From 56f4b2eea43537c8cde20db63b4b2b3592dac8af Mon Sep 17 00:00:00 2001
From: Daniel Rosenwasser <Daniel.Rosenwasser@microsoft.com>
Date: Tue, 10 Apr 2018 16:12:00 -0700
Subject: [PATCH] Provide an error when using 'import.meta' without setting
 'esnext'.

---
 src/compiler/checker.ts              | 15 +++++++++++----
 src/compiler/diagnosticMessages.json |  4 ++++
 2 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 444a23881c9..b2e4e3b9377 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -18702,10 +18702,7 @@ namespace ts {
             }
 
             if (node.keywordToken === SyntaxKind.ImportKeyword) {
-                const file = getSourceFileOfNode(node);
-                Debug.assert(!!(file.flags & NodeFlags.PossiblyContainsImportMeta), "Containing file is missing import meta node flag.");
-                Debug.assert(!!file.externalModuleIndicator, "Containing file should be a module.");
-                return node.name.escapedText === "meta" ? getGlobalImportMetaType() : unknownType;
+                return checkImportMetaProperty(node);
             }
         }
 
@@ -18725,6 +18722,16 @@ namespace ts {
             }
         }
 
+        function checkImportMetaProperty(node: MetaProperty) {
+            if (languageVersion < ScriptTarget.ESNext && modulekind < ModuleKind.ESNext) {
+                error(node, Diagnostics.The_import_meta_meta_property_is_only_allowed_using_ESNext_for_the_target_and_module_compiler_options);
+            }
+            const file = getSourceFileOfNode(node);
+            Debug.assert(!!(file.flags & NodeFlags.PossiblyContainsImportMeta), "Containing file is missing import meta node flag.");
+            Debug.assert(!!file.externalModuleIndicator, "Containing file should be a module.");
+            return node.name.escapedText === "meta" ? getGlobalImportMetaType() : unknownType;
+        }
+
         function getTypeOfParameter(symbol: Symbol) {
             const type = getTypeOfSymbol(symbol);
             if (strictNullChecks) {
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index 69a90fbabf5..b91165ea17b 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -967,6 +967,10 @@
         "category": "Error",
         "code": 1342
     },
+    "The 'import.meta' meta-property is only allowed using 'ESNext' for the 'target' and 'module' compiler options.": {
+        "category": "Error",
+        "code": 1343
+    },
 
     "Duplicate identifier '{0}'.": {
         "category": "Error",