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authorAdriaan Moors <adriaan@lightbend.com>2017-04-11 16:57:16 -0700
committerAdriaan Moors <adriaan@lightbend.com>2017-04-12 07:51:18 -0700
commit747e22322330a762dd54037ccc1cb3608c6691bd (patch)
tree1f18742955bbdc6914c23c739e65f11a738895a3
parent12c240d69b6958d2c8f03a7728c097dd215011cd (diff)
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Actually retract clashing synthetic apply/unapply
The completer set the IS_ERROR flag and I assumed the typer dropped a synthetic tree with a symbol with that flag, because the tree was not shown in -Xprint output. It turns out, as explained by lrytz, that the mechanism was fragile because it relied on the order in which completers are run. We now cover both the case that: - the completer was run (and the `IS_ERROR` flag was set) before `addSynthetics` in `typedStat` iterates over the scope (since the symbol is already unlinked, the tree is not added, irrespective of its flags). For this case, we also remove the symbol from the synthetics in its unit. - the completer is triggered during the iteration in `addSynthetics`, which needs the check for the `IS_ERROR` flag during the iteration. Thankfully, the community build caught my mistake, and lrytz provided a good analysis and review. Fix scala/bug#10261
-rw-r--r--src/compiler/scala/tools/nsc/typechecker/Namers.scala10
-rw-r--r--src/compiler/scala/tools/nsc/typechecker/Typers.scala4
-rw-r--r--test/files/run/t10261/Companion_1.scala4
-rw-r--r--test/files/run/t10261/Test_2.scala14
4 files changed, 31 insertions, 1 deletions
diff --git a/src/compiler/scala/tools/nsc/typechecker/Namers.scala b/src/compiler/scala/tools/nsc/typechecker/Namers.scala
index bbb9d33140..f69d1d5254 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Namers.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Namers.scala
@@ -664,7 +664,17 @@ trait Namers extends MethodSynthesis {
if (suppress) {
sym setInfo ErrorType
+
+ // There are two ways in which we exclude the symbol from being added in typedStats::addSynthetics,
+ // because we don't know when the completer runs with respect to this loop in addSynthetics
+ // for (sym <- scope)
+ // for (tree <- context.unit.synthetics.get(sym) if shouldAdd(sym)) {
+ // if (!sym.initialize.hasFlag(IS_ERROR))
+ // newStats += typedStat(tree)
+ // If we're already in the loop, set the IS_ERROR flag and trigger the condition `sym.initialize.hasFlag(IS_ERROR)`
sym setFlag IS_ERROR
+ // Or, if we are not yet in the addSynthetics loop, we can just retract our symbol from the synthetics for this unit.
+ companionContext.unit.synthetics -= sym
// Don't unlink in an error situation to generate less confusing error messages.
// Ideally, our error reporting would distinguish overloaded from recursive user-defined apply methods without signature,
diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
index cd4a883a33..69bf5fdef7 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Typers.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
@@ -3168,7 +3168,9 @@ trait Typers extends Adaptations with Tags with TypersTracking with PatternTyper
for (sym <- scope)
// OPT: shouldAdd is usually true. Call it here, rather than in the outer loop
for (tree <- context.unit.synthetics.get(sym) if shouldAdd(sym)) {
- newStats += typedStat(tree) // might add even more synthetics to the scope
+ // if the completer set the IS_ERROR flag, retract the stat (currently only used by applyUnapplyMethodCompleter)
+ if (!sym.initialize.hasFlag(IS_ERROR))
+ newStats += typedStat(tree) // might add even more synthetics to the scope
context.unit.synthetics -= sym
}
// the type completer of a synthetic might add more synthetics. example: if the
diff --git a/test/files/run/t10261/Companion_1.scala b/test/files/run/t10261/Companion_1.scala
new file mode 100644
index 0000000000..9b8e2c73b2
--- /dev/null
+++ b/test/files/run/t10261/Companion_1.scala
@@ -0,0 +1,4 @@
+trait Companion[T] {
+ def parse(value: String): Option[T]
+ def apply(value: String): T = parse(value).get
+}
diff --git a/test/files/run/t10261/Test_2.scala b/test/files/run/t10261/Test_2.scala
new file mode 100644
index 0000000000..d7d9fe9a0e
--- /dev/null
+++ b/test/files/run/t10261/Test_2.scala
@@ -0,0 +1,14 @@
+import scala.util.Try
+
+object C extends Companion[C] {
+ def parse(v: String) = if (v.nonEmpty) Some(new C(v)) else None
+}
+
+case class C(value: String)
+
+object Test {
+ def main(args: Array[String]): Unit = {
+ assert(Try{C("")}.isFailure, "Empty value should fail to parse") // check that parse is used to validate input
+ assert(C("a").value == "a", "Unexpected value")
+ }
+}