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Backport "Fix false positive in WUnused for renamed path-dependent imports" to LTS #20608

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Merged
merged 5 commits into from
Jun 20, 2024
Merged

Backport "Fix false positive in WUnused for renamed path-dependent imports" to LTS #20608

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ad96d1e
Fix false positive in WUnused for renamed path-dependent imports
szymon-rd Aug 28, 2023
cbfd4ae
Check if owner of symbol exists
szymon-rd Aug 29, 2023
e32c153
Revert "Check if owner of symbol exists"
szymon-rd Aug 29, 2023
03bb74d
Replace def with lazy val
szymon-rd Aug 29, 2023
06760a0
Replace lazy val with val
szymon-rd Aug 31, 2023
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6 changes: 4 additions & 2 deletions compiler/src/dotty/tools/dotc/transform/CheckUnused.scala
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Original file line number Diff line number Diff line change
Expand Up @@ -661,8 +661,10 @@ object CheckUnused:
val simpleSelections = qual.tpe.member(sym.name).alternatives
val typeSelections = sels.flatMap(n => qual.tpe.member(n.name.toTypeName).alternatives)
val termSelections = sels.flatMap(n => qual.tpe.member(n.name.toTermName).alternatives)
val sameTermPath = qual.isTerm && sym.exists && sym.owner.isType && qual.tpe.typeSymbol == sym.owner.asType
val selectionsToDealias = typeSelections ::: termSelections
val qualHasSymbol = simpleSelections.map(_.symbol).contains(sym) || (simpleSelections ::: selectionsToDealias).map(_.symbol).map(dealias).contains(dealiasedSym)
val renamedSelection = if sameTermPath then sels.find(sel => sel.imported.name == sym.name) else None
val qualHasSymbol = simpleSelections.map(_.symbol).contains(sym) || (simpleSelections ::: selectionsToDealias).map(_.symbol).map(dealias).contains(dealiasedSym) || renamedSelection.isDefined
def selector = sels.find(sel => (sel.name.toTermName == sym.name || sel.name.toTypeName == sym.name) && symName.map(n => n.toTermName == sel.rename).getOrElse(true))
def dealiasedSelector = if(isDerived) sels.flatMap(sel => selectionsToDealias.map(m => (sel, m.symbol))).collect {
case (sel, sym) if dealias(sym) == dealiasedSym => sel
Expand All @@ -672,7 +674,7 @@ object CheckUnused:
else None
def wildcard = sels.find(sel => sel.isWildcard && ((sym.is(Given) == sel.isGiven && sel.bound.isEmpty) || sym.is(Implicit)))
if qualHasSymbol && (!isAccessible || sym.isRenamedSymbol(symName)) && sym.exists then
selector.orElse(dealiasedSelector).orElse(givenSelector).orElse(wildcard) // selector with name or wildcard (or given)
selector.orElse(dealiasedSelector).orElse(givenSelector).orElse(wildcard).orElse(renamedSelection) // selector with name or wildcard (or given)
else
None

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10 changes: 10 additions & 0 deletions tests/pos-special/fatal-warnings/i18366.scala
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@@ -0,0 +1,10 @@
// scalac: -Wunused:all

trait Builder {
def foo(): Unit
}

def repro =
val builder: Builder = ???
import builder.{foo => bar}
bar()