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Fix #9977: Refine unrelated types criterion #9980

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Merged
merged 1 commit into from
Oct 27, 2020
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Fix #9977: Refine unrelated types criterion #9980

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21 changes: 14 additions & 7 deletions compiler/src/dotty/tools/dotc/transform/TypeTestsCasts.scala
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Original file line number Diff line number Diff line change
@@ -1,4 +1,5 @@
package dotty.tools.dotc
package dotty.tools
package dotc
package transform

import core._
Expand Down Expand Up @@ -193,8 +194,11 @@ object TypeTestsCasts {
tree.fun.symbol == defn.Any_typeTest || // new scheme
expr.symbol.is(Case) // old scheme

def transformIsInstanceOf(expr: Tree, testType: Type, flagUnrelated: Boolean): Tree = {
def transformIsInstanceOf(
expr: Tree, testType: Type,
unboxedTestType: Type, flagUnrelated: Boolean): Tree = {
def testCls = effectiveClass(testType.widen)
def unboxedTestCls = effectiveClass(unboxedTestType.widen)

def unreachable(why: => String)(using Context): Boolean = {
if (flagUnrelated)
Expand Down Expand Up @@ -226,9 +230,10 @@ object TypeTestsCasts {
def check(foundCls: Symbol): Boolean =
if (!isCheckable(foundCls)) true
else if (!foundCls.derivesFrom(testCls)) {
val unrelated = !testCls.derivesFrom(foundCls) && (
testCls.is(Final) || !testCls.is(Trait) && !foundCls.is(Trait)
)
val unrelated =
!testCls.derivesFrom(foundCls)
&& !unboxedTestCls.derivesFrom(foundCls)
&& (testCls.is(Final) || !testCls.is(Trait) && !foundCls.is(Trait))
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This line seems to change semantics of the original code:

Suggested change
&& (testCls.is(Final) || !testCls.is(Trait) && !foundCls.is(Trait))
&& ((testCls.is(Final) || !testCls.is(Trait) && !foundCls.is(Trait)))

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I don't think so. All the suggestion does is double the pair of outer parens

if (foundCls.is(Final))
unreachable(i"$exprType is not a subclass of $testCls")
else if (unrelated)
Expand Down Expand Up @@ -265,7 +270,8 @@ object TypeTestsCasts {
case List(cls) if cls.isPrimitiveValueClass =>
constant(expr, Literal(Constant(foundClsSyms.head == testCls)))
case _ =>
transformIsInstanceOf(expr, defn.boxedType(testCls.typeRef), flagUnrelated)
transformIsInstanceOf(
expr, defn.boxedType(testCls.typeRef), testCls.typeRef, flagUnrelated)
else
derivedTree(expr, defn.Any_isInstanceOf, testType)
}
Expand Down Expand Up @@ -342,7 +348,8 @@ object TypeTestsCasts {
case AppliedType(tref: TypeRef, _) if tref.symbol == defn.PairClass =>
ref(defn.RuntimeTuple_isInstanceOfNonEmptyTuple).appliedTo(expr)
case _ =>
transformIsInstanceOf(expr, erasure(testType), flagUnrelated)
val erasedTestType = erasure(testType)
transformIsInstanceOf(expr, erasedTestType, erasedTestType, flagUnrelated)
}

if (sym.isTypeTest) {
Expand Down
1 change: 1 addition & 0 deletions tests/pos/i9977.scala
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Original file line number Diff line number Diff line change
@@ -0,0 +1 @@
val pf1: PartialFunction[AnyVal, Int] = { case n: Int => n }