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author | Paul Phillips <paulp@improving.org> | 2013-04-30 05:12:47 -0700 |
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committer | Paul Phillips <paulp@improving.org> | 2013-04-30 05:12:47 -0700 |
commit | 1fd4b7d2f435cf440f874ce99056bd1feeafa333 (patch) | |
tree | 9f81c799b6f413c2e09d6f7f80332dac351a19dd | |
parent | 3da1abe3a2e2752588ca8e2c7e889a321dae2037 (diff) | |
parent | d3aa9a7639c3c26b42a8faa9566d0d43a998b723 (diff) | |
download | scala-1fd4b7d2f435cf440f874ce99056bd1feeafa333.tar.gz scala-1fd4b7d2f435cf440f874ce99056bd1feeafa333.tar.bz2 scala-1fd4b7d2f435cf440f874ce99056bd1feeafa333.zip |
Merge pull request #2432 from retronym/ticket/delayed-init-ref
Warn on selection of vals from DelayedInit subclasses.
-rw-r--r-- | src/compiler/scala/tools/nsc/typechecker/RefChecks.scala | 11 | ||||
-rw-r--r-- | test/files/neg/delayed-init-ref.check | 10 | ||||
-rw-r--r-- | test/files/neg/delayed-init-ref.flags | 1 | ||||
-rw-r--r-- | test/files/neg/delayed-init-ref.scala | 42 |
4 files changed, 64 insertions, 0 deletions
diff --git a/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala b/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala index 7f8aeceeec..4933b8e0cb 100644 --- a/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala +++ b/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala @@ -1411,6 +1411,16 @@ abstract class RefChecks extends InfoTransform with scala.reflect.internal.trans } } + private def checkDelayedInitSelect(qual: Tree, sym: Symbol, pos: Position) = { + def isLikelyUninitialized = ( + (sym.owner isSubClass DelayedInitClass) + && !qual.tpe.isInstanceOf[ThisType] + && sym.accessedOrSelf.isVal + ) + if (settings.lint.value && isLikelyUninitialized) + unit.warning(pos, s"Selecting ${sym} from ${sym.owner}, which extends scala.DelayedInit, is likely to yield an uninitialized value") + } + private def lessAccessible(otherSym: Symbol, memberSym: Symbol): Boolean = ( (otherSym != NoSymbol) && !otherSym.isProtected @@ -1610,6 +1620,7 @@ abstract class RefChecks extends InfoTransform with scala.reflect.internal.trans if(settings.Xmigration.value != NoScalaVersion) checkMigration(sym, tree.pos) checkCompileTimeOnly(sym, tree.pos) + checkDelayedInitSelect(qual, sym, tree.pos) if (sym eq NoSymbol) { unit.warning(tree.pos, "Select node has NoSymbol! " + tree + " / " + tree.tpe) diff --git a/test/files/neg/delayed-init-ref.check b/test/files/neg/delayed-init-ref.check new file mode 100644 index 0000000000..42ccabed1b --- /dev/null +++ b/test/files/neg/delayed-init-ref.check @@ -0,0 +1,10 @@ +delayed-init-ref.scala:17: error: Selecting value vall from object O, which extends scala.DelayedInit, is likely to yield an uninitialized value + println(O.vall) // warn + ^ +delayed-init-ref.scala:19: error: Selecting value vall from object O, which extends scala.DelayedInit, is likely to yield an uninitialized value + println(vall) // warn + ^ +delayed-init-ref.scala:40: error: Selecting value foo from trait UserContext, which extends scala.DelayedInit, is likely to yield an uninitialized value + println({locally(()); this}.foo) // warn (spurious, but we can't discriminate) + ^ +three errors found diff --git a/test/files/neg/delayed-init-ref.flags b/test/files/neg/delayed-init-ref.flags new file mode 100644 index 0000000000..7949c2afa2 --- /dev/null +++ b/test/files/neg/delayed-init-ref.flags @@ -0,0 +1 @@ +-Xlint -Xfatal-warnings diff --git a/test/files/neg/delayed-init-ref.scala b/test/files/neg/delayed-init-ref.scala new file mode 100644 index 0000000000..f2aa804e28 --- /dev/null +++ b/test/files/neg/delayed-init-ref.scala @@ -0,0 +1,42 @@ +trait T { + val traitVal = "" +} + +object O extends App with T { + val vall = "" + lazy val lazyy = "" + def deff = "" + + println(vall) // no warn + new { + println(vall) // no warn + } +} + +object Client { + println(O.vall) // warn + import O.vall + println(vall) // warn + + println(O.lazyy) // no warn + println(O.deff) // no warn + println(O.traitVal) // no warn +} + +// Delayed init usage pattern from Specs2 +// See: https://groups.google.com/d/msg/scala-sips/wP6dL8nIAQs/ogjoPE-MSVAJ +trait Before extends DelayedInit { + def before() + override def delayedInit(x: => Unit): Unit = { before; x } +} +object Spec { + trait UserContext extends Before { + def before() = () + val foo = "foo" + } + new UserContext { + println(foo) // no warn + println(this.foo) // no warn + println({locally(()); this}.foo) // warn (spurious, but we can't discriminate) + } +} |