task project!==p works but task project==p does not

#### To report a bug...

I have a project who's name is a substring of another project's name. I am trying to list just tasks in the task and can not use the syntax project:p as that matches tasks in project:pp as well. I have used project!==p to get tasks not in project p, so I figured project==p would do the opposite, but it does not. Is it supposed to or is there a different way to list tasks in only project p?

* What command(s) did you run?
```task project==p```
* What did you expect to happen?
To see al tasks contained in project p
* What actually happened?
```
[task next ( project==p )]
No matches.
```
* Paste the output of the ```task diag``` command.
```

task 2.5.1
Platform: Linux

Compiler
Version: 8.2.1 20180831
Caps: +stdc +stdc_hosted +LP64 +c8 +i32 +l64 +vp64 +time_t64
Compliance: C++11

Build Features
Built: Nov 9 2018 23:33:36
CMake: 3.12.4
libuuid: libuuid + uuid_unparse_lower
libgnutls: 3.5.19
Build type:

Configuration
File: /home/shanks/.taskrc (found), 1466 bytes, mode 100644
Data: /home/shanks/.task (found), dir, mode 40755
Locking: Enabled
GC: Enabled
$EDITOR: /usr/bin/vim
Server:
Trust: strict
Certificate: , not readable, 0 bytes
Key: , not readable, 0 bytes
Ciphers: NORMAL
Creds:

Hooks
System: Enabled
Location: /home/shanks/.task/hooks
Active: on-modify.timewarrior (executable)
Inactive:

Tests
$TERM: rxvt-unicode-256color (324x106)
Dups: Scanned 64 tasks for duplicate UUIDs:
No duplicates found
Broken ref: Scanned 64 tasks for broken references:
No broken references found
```
#### To request a feature...

* Clearly describe the feature.
* Clearly state the use case. We are only interested in use cases, do not waste time with implementation details or suggested syntax.
* Please see our notes on [How to request a feature](https://taskwarrior.org/docs/features.html)