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author | Paul Phillips <paulp@improving.org> | 2012-01-31 08:21:34 -0800 |
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committer | Paul Phillips <paulp@improving.org> | 2012-01-31 08:51:42 -0800 |
commit | 147e9eaf3814738f339b020e701a160ba2f68b60 (patch) | |
tree | e76a078289a446c69e5c6f952e71e75033553ae6 | |
parent | 263aa2ead1f599f48b218027eb9550745fef43f1 (diff) | |
download | scala-147e9eaf3814738f339b020e701a160ba2f68b60.tar.gz scala-147e9eaf3814738f339b020e701a160ba2f68b60.tar.bz2 scala-147e9eaf3814738f339b020e701a160ba2f68b60.zip |
Improved warning for insensible comparisons.
Utilize knowledge of case class synthetic equals to rule out
some comparisons statically. Closes SI-5426.
-rw-r--r-- | src/compiler/scala/tools/nsc/typechecker/RefChecks.scala | 11 | ||||
-rw-r--r-- | test/files/neg/checksensible.check | 5 | ||||
-rw-r--r-- | test/files/neg/t5426.check | 13 | ||||
-rw-r--r-- | test/files/neg/t5426.flags | 1 | ||||
-rw-r--r-- | test/files/neg/t5426.scala | 10 |
5 files changed, 35 insertions, 5 deletions
diff --git a/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala b/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala index a99d09173e..a6c2f75d5e 100644 --- a/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala +++ b/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala @@ -1034,10 +1034,10 @@ abstract class RefChecks extends InfoTransform with reflect.internal.transform.R /** Symbols which limit the warnings we can issue since they may be value types */ val isMaybeValue = Set(AnyClass, AnyRefClass, AnyValClass, ObjectClass, ComparableClass, JavaSerializableClass) - // Whether def equals(other: Any) is overridden - def isUsingDefaultEquals = { + // Whether def equals(other: Any) is overridden or synthetic + def isUsingWarnableEquals = { val m = receiver.info.member(nme.equals_) - (m == Object_equals) || (m == Any_equals) + (m == Object_equals) || (m == Any_equals) || (m.isSynthetic && m.owner.isCase) } // Whether this == or != is one of those defined in Any/AnyRef or an overload from elsewhere. def isUsingDefaultScalaOp = { @@ -1045,7 +1045,10 @@ abstract class RefChecks extends InfoTransform with reflect.internal.transform.R (s == Object_==) || (s == Object_!=) || (s == Any_==) || (s == Any_!=) } // Whether the operands+operator represent a warnable combo (assuming anyrefs) - def isWarnable = isReferenceOp || (isUsingDefaultEquals && isUsingDefaultScalaOp) + // Looking for comparisons performed with ==/!= in combination with either an + // equals method inherited from Object or a case class synthetic equals (for + // which we know the logic.) + def isWarnable = isReferenceOp || (isUsingDefaultScalaOp && isUsingWarnableEquals) def isEitherNullable = (NullClass.tpe <:< receiver.info) || (NullClass.tpe <:< actual.info) def isBoolean(s: Symbol) = unboxedValueClass(s) == BooleanClass def isUnit(s: Symbol) = unboxedValueClass(s) == UnitClass diff --git a/test/files/neg/checksensible.check b/test/files/neg/checksensible.check index 0881205bb4..d785179a56 100644 --- a/test/files/neg/checksensible.check +++ b/test/files/neg/checksensible.check @@ -28,6 +28,9 @@ checksensible.scala:27: error: comparing values of types Int and Unit using `==' checksensible.scala:29: error: comparing values of types Int and String using `==' will always yield false 1 == "abc" ^ +checksensible.scala:33: error: comparing values of types Some[Int] and Int using `==' will always yield false + Some(1) == 1 // as above + ^ checksensible.scala:38: error: comparing a fresh object using `==' will always yield false new AnyRef == 1 ^ @@ -94,4 +97,4 @@ checksensible.scala:84: error: comparing values of types EqEqRefTest.this.C3 and checksensible.scala:95: error: comparing values of types Unit and Int using `!=' will always yield true while ((c = in.read) != -1) ^ -32 errors found +33 errors found diff --git a/test/files/neg/t5426.check b/test/files/neg/t5426.check new file mode 100644 index 0000000000..d9e192d3f0 --- /dev/null +++ b/test/files/neg/t5426.check @@ -0,0 +1,13 @@ +t5426.scala:2: error: comparing values of types Some[Int] and Int using `==' will always yield false + def f1 = Some(5) == 5 + ^ +t5426.scala:3: error: comparing values of types Int and Some[Int] using `==' will always yield false + def f2 = 5 == Some(5) + ^ +t5426.scala:8: error: comparing values of types Int and Some[Int] using `==' will always yield false + (x1 == x2) + ^ +t5426.scala:9: error: comparing values of types Some[Int] and Int using `==' will always yield false + (x2 == x1) + ^ +four errors found diff --git a/test/files/neg/t5426.flags b/test/files/neg/t5426.flags new file mode 100644 index 0000000000..e8fb65d50c --- /dev/null +++ b/test/files/neg/t5426.flags @@ -0,0 +1 @@ +-Xfatal-warnings
\ No newline at end of file diff --git a/test/files/neg/t5426.scala b/test/files/neg/t5426.scala new file mode 100644 index 0000000000..f2fb5cc12c --- /dev/null +++ b/test/files/neg/t5426.scala @@ -0,0 +1,10 @@ +class A { + def f1 = Some(5) == 5 + def f2 = 5 == Some(5) + + val x1 = 5 + val x2 = Some(5) + + (x1 == x2) + (x2 == x1) +} |