check initialization of exported block scoped variables

src/compiler/checker.ts

@@ -610,8 +610,11 @@ namespace ts {
                 // block - scope variable and namespace module. However, only when we
                 // try to resolve name in /*1*/ which is used in variable position,
                 // we want to check for block- scoped
-                if (meaning & SymbolFlags.BlockScopedVariable && result.flags & SymbolFlags.BlockScopedVariable) {
-                    checkResolvedBlockScopedVariable(result, errorLocation);
+                if (meaning & SymbolFlags.BlockScopedVariable) {
+                    const exportOrLocalSymbol = getExportSymbolOfValueSymbolIfExported(result);
+                    if (exportOrLocalSymbol.flags & SymbolFlags.BlockScopedVariable) {
+                        checkResolvedBlockScopedVariable(exportOrLocalSymbol, errorLocation);
+                    }
                 }
             }
             return result;

tests/baselines/reference/exportedBlockScopedDeclarations.errors.txt

@@ -0,0 +1,23 @@
+tests/cases/compiler/exportedBlockScopedDeclarations.ts(1,13): error TS2448: Block-scoped variable 'foo' used before its declaration.
+tests/cases/compiler/exportedBlockScopedDeclarations.ts(2,20): error TS2448: Block-scoped variable 'bar' used before its declaration.
+tests/cases/compiler/exportedBlockScopedDeclarations.ts(4,15): error TS2448: Block-scoped variable 'bar' used before its declaration.
+tests/cases/compiler/exportedBlockScopedDeclarations.ts(7,22): error TS2448: Block-scoped variable 'bar' used before its declaration.
+
+
+==== tests/cases/compiler/exportedBlockScopedDeclarations.ts (4 errors) ====
+    const foo = foo; // compile error
+                ~~~
+!!! error TS2448: Block-scoped variable 'foo' used before its declaration.
+    export const bar = bar; // should be compile error
+                       ~~~
+!!! error TS2448: Block-scoped variable 'bar' used before its declaration.
+    function f() {
+      const bar = bar; // compile error
+                  ~~~
+!!! error TS2448: Block-scoped variable 'bar' used before its declaration.
+    }
+    namespace NS {
+      export const bar = bar; // should be compile error
+                         ~~~
+!!! error TS2448: Block-scoped variable 'bar' used before its declaration.
+    }

tests/baselines/reference/exportedBlockScopedDeclarations.js

@@ -0,0 +1,22 @@
+//// [exportedBlockScopedDeclarations.ts]
+const foo = foo; // compile error
+export const bar = bar; // should be compile error
+function f() {
+  const bar = bar; // compile error
+}
+namespace NS {
+  export const bar = bar; // should be compile error
+}
+
+//// [exportedBlockScopedDeclarations.js]
+define(["require", "exports"], function (require, exports) {
+    var foo = foo; // compile error
+    exports.bar = exports.bar; // should be compile error
+    function f() {
+        var bar = bar; // compile error
+    }
+    var NS;
+    (function (NS) {
+        NS.bar = NS.bar; // should be compile error
+    })(NS || (NS = {}));
+});

tests/cases/compiler/exportedBlockScopedDeclarations.ts

@@ -0,0 +1,9 @@
+// @module: amd
+const foo = foo; // compile error
+export const bar = bar; // should be compile error
+function f() {
+  const bar = bar; // compile error
+}
+namespace NS {
+  export const bar = bar; // should be compile error
+}