[Chapel Merge] Warn for misleading 'new' pattern

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Branch: refs/heads/main
Revision: 2ca4dc6
Author: mppf
Link: Warn for misleading 'new' pattern by mppf · Pull Request #20483 · chapel-lang/chapel · GitHub
Log Message:

Merge pull request #20483 from mppf/warn-misleading-new

Warn for misleading 'new' pattern

For

This PR adds a warning for patterns like

var x: borrowed C = new C(); // warn
x = new shared C(); // warn

including in variable initialization, split init, and assignment cases.

What happens in these patterns in that the result of the new expression
is stored into a temporary variable and then that is borrowed from. That
is because we have implicit conversions from owned/shared to borrowed. It
is unlikely that this pattern is useful (specifically when the RHS is a
new expression) and so this PR adds a warning for that case.

Reviewed by @daviditen - thanks!

  • full local testing

    Modified Files:
    A test/classes/errors/warn-misleading-new-unmanaged.chpl
    A test/classes/errors/warn-misleading-new-unmanaged.good
    A test/classes/errors/warn-misleading-new.chpl
    A test/classes/errors/warn-misleading-new.good
    M compiler/resolution/functionResolution.cpp
    M test/classes/delete-free/borrowed/coercions-to-init-borrowed.chpl
    M test/classes/delete-free/coercions-generic.chpl
    M test/classes/delete-free/coercions-shared.chpl
    M test/classes/delete-free/lifetimes/record-borrows.chpl
    M test/classes/delete-free/lifetimes/stecil-setup.chpl
    M test/classes/delete-free/tests-from-design-overview/new-myclass.chpl
    M test/classes/ferguson/generic-field/generic-field-unmanaged-borrowed.chpl
    M test/classes/initializers/generics/phase1/hasLoopGood.chpl
    M test/classes/lydia/staticMethodInheritance-whenField.chpl
    M test/classes/vass/ref-like-intents/inout-subclass.good
    M test/classes/vass/ref-like-intents/ref-subclass.good
    M test/classes/waynew/dyndis2.chpl
    M test/modules/diten/mutualuse2.chpl
    M test/trivial/jturner/iter_overload_simple.chpl
    M test/visibility/private/uses/accessSecondary.chpl
    M test/visibility/private/uses/accessSecondary.good
    M test/visibility/private/uses/pointOfInstantiation/methodOnType2.chpl
    M test/visibility/private/uses/pointOfInstantiation/methodOnType2.good

    Compare: Comparing d5d6eded2306...2ca4dc69286f · chapel-lang/chapel · GitHub