Fix one if cleanup to watch for PatternInstanceof nodes

[jjohnstn]

• fixes Single if cleanup should not concatenate instanceofs that use pattern matching #1200
• add new PatternInstanceof logic to OneIfRatherThanDuplicateBlocksThatFallThroughFixCore
• add new test to CleanUpTest16

What it does

Fixes single if cleanup to handle case of pattern instanceof expressions.

How to test

See issue or new test.

Author checklist

• I have thoroughly tested my changes
• The change is following the coding conventions
• I have signed the Eclipse Contributor Agreement (ECA)

[dg444]

This issue is not fixed in Eclipse 4.34.0 2024-12.
Example1:

if (number instanceof Long n) {
return n.toString();
}
else if (number instanceof Float n) {
return n.toString();
}
else if (number instanceof Double n) {
return n.toString();
}

=> fails to compile:

if ((number instanceof Long n) || (number instanceof Float n) || (number instanceof Double n)) {
return n.toString();
}

Example 2:

if (e instanceof IOException io)
throw io;
else if (e.getCause() instanceof IOException io)
throw io;

=> fails to compile:

f ((e instanceof IOException io) || (e.getCause() instanceof IOException io))
throw io;

[dg444]

For more information see https://bugs.eclipse.org/bugs/show_bug.cgi?id=570171

[jjohnstn]

This has been fixed. There are 2 cleanups that create one if. One combines multiple if statements and the other merges conditions of an if/else if/else statement. The first cleanup was fixed in March by this PR. The second cleanup has just been fixed for 2025-03 M2. See #1200 for details on the new PR.