tests/cases/conformance/es6/variableDeclarations/VariableDeclaration7_es6.ts(1,1): error TS1153: 'let' declarations are only available when targeting ECMAScript 6 and higher.
==== tests/cases/conformance/es6/variableDeclarations/VariableDeclaration7_es6.ts (1 errors) ====
let a
~~~
!!! error TS1153: 'let' declarations are only available when targeting ECMAScript 6 and higher.