diff options
| -rw-r--r-- | src/compiler/scala/tools/nsc/typechecker/Modes.scala | 14 | ||||
| -rw-r--r-- | src/compiler/scala/tools/nsc/typechecker/Typers.scala | 13 | ||||
| -rw-r--r-- | test/files/neg/checksensible.check | 4 | ||||
| -rw-r--r-- | test/files/neg/checksensible.scala | 2 |
4 files changed, 24 insertions, 9 deletions
diff --git a/src/compiler/scala/tools/nsc/typechecker/Modes.scala b/src/compiler/scala/tools/nsc/typechecker/Modes.scala index 3eff5ef024..5d827e0de2 100644 --- a/src/compiler/scala/tools/nsc/typechecker/Modes.scala +++ b/src/compiler/scala/tools/nsc/typechecker/Modes.scala @@ -86,6 +86,17 @@ trait Modes { */ final val TYPEPATmode = 0x10000 + /** STATmode is set when typing statements inside a block. + * + * This is useful only for skipping lub computations in + * such positions, when the expected type is known to be Unit. This + * saves time in pathological cases where lubs can take many seconds + * but in the end is discarded. + * + * TODO: Remove when lubs become types in their own right. + */ + final val STATmode = 0x20000 + final private val StickyModes = EXPRmode | PATTERNmode | TYPEmode | ALTmode final def onlyStickyModes(mode: Int) = @@ -128,7 +139,8 @@ trait Modes { (1 << 13) -> "ALTmode", (1 << 14) -> "HKmode", (1 << 15) -> "BYVALmode", - (1 << 16) -> "TYPEPATmode" + (1 << 16) -> "TYPEPATmode", + (1 << 17) -> "STATmode" ) def modeString(mode: Int): String = if (mode == 0) "NOmode" diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala index b0f6e44e88..f6d5f84107 100644 --- a/src/compiler/scala/tools/nsc/typechecker/Typers.scala +++ b/src/compiler/scala/tools/nsc/typechecker/Typers.scala @@ -1127,9 +1127,11 @@ trait Typers extends Modes with Adaptations with Taggings { if (inExprModeButNot(mode, FUNmode)) { pt.normalize match { case TypeRef(_, sym, _) => - // note: was if (pt.typeSymbol == UnitClass) but this leads to a potentially - // infinite expansion if pt is constant type () - if (sym == UnitClass && tree.tpe <:< AnyClass.tpe) { // (12) + // note: there was an additional '&& tree.tpe <:< AnyClass.tpe', claiming that + // it would save us from a potentially infinite expansion if pt is constant type () + // didn't seem to do any good, and the test would miss the fact that Object.tpe <:< AnyClass.tpe + // after erasure (triggered by try-catches added by cleanup for structural types) + if (sym == UnitClass) { // (12) if (settings.warnValueDiscard.value) context.unit.warning(tree.pos, "discarded non-Unit value") return typed(atPos(tree.pos)(Block(List(tree), Literal(Constant()))), mode, pt) @@ -2566,7 +2568,7 @@ trait Typers extends Modes with Adaptations with Taggings { } else newTyper(context.make(stat, exprOwner)) // XXX this creates a spurious dead code warning if an exception is thrown // in a constructor, even if it is the only thing in the constructor. - val result = checkDead(localTyper.typed(stat, EXPRmode | BYVALmode, WildcardType)) + val result = checkDead(localTyper.typed(stat, EXPRmode | BYVALmode | STATmode, WildcardType)) if (treeInfo.isSelfOrSuperConstrCall(result)) { context.inConstructorSuffix = true @@ -3861,6 +3863,7 @@ trait Typers extends Modes with Adaptations with Taggings { && thenTp =:= elseTp ) (thenp1.tpe, false) // use unpacked type // TODO: skolemize (lub of packed types) when that no longer crashes on files/pos/t4070b.scala + else if ((mode & STATmode) != 0) (definitions.UnitClass.tpe, true) else ptOrLub(List(thenp1.tpe, elsep1.tpe), pt) if (needAdapt) { //isNumericValueType(owntype)) { @@ -4744,7 +4747,7 @@ trait Typers extends Modes with Adaptations with Taggings { var catches1 = typedCases(catches, ThrowableClass.tpe, pt) val finalizer1 = if (finalizer.isEmpty) finalizer else typed(finalizer, UnitClass.tpe) - val (owntype, needAdapt) = ptOrLub(block1.tpe :: (catches1 map (_.tpe)), pt) + val (owntype, needAdapt) = if ((mode & STATmode) != 0) (definitions.UnitClass.tpe, true) else ptOrLub(block1.tpe :: (catches1 map (_.tpe)), pt) if (needAdapt) { block1 = adapt(block1, mode, owntype) catches1 = catches1 map (adaptCase(_, mode, owntype)) diff --git a/test/files/neg/checksensible.check b/test/files/neg/checksensible.check index 23af94180a..772d58322d 100644 --- a/test/files/neg/checksensible.check +++ b/test/files/neg/checksensible.check @@ -77,8 +77,8 @@ checksensible.scala:63: error: comparing a fresh object using `!=' will always y new Exception() != new Exception()
^
checksensible.scala:66: error: comparing values of types Int and Null using `==' will always yield false
- if (foo.length == null) "plante" else "plante pas"
- ^
+ val dummy = if (foo.length == null) "plante" else "plante pas"
+ ^
checksensible.scala:71: error: comparing values of types Bip and Bop using `==' will always yield false
(x1 == x2)
^
diff --git a/test/files/neg/checksensible.scala b/test/files/neg/checksensible.scala index 27ee908153..15a9b6d9b6 100644 --- a/test/files/neg/checksensible.scala +++ b/test/files/neg/checksensible.scala @@ -63,7 +63,7 @@ class EqEqRefTest { new Exception() != new Exception() val foo: Array[String] = Array("1","2","3") - if (foo.length == null) "plante" else "plante pas" + val dummy = if (foo.length == null) "plante" else "plante pas" // final classes with default equals val x1 = new Bip |