Merge pull request #14043 from dotty-staging/fix-12941

Don't retypecheck erroneous arguments when fixing function

Author: nicolasstucki

community-build/community-projects/protoquill

@@ -908,8 +908,9 @@ trait Applications extends Compatibility {
        *  part. Return an optional value to indicate success.
        */
       def tryWithImplicitOnQualifier(fun1: Tree, proto: FunProto)(using Context): Option[Tree] =
-        if (ctx.mode.is(Mode.SynthesizeExtMethodReceiver))
+        if ctx.mode.is(Mode.SynthesizeExtMethodReceiver) || proto.hasErrorArg then
           // Suppress insertion of apply or implicit conversion on extension method receiver
+          // or if argument is erroneous by itself.
           None
         else
           tryInsertImplicitOnQualifier(fun1, proto, ctx.typerState.ownedVars) flatMap { fun2 =>

compiler/src/dotty/tools/dotc/typer/Applications.scala

@@ -8,7 +8,7 @@ import Contexts._, Types._, Denotations._, Names._, StdNames._, NameOps._, Symbo
 import NameKinds.DepParamName
 import Trees._
 import Constants._
-import util.{Stats, SimpleIdentityMap}
+import util.{Stats, SimpleIdentityMap, SimpleIdentitySet}
 import Decorators._
 import Uniques._
 import config.Printers.typr
@@ -282,6 +282,9 @@ object ProtoTypes {
     /** A map in which typed arguments can be stored to be later integrated in `typedArgs`. */
     var typedArg: SimpleIdentityMap[untpd.Tree, Tree] = SimpleIdentityMap.empty
 
+    /** The argument that produced errors during typing */
+    var errorArgs: SimpleIdentitySet[untpd.Tree] = SimpleIdentitySet.empty
+
     /** The tupled or untupled version of this prototype, if it has been computed */
     var tupledDual: Type = NoType
 
@@ -341,6 +344,30 @@ object ProtoTypes {
       case _ => false
     }
 
+    /** Did an argument produce an error when typing? This means: an error was reported
+     *  and a tree got an error type. Errors of adaptation whree a tree has a good type
+     *  but that type does not conform to the expected type are not counted.
+     */
+    def hasErrorArg = !state.errorArgs.isEmpty
+
+    /** Does tree have embedded error trees that are not at the outside.
+     *  A nested tree t1 is "at the outside" relative to a tree t2 if
+     *    - t1 and t2 have the same span, or
+     *    - t2 is a ascription (t22: T) and t1 is at the outside of t22
+     *    - t2 is a closure (...) => t22 and t1 is at the outside of t22
+     */
+    def hasInnerErrors(t: Tree): Boolean = t match
+      case Typed(expr, tpe) => hasInnerErrors(expr)
+      case closureDef(mdef) => hasInnerErrors(mdef.rhs)
+      case _ =>
+        t.existsSubTree { t1 =>
+          if t1.typeOpt.isError && t1.span.toSynthetic != t.span.toSynthetic then
+            typr.println(i"error subtree $t1 of $t with ${t1.typeOpt}, spans = ${t1.span}, ${t.span}")
+            true
+          else
+            false
+        }
+
     private def cacheTypedArg(arg: untpd.Tree, typerFn: untpd.Tree => Tree, force: Boolean)(using Context): Tree = {
       var targ = state.typedArg(arg)
       if (targ == null)
@@ -357,8 +384,12 @@ object ProtoTypes {
             targ = arg.withType(WildcardType)
           case _ =>
             targ = typerFn(arg)
-            if (!ctx.reporter.hasUnreportedErrors)
+            if ctx.reporter.hasUnreportedErrors then
+              if hasInnerErrors(targ) then
+                state.errorArgs += arg
+            else
               state.typedArg = state.typedArg.updated(arg, targ)
+              state.errorArgs -= arg
         }
       targ
     }

