[SR-436] Parse failure that shouldn’t be

[dabrahams]

Previous ID	SR-436
Radar	None
Original Reporter	@dabrahams
Type	Bug

Additional Detail from JIRA

Votes	0
Component/s	Compiler
Labels	Bug, Parser
Assignee	None
Priority	Medium

md5: 949afa5de508847771a1512d49cf0f05

Issue Description:

In 16c0d65,

1 as Int16 << 7

yields an “Expected type” failure, but shouldn’t.

[Dante-Broggi]

Interestingly, the provided code still produces the same error in the Xcode 9.4.1 toolchain.

[AnthonyLatsis]

The problem is that parseTypeIdentifier does an unconditional startsWithLess check for whether to anticipate a generic parameter list. Happens to be a great starter bug.