Type of Promise<T> is not validated

Given [this sample code](https://closure-compiler-debugger.appspot.com/#input0%3D%252F**%250A%2520*%2520%2540return%2520%257B!Promise%253Cboolean%253E%257D%250A%2520*%252F%250Afunction%2520a()%2520%257B%250A%2520%2520return%2520Promise.resolve().then(()%2520%253D%253E%2520'42')%253B%250A%257D%250A%250A%252F**%250A%2520*%2520%2540return%2520%257B!Promise%253Cboolean%253E%257D%250A%2520*%252F%250Afunction%2520b()%2520%257B%250A%2520%2520return%2520Promise.resolve().then(()%2520%253D%253E%2520Promise.resolve('42'))%253B%250A%257D%250A%250A%252F**%250A%2520*%2520%2540return%2520%257B!Promise%253Cboolean%253E%257D%250A%2520*%252F%250Afunction%2520c()%2520%257B%250A%2520%2520return%2520Promise.resolve('42')%253B%250A%257D%250A%26input1%26conformanceConfig%26externs%26refasterjs-template%26includeDefaultExterns%3D1%26CHECK_SYMBOLS%3D1%26MISSING_PROPERTIES%3D1%26TRANSPILE%3D1%26CHECK_TYPES%3D1%26CHECK_TYPES_NEW_INFERENCE%3D1%26CLOSURE_PASS%3D1%26PRESERVE_TYPE_ANNOTATIONS%3D1%26PRETTY_PRINT%3D1), all functions should show an error, but with NTI, none of them do, and with OTI, only one of them do.