Merge pull request #2259 from Blaisorblade/issue/6123-try-3

SI-6123: -explaintypes should not explain errors which won't be reported, new attempt

9 files changed, 53 insertions, 6 deletions

diff --git a/src/compiler/scala/tools/nsc/typechecker/ContextErrors.scala b/src/compiler/scala/tools/nsc/typechecker/ContextErrors.scala
index 86ee7939c8..17e679b5dd 100644
--- a/src/compiler/scala/tools/nsc/typechecker/ContextErrors.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/ContextErrors.scala
@@ -172,8 +172,7 @@ trait ContextErrors {
         assert(!foundType.isErroneous && !req.isErroneous, (foundType, req))
 
         issueNormalTypeError(tree, withAddendum(tree.pos)(typeErrorMsg(foundType, req, infer.isPossiblyMissingArgs(foundType, req))) )
-        if (settings.explaintypes.value)
-          explainTypes(foundType, req)
+        infer.explainTypes(foundType, req)
       }
 
       def WithFilterError(tree: Tree, ex: AbsTypeError) = {
@@ -1273,11 +1272,12 @@ trait ContextErrors {
     // not exactly an error generator, but very related
     // and I dearly wanted to push it away from Macros.scala
     private def checkSubType(slot: String, rtpe: Type, atpe: Type) = {
-      val ok = if (macroDebugVerbose || settings.explaintypes.value) {
-        if (rtpe eq atpe) println(rtpe + " <: " + atpe + "?" + EOL + "true")
+      val ok = if (macroDebugVerbose) {
         withTypesExplained(rtpe <:< atpe)
       } else rtpe <:< atpe
       if (!ok) {
+        if (!macroDebugVerbose)
+          explainTypes(rtpe, atpe)
         compatibilityError("type mismatch for %s: %s does not conform to %s".format(slot, abbreviateCoreAliases(rtpe.toString), abbreviateCoreAliases(atpe.toString)))
       }
     }
diff --git a/src/compiler/scala/tools/nsc/typechecker/Infer.scala b/src/compiler/scala/tools/nsc/typechecker/Infer.scala
index 15ed784ae0..f1b80d9f1c 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Infer.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Infer.scala
@@ -313,8 +313,10 @@ trait Infer extends Checkable {
       */
     )
 
-    def explainTypes(tp1: Type, tp2: Type) =
-      withDisambiguation(List(), tp1, tp2)(global.explainTypes(tp1, tp2))
+    def explainTypes(tp1: Type, tp2: Type) = {
+      if (context.reportErrors)
+        withDisambiguation(List(), tp1, tp2)(global.explainTypes(tp1, tp2))
+    }
 
     /* -- Tests & Checks---------------------------------------------------- */
 
diff --git a/test/files/neg/abstract-explaintypes.check b/test/files/neg/abstract-explaintypes.check
new file mode 100644
index 0000000000..59c1ad2378
--- /dev/null
+++ b/test/files/neg/abstract-explaintypes.check
@@ -0,0 +1,11 @@
+abstract-explaintypes.scala:6: error: type mismatch;
+ found   : A
+ required: A.this.T
+  def foo2: T = bar().baz();
+                         ^
+abstract-explaintypes.scala:9: error: type mismatch;
+ found   : A
+ required: A.this.T
+  def foo5: T = baz().baz();
+                         ^
+two errors found
diff --git a/test/files/neg/abstract-explaintypes.flags b/test/files/neg/abstract-explaintypes.flags
new file mode 100644
index 0000000000..b36707c7cf
--- /dev/null
+++ b/test/files/neg/abstract-explaintypes.flags
@@ -0,0 +1 @@
+-explaintypes
diff --git a/test/files/neg/abstract-explaintypes.scala b/test/files/neg/abstract-explaintypes.scala
new file mode 100644
index 0000000000..f8ecae16fa
--- /dev/null
+++ b/test/files/neg/abstract-explaintypes.scala
@@ -0,0 +1,11 @@
+trait A {
+  type T <: A;
+  def baz(): A;
+  def bar(): T;
+  def foo1: A = bar().bar();
+  def foo2: T = bar().baz();
+  def foo3 = bar().baz();
+  def foo4: A = baz().bar();
+  def foo5: T = baz().baz();
+  def foo6 = baz().baz();
+}
diff --git a/test/files/pos/t6123-explaintypes-implicits.flags b/test/files/pos/t6123-explaintypes-implicits.flags
new file mode 100644
index 0000000000..b36707c7cf
--- /dev/null
+++ b/test/files/pos/t6123-explaintypes-implicits.flags
@@ -0,0 +1 @@
+-explaintypes
diff --git a/test/files/pos/t6123-explaintypes-implicits.scala b/test/files/pos/t6123-explaintypes-implicits.scala
new file mode 100644
index 0000000000..5242b443d5
--- /dev/null
+++ b/test/files/pos/t6123-explaintypes-implicits.scala
@@ -0,0 +1,13 @@
+object ImplicitBugReport {
+  trait Exp[+T]
+  trait CanBuildExp[-Elem, +To] extends (Exp[Elem] => To)
+  trait TraversableExp[T, ExpT <: Exp[T]] extends Exp[Traversable[T]]
+
+  implicit def canBuildExp[T]: CanBuildExp[T, Exp[T]] = ???
+  implicit def canBuildExpTrav[T, ExpT <: Exp[T]](implicit c: CanBuildExp[T, ExpT]): CanBuildExp[Traversable[T], TraversableExp[T, ExpT]] = ???
+  def toExpTempl[T, That](t: T)(implicit c: CanBuildExp[T, That]): That = ???
+
+  def testBug() {
+    val a1 = toExpTempl(Seq(1, 2, 3, 5))
+  }
+}
diff --git a/test/files/pos/t6123-explaintypes-macros.flags b/test/files/pos/t6123-explaintypes-macros.flags
new file mode 100644
index 0000000000..b36707c7cf
--- /dev/null
+++ b/test/files/pos/t6123-explaintypes-macros.flags
@@ -0,0 +1 @@
+-explaintypes
diff --git a/test/files/pos/t6123-explaintypes-macros.scala b/test/files/pos/t6123-explaintypes-macros.scala
new file mode 100644
index 0000000000..e650ad2038
--- /dev/null
+++ b/test/files/pos/t6123-explaintypes-macros.scala
@@ -0,0 +1,7 @@
+import scala.language.experimental.macros
+import scala.reflect.macros.Context
+
+object Macros {
+  def printf(format: String, params: Any*): Unit = macro printf_impl
+  def printf_impl(c: Context)(format: c.Expr[String], params: c.Expr[Any]*): c.Expr[Unit] = ???
+}