compiler/src/dotty/tools/dotc/typer/ProtoTypes.scala

@@ -0,0 +1,16 @@
+-- Error: tests/neg-custom-args/deprecation/t3235-minimal.scala:3:21 ---------------------------------------------------
+3 |    assert(123456789.round == 123456789) // error
+  |           ^^^^^^^^^^^^^^^
+  |method round in class RichInt is deprecated since 2.11.0: this is an integer type; there is no reason to round it.  Perhaps you meant to call this on a floating-point value?
+-- Error: tests/neg-custom-args/deprecation/t3235-minimal.scala:4:16 ---------------------------------------------------
+4 |    assert(math.round(123456789) == 123456789) // error
+  |           ^^^^^^^^^^
+  |method round in package scala.math is deprecated since 2.11.0: This is an integer type; there is no reason to round it. Perhaps you meant to call this with a floating-point value?
+-- Error: tests/neg-custom-args/deprecation/t3235-minimal.scala:5:32 ---------------------------------------------------
+5 |    assert(1234567890123456789L.round == 1234567890123456789L) // error
+  |           ^^^^^^^^^^^^^^^^^^^^^^^^^^
+  |method round in class RichLong is deprecated since 2.11.0: this is an integer type; there is no reason to round it.  Perhaps you meant to call this on a floating-point value?
+-- Error: tests/neg-custom-args/deprecation/t3235-minimal.scala:6:16 ---------------------------------------------------
+6 |    assert(math.round(1234567890123456789L) == 1234567890123456789L) // error
+  |           ^^^^^^^^^^
+  |method round in package scala.math is deprecated since 2.11.0: This is an integer type; there is no reason to round it. Perhaps you meant to call this with a floating-point value?

tests/neg-custom-args/deprecation/t3235-minimal.check

@@ -0,0 +1,28 @@
+object A:
+  def myFun(op: String ?=> Unit) = ()
+
+@main def func: Unit =
+  A.myFun {
+    val res: String = summon[String]
+    println(ress)  // error
+  }
+
+class I:
+  def runSth: Int = 1
+
+abstract class A:
+  def myFun(op: I ?=> Unit) =
+    op(using I())
+    1
+
+class B extends A
+
+def assertEquals(x: String, y: Int, z: Int): Unit = ()
+
+@main def hello: Unit =
+
+  B().myFun {
+    val res = summon[I].runSth
+    assertEquals("", 1, res, "asd") // error
+    println("Hello!")
+  }

tests/neg/i12941.scala

@@ -0,0 +1,9 @@
+object Test {
+  val xs: List[Int] = ???
+
+  xs.lazyZip(xs).lazyZip(xs)
+    .map( (x: (Int, Int, Int)) => x match { case (x, y, z) => x + y + z })     // ok
+
+  xs.lazyZip(xs).lazyZip(xs)
+    .map( x => x match { case (x, y, z) => x + y + z })     // error
+}

tests/neg/zipped.scala

@@ -0,0 +1,20 @@
+import util.matching.Regex
+import util.matching.Regex.Match
+
+// Demonstrate what used to be a failure in specs2, before we refined
+// the scheme when not to typecheck a function argument again.
+object Test:
+
+  extension (s: String)
+
+    def replaceAll(pairs: (String, String)*): String =
+      pairs.foldLeft(s) { (res, cur) =>
+        res.replaceAll(cur._1, cur._2)
+      }
+
+    def replaceAll(exp: String, f: String => String): String =
+      new Regex(exp).replaceAllIn(s, (m: Match) => f(m.group(0).replace("\\", "\\\\")))
+
+    def replaceInsideTag(tag: String, p: (String, String)*): String =
+      s.replaceAll(tag, (s: String) => java.util.regex.Matcher.quoteReplacement(s.replaceAll(p*)))
+

tests/pos/specs2-failure.scala

@@ -26,9 +26,10 @@ object Test {
   xs.lazyZip(xs).lazyZip(xs)
     .map( (x: (Int, Int, Int)) => x match { case (x, y, z) => x + y + z })     // now also OK
 
-  // 5. If we leave out the parameter type, it now works as well.
-  xs.lazyZip(xs).lazyZip(xs)
-    .map( x => x match { case (x, y, z) => x + y + z })     // now also OK
+  // 5. But if that pone is deeper nested, it does not work since we don't retypecheck
+  //    arguments deeply.
+  //xs.lazyZip(xs).lazyZip(xs)
+  //  .map( x => x match { case (x, y, z) => x + y + z })     // now also OK
 
   // This means that the following works in Dotty 3.0 as well as 3.x
   for ((x, y, z) <- xs.lazyZip(xs).lazyZip(xs)) yield x + y + z