When performing autocompletion, when I select a suggestion then the editor should merge the input value with what is currently there.

Suppose I have the following classes:

 class Bar { ... }

 class FooBar { ... }

And some code:

 Bar bar = new Bar();

Suppose I wish to change the type of Foo to FooBar. I place the caret at the start of the line and hit CTRL+SPACE, and type "Fo":

 |Bar bar = new Bar();
 ^ suggested "FooBar"

If I hit enter on the suggestion, the following code is inserted:

 FooBarBar bar = new Bar();

The autocompleter should have detecteded that the rest of "FooBar" is "Bar" which follows the caret, and hence inserted:

 FooBar bar = new Bar();

Conceptually this should simply a case of determining what text remains to be inserted after what has been typed so far ("oBar"), and subtracting from the end of this what is currently typed in ("Bar"), breaking on a space.

This should work on classes, variables, and other types of data with lookups.