Infer types for method calls on immediately instantiated objects

[vinistock]

Motivation

Closes #2994

This PR adds inference for methods invoked directly on an object instantiation. It's fairly easy to add, so I think it's worth getting it done.

Implementation

When the receiver of a method call is another method call using new, we infer the type of the constant receiver and then return the attached version of it. For example:

# In this case, `Foo::<Class:Foo>` is the receiver of `new`, but new will return an
# object. Thus the right type is the attached class, which is `Foo`
Foo.new.something

The only exception is if the method new was overridden, which is valid in Ruby. We cannot guarantee that the override actually returns a new object of the class, so it's better to not infer anything in those cases.

Automated Tests

Added tests.

[vinistock]

• Infer types for method calls on immediately instantiated objects #3007 👈 (View in Graphite)
• main

This stack of pull requests is managed by Graphite. Learn more about stacking.

[andyw8]

Nice enhancement. Can we also make a note of this in the docs to help users understand why completions may or may not be available.

[vinistock]

Can we also make a note of this in the docs to help users understand why completions may or may not be available.

@andyw8 a note of what exactly? How we infer the type for new?

[andyw8]

I'm thinking something like:

Due to Ruby being a dynamically-typed language, completions are only available when we know the type of the receiver, for example:

• methods invoked directly on a singleton class
• methods invoked on a literal
• methods invoked immediately after a instantiating an object with new

[andyw8]

Note is good, LGTM.

[vinistock]

Merge activity

• Jan 6, 6:12 PM EST: A user merged this pull request with Graphite.