures/negative_missing_type.js
index 6e3ec6551..8642c9124 100644
--- a/tools/lint/test/fixtures/frontmatter_negative_missing_type.js
+++ b/tools/lint/test/fixtures/negative_missing_type.js
@@ -1,4 +1,4 @@
-FRONTMATTER
+NEGATIVE
 ^ expected errors | v input
 // Copyright (C) 2017 Mike Pennisi. All rights reserved.
 // This code is governed by the BSD license found in the LICENSE file.
diff --git a/tools/lint/test/fixtures/frontmatter_negative_string.js b/tools/lint/test/fixtures/negative_string.js
index b11d19a3e..706f773a5 100644
--- a/tools/lint/test/fixtures/frontmatter_negative_string.js
+++ b/tools/lint/test/fixtures/negative_string.js
@@ -1,4 +1,4 @@
-FRONTMATTER
+NEGATIVE
 ^ expected errors | v input
 // Copyright (C) 2017 Mike Pennisi. All rights reserved.
 // This code is governed by the BSD license found in the LICENSE file.
diff --git a/tools/lint/test/fixtures/negative_valid_early.js b/tools/lint/test/fixtures/negative_valid_early.js
new file mode 100644
index 000000000..5b6c7a261
--- /dev/null
+++ b/tools/lint/test/fixtures/negative_valid_early.js
@@ -0,0 +1,14 @@
+^ expected errors | v input
+// Copyright (C) 2017 Mike Pennisi. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-assignment-operators-static-semantics-early-errors
+description: Minimal test
+negative:
+  type: SyntaxError
+  phase: early
+---*/
+
+throw "Test262: This statement should not be evaluated.";
+
+!!!
diff --git a/tools/lint/test/fixtures/negative_valid_runtime.js b/tools/lint/test/fixtures/negative_valid_runtime.js
new file mode 100644
index 000000000..ed4b056fd
--- /dev/null
+++ b/tools/lint/test/fixtures/negative_valid_runtime.js
@@ -0,0 +1,13 @@
+^ expected errors | v input
+// Copyright (C) 2017 Mike Pennisi. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-assignment-operators-static-semantics-early-errors
+description: Minimal test
+negative:
+  type: ReferenceError
+  phase: runtime
+---*/
+
+x;
+let x;