8354090: Refactor import warning suppression in Check.java

[archiecobbs]

This is split off as a sub-task of JDK-8224228, which seeks to add @SuppressWarnings support for lexical features.

In JDK 9 and later, there is a special exception to the normal rules for deprecation and preview warnings, which is that these warnings are automatically suppressed for import statements. This is because an import statement is just a lexical shortcut, not an actual use of the symbol.

The current code in Check.java implements this by manipulating the current Lint instance directly, but this operation is incompatible upcoming changes to deferred lint handling. Instead, there can be an explicit flag for "import warning suppression" in Check.java to handle this. This will also make the code a bit clearer.

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Issue

• JDK-8354090: Refactor import warning suppression in Check.java (Sub-task - P4)

Reviewers

• Maurizio Cimadamore (@mcimadamore - Reviewer)

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[openjdk]

@archiecobbs This change now passes all automated pre-integration checks.

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8354090: Refactor import warning suppression in Check.java

Reviewed-by: mcimadamore

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At the time when this comment was updated there had been 749 new commits pushed to the master branch:

• 250eb74: 8353192: C2: Clean up x86 backend after 32-bit x86 removal
• 9ee5590: 8334046: Set different values for CompLevel_any and CompLevel_all
• 6df34c3: 8353174: Clean up thread register handling after 32-bit x86 removal
• ... and 746 more: https://git.openjdk.org/jdk/compare/ba28119642a7cfa850707a01ce8e589c3a80d416...master

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[archiecobbs]

We don't defer here because we want warnPreviewAPI() to use the current value of importSuppression, not some later value. But these warnings didn't really need to be deferred in the first place - because we can just use the current Lint instance, and in fact, that's what it was already doing. But a side effect of these changes is that the warnings checked in the PreviewAutoSuppress.java regression test get reordered.

[mlbridge]

Webrevs

• 00: Full (c4916439)

[mcimadamore]

This is fine. Another alternative that I'm mentioning for completeness would have been for attribImportType to set a flag on AttrContext (and then augment some of the methods in Check to accept an extra env parameter).

[mcimadamore]

Looks good

[archiecobbs]

/integrate

[openjdk]

Going to push as commit e50af6d.
Since your change was applied there have been 785 commits pushed to the master branch:

• c4c3edf: 8341402: BigDecimal's square root optimization
• 7e69b98: 8350441: ZGC: Overhaul Page Allocation
• 6c26670: 8324686: Remove redefinition of NULL for MSVC
• ... and 782 more: https://git.openjdk.org/jdk/compare/ba28119642a7cfa850707a01ce8e589c3a80d416...master

Your commit was automatically rebased without conflicts.

[openjdk]

@archiecobbs Pushed as commit e50af6d.

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[archiecobbs]

Thanks for the review!