Improved warning for insensible comparisons.

Utilize knowledge of case class synthetic equals to rule out
some comparisons statically.  Closes SI-5426.

4 files changed, 28 insertions, 1 deletions

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)
+}