Line breaks ignored after infix operators.

[jonathanknowles]

Describe the bug Ormolu sometimes eats line breaks after infix operators, and replaces them with hanging indents.

To Reproduce Run ormolu on code similar to:

test :: Spec
test =
  describe "An example specification" $
    it "An example test case" $
      [ someRatherLongExpressionToServeAsAnIlluminatingExample,
        someRatherLongExpressionToServeAsAnIlluminatingExample,
        someRatherLongExpressionToServeAsAnIlluminatingExample,
        someRatherLongExpressionToServeAsAnIlluminatingExample
      ]
        `shouldWithSomeHandwavingBeVeryApproximatelyEqualTo`
          [ someRatherLongExpressionToServeAsAnIlluminatingExample,
            someRatherLongExpressionToServeAsAnIlluminatingExample,
            someRatherLongExpressionToServeAsAnIlluminatingExample,
            someRatherLongExpressionToServeAsAnIlluminatingExample
          ]

Notice the line break after the infix operator.

Expected behaviour The line break is preserved, and the subsequent expression is rendered to the right by one indent level.

Actual behaviour The line break is removed, and the subsequent expression is rendered with a hanging indent:

test :: Spec
test =
  describe "An example specification" $
    it "An example test case" $
      [ someRatherLongExpressionToServeAsAnIlluminatingExample,
        someRatherLongExpressionToServeAsAnIlluminatingExample,
        someRatherLongExpressionToServeAsAnIlluminatingExample,
        someRatherLongExpressionToServeAsAnIlluminatingExample
      ]
        `shouldWithSomeHandwavingBeVeryApproximatelyEqualTo` [ someRatherLongExpressionToServeAsAnIlluminatingExample,
                                                               someRatherLongExpressionToServeAsAnIlluminatingExample,
                                                               someRatherLongExpressionToServeAsAnIlluminatingExample,
                                                               someRatherLongExpressionToServeAsAnIlluminatingExample
                                                             ]

Environment

• OS name + version: Linux 5.4.0-135-generic #152-Ubuntu SMP Wed Nov 23 20:19:22 UTC 2022 x86_64 GNU/Linux
• Version of the code: ormolu 0.5.1.0 UNKNOWN UNKNOWN using ghc-lib-parser 9.4.3.20221104

Additional context

• We have a rather large code base (> 200,000 lines) that's formatted by hand, and we're interested in adopting an auto-formatter.
• Our team coding standard:
  • encourages an 80-column limit.
  • discourages hanging indents, preferring line breaks and indentation over vertical alignment.

We realise that ormolu does not provide support for a column limit, but we're wondering if we can get by with manually inserting line breaks where necessary.

Many thanks! Jonathan