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author | Paul Phillips <paulp@improving.org> | 2011-09-09 00:14:43 +0000 |
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committer | Paul Phillips <paulp@improving.org> | 2011-09-09 00:14:43 +0000 |
commit | ca15d245fd8624392756df5e79f893bea8ce53ef (patch) | |
tree | 044b7774a11c755700a8a2a8c33babce1083c6bb | |
parent | 65a785e17793e39a67a26ad30abe0a02edc5bf89 (diff) | |
download | scala-ca15d245fd8624392756df5e79f893bea8ce53ef.tar.gz scala-ca15d245fd8624392756df5e79f893bea8ce53ef.tar.bz2 scala-ca15d245fd8624392756df5e79f893bea8ce53ef.zip |
Brought back unrelated type comparison warning.
Figured out how to turn it on by default, even.
Closes SI-4979, no review.
-rw-r--r-- | src/compiler/scala/tools/nsc/typechecker/RefChecks.scala | 25 | ||||
-rw-r--r-- | test/files/neg/checksensible.check | 48 | ||||
-rw-r--r-- | test/files/neg/checksensible.scala | 5 |
3 files changed, 44 insertions, 34 deletions
diff --git a/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala b/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala index 0ff886dea6..1b28027bb1 100644 --- a/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala +++ b/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala @@ -966,10 +966,9 @@ abstract class RefChecks extends InfoTransform with reflect.internal.transform.R case _ => false } def underlyingClass(tp: Type): Symbol = { - var sym = tp.widen.typeSymbol - while (sym.isAbstractType) - sym = sym.info.bounds.hi.widen.typeSymbol - sym + val sym = tp.widen.typeSymbol + if (sym.isAbstractType) underlyingClass(sym.info.bounds.hi) + else sym } val actual = underlyingClass(args.head.tpe) val receiver = underlyingClass(qual.tpe) @@ -1009,8 +1008,11 @@ abstract class RefChecks extends InfoTransform with reflect.internal.transform.R def nonSensible(pre: String, alwaysEqual: Boolean) = nonSensibleWarning(pre+"values of types "+typesString, alwaysEqual) - def unrelatedTypes() = - unit.warning(pos, typesString + " are unrelated: should not compare equal") + def unrelatedTypes() = { + val msg = if (name == nme.EQ || name == nme.eq) + "never compare equal" else "always compare unequal" + unit.warning(pos, typesString + " are unrelated: they will most likely " + msg) + } if (nullCount == 2) nonSensible("", true) // null == null @@ -1047,13 +1049,14 @@ abstract class RefChecks extends InfoTransform with reflect.internal.transform.R nonSensible("", false) } } - // Warning on types without a parental relationship. Uncovers a lot of - // bugs, but not always right to warn. - if (false) { - if (nullCount == 0 && possibleNumericCount < 2 && !(receiver isSubClass actual) && !(actual isSubClass receiver)) + + if (nullCount == 0 && possibleNumericCount < 2) { + if (actual isSubClass receiver) () + else if (receiver isSubClass actual) () + // warn only if they have no common supertype below Object + else if (ObjectClass.tpe <:< global.lub(List(actual.tpe, receiver.tpe))) unrelatedTypes() } - case _ => } diff --git a/test/files/neg/checksensible.check b/test/files/neg/checksensible.check index 9977739196..085e00af2e 100644 --- a/test/files/neg/checksensible.check +++ b/test/files/neg/checksensible.check @@ -28,64 +28,70 @@ checksensible.scala:27: error: comparing values of types Int and Unit using `==' checksensible.scala:29: error: comparing values of types Int and java.lang.String using `==' will always yield false 1 == "abc" ^ -checksensible.scala:34: error: comparing a fresh object using `==' will always yield false +checksensible.scala:32: error: java.lang.String and Int are unrelated: they will most likely never compare equal + "abc" == 1 // warns because the lub of String and Int is Any + ^ +checksensible.scala:33: error: Some[Int] and Int are unrelated: they will most likely never compare equal + Some(1) == 1 // as above + ^ +checksensible.scala:35: error: comparing a fresh object using `==' will always yield false new AnyRef == 1 ^ -checksensible.scala:37: error: comparing values of types Int and java.lang.Boolean using `==' will always yield false +checksensible.scala:38: error: comparing values of types Int and java.lang.Boolean using `==' will always yield false 1 == (new java.lang.Boolean(true)) ^ -checksensible.scala:39: error: comparing values of types Int and Boolean using `!=' will always yield true +checksensible.scala:40: error: comparing values of types Int and Boolean using `!