Rollup merge of #53360 - PramodBisht:issue/51602, r=estebank

Addressed #51602

Fixed #51602
r? @estebank

here I have addressed the case where `in` was not expected right after `if` block. Speaking of `type ascription` I am not sure if this the best approach which I have implemented. Plus I think one more test case can be added to test `type-ascription` case, though I don't have any at this point of time. I will ping you again if all existing testcases pass.

diff --cc src/libsyntax/parse/parser.rs
Simple merge