From 802771b403f6dd0f09e01e4e3e1189c70d4b7bec Mon Sep 17 00:00:00 2001 From: Paul Phillips Date: Wed, 8 Aug 2012 05:29:43 -0700 Subject: Better pattern matcher error message. For the common case when someone hasn't quite grokked the significance of lower case in a pattern match. I'd like to make all the unreachables errors, not warnings, but there may be a bug or two to clear out first. class A { def badEquals(x: Any, y: Any) = x match { case y => true case _ => false } } a.scala:3: warning: patterns after a variable pattern cannot match (SLS 8.1.1) If you intended to match against parameter y of method badEquals, you must use backticks, like: case `y` => case y => true ^ a.scala:4: warning: unreachable code due to variable pattern 'y' on line 3 case _ => false ^ two warnings found --- .../neg/macro-invalidsig-context-bounds.check | 8 +++--- .../neg/macro-invalidsig-implicit-params.check | 8 +++--- test/files/neg/newpat_unreachable.check | 27 ++++++++++++++++++++ test/files/neg/newpat_unreachable.flags | 1 + test/files/neg/newpat_unreachable.scala | 29 ++++++++++++++++++++++ test/files/neg/pat_unreachable.check | 8 +++++- test/files/neg/pat_unreachable.scala | 8 +++++- test/files/neg/t6048.check | 7 ++++-- 8 files changed, 84 insertions(+), 12 deletions(-) create mode 100644 test/files/neg/newpat_unreachable.check create mode 100644 test/files/neg/newpat_unreachable.flags create mode 100644 test/files/neg/newpat_unreachable.scala (limited to 'test/files') diff --git a/test/files/neg/macro-invalidsig-context-bounds.check b/test/files/neg/macro-invalidsig-context-bounds.check index 894eabc442..6c9482e537 100644 --- a/test/files/neg/macro-invalidsig-context-bounds.check +++ b/test/files/neg/macro-invalidsig-context-bounds.check @@ -1,4 +1,4 @@ -Impls_1.scala:5: error: macro implementations cannot have implicit parameters other than AbsTypeTag evidences - def foo[U: c.AbsTypeTag: Numeric](c: Ctx) = { - ^ -one error found +Impls_1.scala:5: error: macro implementations cannot have implicit parameters other than AbsTypeTag evidences + def foo[U: c.AbsTypeTag: Numeric](c: Ctx) = { + ^ +one error found diff --git a/test/files/neg/macro-invalidsig-implicit-params.check b/test/files/neg/macro-invalidsig-implicit-params.check index 029b8a4634..98b3167b7a 100644 --- a/test/files/neg/macro-invalidsig-implicit-params.check +++ b/test/files/neg/macro-invalidsig-implicit-params.check @@ -1,4 +1,4 @@ -Impls_Macros_1.scala:5: error: macro implementations cannot have implicit parameters other than AbsTypeTag evidences - def foo_targs[T, U: c.AbsTypeTag](c: Ctx)(implicit x: c.Expr[Int]) = { - ^ -one error found +Impls_Macros_1.scala:5: error: macro implementations cannot have implicit parameters other than AbsTypeTag evidences + def foo_targs[T, U: c.AbsTypeTag](c: Ctx)(implicit x: c.Expr[Int]) = { + ^ +one error found diff --git a/test/files/neg/newpat_unreachable.check b/test/files/neg/newpat_unreachable.check new file mode 100644 index 0000000000..08453cac19 --- /dev/null +++ b/test/files/neg/newpat_unreachable.check @@ -0,0 +1,27 @@ +newpat_unreachable.scala:6: error: patterns after a variable pattern cannot match (SLS 8.1.1) +If you intended to match against parameter b of method contrivedExample, you must use backticks, like: case `b` => + case b => println("matched b") + ^ +newpat_unreachable.scala:7: error: unreachable code due to variable pattern 'b' on line 6 +If you intended to match against parameter c of method contrivedExample, you must use backticks, like: case `c` => + case c => println("matched c") + ^ +newpat_unreachable.scala:8: error: unreachable code due to variable pattern 'b' on line 6 +If you intended to match against value d in class A, you must