=' will always yield true 1 != true ^ -checksensible.scala:40: error: comparing values of types Unit and Boolean using `==' will always yield false +checksensible.scala:41: error: comparing values of types Unit and Boolean using `==' will always yield false () == true ^ -checksensible.scala:41: error: comparing values of types Unit and Unit using `==' will always yield true +checksensible.scala:42: error: comparing values of types Unit and Unit using `==' will always yield true () == () ^ -checksensible.scala:42: error: comparing values of types Unit and Unit using `==' will always yield true +checksensible.scala:43: error: comparing values of types Unit and Unit using `==' will always yield true () == println ^ -checksensible.scala:44: error: comparing values of types Int and Unit using `!=' will always yield true +checksensible.scala:45: error: comparing values of types Int and Unit using `!=' will always yield true (1 != println) ^ -checksensible.scala:45: error: comparing values of types Int and Symbol using `!=' will always yield true +checksensible.scala:46: error: comparing values of types Int and Symbol using `!=' will always yield true (1 != 'sym) ^ -checksensible.scala:51: error: comparing a fresh object using `==' will always yield false +checksensible.scala:52: error: comparing a fresh object using `==' will always yield false ((x: Int) => x + 1) == null ^ -checksensible.scala:52: error: comparing a fresh object using `==' will always yield false +checksensible.scala:53: error: comparing a fresh object using `==' will always yield false Bep == ((_: Int) + 1) ^ -checksensible.scala:54: error: comparing a fresh object using `==' will always yield false +checksensible.scala:55: error: comparing a fresh object using `==' will always yield false new Object == new Object ^ -checksensible.scala:55: error: comparing a fresh object using `==' will always yield false +checksensible.scala:56: error: comparing a fresh object using `==' will always yield false new Object == "abc" ^ -checksensible.scala:56: error: comparing a fresh object using `!=' will always yield true +checksensible.scala:57: error: comparing a fresh object using `!=' will always yield true new Exception() != new Exception() ^ -checksensible.scala:59: error: comparing values of types Int and Null using `==' will always yield false +checksensible.scala:60: error: comparing values of types Int and Null using `==' will always yield false if (foo.length == null) "plante" else "plante pas" ^ -checksensible.scala:64: error: comparing values of types Bip and Bop using `==' will always yield false +checksensible.scala:65: error: comparing values of types Bip and Bop using `==' will always yield false (x1 == x2) ^ -checksensible.scala:74: error: comparing values of types EqEqRefTest.this.C3 and EqEqRefTest.this.Z1 using `==' will always yield false +checksensible.scala:75: error: comparing values of types EqEqRefTest.this.C3 and EqEqRefTest.this.Z1 using `==' will always yield false c3 == z1 ^ -checksensible.scala:75: error: comparing values of types EqEqRefTest.this.Z1 and EqEqRefTest.this.C3 using `==' will always yield false +checksensible.scala:76: error: comparing values of types EqEqRefTest.this.Z1 and EqEqRefTest.this.C3 using `==' will always yield false z1 == c3 ^ -checksensible.scala:76: error: comparing values of types EqEqRefTest.this.Z1 and EqEqRefTest.this.C3 using `!=' will always yield true +checksensible.scala:77: error: comparing values of types EqEqRefTest.this.Z1 and EqEqRefTest.this.C3 using `!=' will always yield true z1 != c3 ^ -checksensible.scala:77: error: comparing values of types EqEqRefTest.this.C3 and java.lang.String using `!=' will always yield true +checksensible.scala:78: error: comparing values of types EqEqRefTest.this.C3 and java.lang.String using `!=' will always yield true c3 != "abc" ^ -checksensible.scala:88: error: comparing values of types Unit and Int using `!=' will always yield true +checksensible.scala:89: error: comparing values of types Unit and Int using `!=' will always yield true while ((c = in.read) != -1) ^ -30 errors found +32 errors found diff --git a/test/files/neg/checksensible.scala b/test/files/neg/checksensible.scala index 4872df4dfb..77b5a93f74 100644 --- a/test/files/neg/checksensible.scala +++ b/test/files/neg/checksensible.scala @@ -19,7 +19,7 @@ class RefEqTest { null eq new AnyRef } -// 11 warnings +// 13 warnings class EqEqValTest { var c = 0 @@ -29,7 +29,8 @@ class EqEqValTest { 1 == "abc" 1 == ("abc": Any) // doesn't warn because an Any may be a boxed Int 1 == (1: Any) // as above - "abc" == 1 // doesn't generally warn since String defines an equals method, but can chatty warn + "abc" == 1 // warns because the lub of String and Int is Any + Some(1) == 1 // as above new AnyRef == 1 1 == new AnyRef // doesn't warn because it could be... |