use backticks, like: case `d` => + case d => println("matched d") + ^ +newpat_unreachable.scala:9: error: unreachable code due to variable pattern 'b' on line 6 + case _ => println("matched neither") + ^ +newpat_unreachable.scala:22: error: patterns after a variable pattern cannot match (SLS 8.1.1) +If you intended to match against parameter b of method g, you must use backticks, like: case `b` => + case b => 1 + ^ +newpat_unreachable.scala:23: error: unreachable code due to variable pattern 'b' on line 22 +If you intended to match against parameter c of method h, you must use backticks, like: case `c` => + case c => 2 + ^ +newpat_unreachable.scala:24: error: unreachable code due to variable pattern 'b' on line 22 + case _ => 3 + ^ +7 errors found diff --git a/test/files/neg/newpat_unreachable.flags b/test/files/neg/newpat_unreachable.flags new file mode 100644 index 0000000000..85d8eb2ba2 --- /dev/null +++ b/test/files/neg/newpat_unreachable.flags @@ -0,0 +1 @@ +-Xfatal-warnings diff --git a/test/files/neg/newpat_unreachable.scala b/test/files/neg/newpat_unreachable.scala new file mode 100644 index 0000000000..c9cc85cec6 --- /dev/null +++ b/test/files/neg/newpat_unreachable.scala @@ -0,0 +1,29 @@ +object Test { + class A { + val d = 55 + + def contrivedExample[A, B, C](a: A, b: B, c: C): Unit = a match { + case b => println("matched b") + case c => println("matched c") + case d => println("matched d") + case _ => println("matched neither") + } + + def correctExample[A, B, C](a: A, b: B, c: C): Unit = a match { + case `b` => println("matched b") + case `c` => println("matched c") + case `d` => println("matched d") + case _ => println("matched neither") + } + + def f[A](a: A) = { + def g[B](b: B) = { + def h[C](c: C) = a match { + case b => 1 + case c => 2 + case _ => 3 + } + } + } + } +} diff --git a/test/files/neg/pat_unreachable.check b/test/files/neg/pat_unreachable.check index 4e1463d591..c5706b7fad 100644 --- a/test/files/neg/pat_unreachable.check +++ b/test/files/neg/pat_unreachable.check @@ -4,4 +4,10 @@ pat_unreachable.scala:5: error: unreachable code pat_unreachable.scala:9: error: unreachable code case Seq(x, y) => List(x, y) ^ -two errors found +pat_unreachable.scala:23: error: unreachable code + case c => println("matched c") + ^ +pat_unreachable.scala:24: error: unreachable code + case _ => println("matched neither") + ^ +four errors found diff --git a/test/files/neg/pat_unreachable.scala b/test/files/neg/pat_unreachable.scala index fc0fd41920..1f402e5212 100644 --- a/test/files/neg/pat_unreachable.scala +++ b/test/files/neg/pat_unreachable.scala @@ -8,7 +8,7 @@ object Test extends App { case Seq(x, y, _*) => x::y::Nil case Seq(x, y) => List(x, y) } - + def not_unreachable(xs:Seq[Char]) = xs match { case Seq(x, y, _*) => x::y::Nil case Seq(x) => List(x) @@ -17,4 +17,10 @@ object Test extends App { case Seq(x, y) => x::y::Nil case Seq(x, y, z, _*) => List(x,y) } + + def contrivedExample[A, B, C](a: A, b: B, c: C): Unit = a match { + case b => println("matched b") + case c => println("matched c") + case _ => println("matched neither") + } } diff --git a/test/files/neg/t6048.check b/test/files/neg/t6048.check index 051f41877e..5bdf2eca88 100644 --- a/test/files/neg/t6048.check +++ b/test/files/neg/t6048.check @@ -4,7 +4,10 @@ t6048.scala:3: error: unreachable code t6048.scala:8: error: unreachable code case _ if false => x // unreachable ^ -t6048.scala:14: error: unreachable code +t6048.scala:13: error: patterns after a variable pattern cannot match (SLS 8.1.1) + case _ => x + ^ +t6048.scala:14: error: unreachable code due to variable pattern on line 13 case 5 if true => x // unreachable ^ -three errors found +four errors found -- cgit v1.2.3