Merge pull request scala#1343 from namin/dynamic-sig

Fixes SI-6354: improved error messages for Dynamic signature mismatches.

Author: gkossakowski

src/compiler/scala/tools/nsc/typechecker/ContextErrors.scala

@@ -515,9 +515,16 @@ trait ContextErrors {
       def ApplyWithoutArgsError(tree: Tree, fun: Tree) =
         NormalTypeError(tree, fun.tpe+" does not take parameters")
 
+      // Dynamic
       def DynamicVarArgUnsupported(tree: Tree, name: String) =
         issueNormalTypeError(tree, name+ " does not support passing a vararg parameter")
 
+      def DynamicRewriteError(tree: Tree, err: AbsTypeError) = {
+        issueTypeError(PosAndMsgTypeError(err.errPos, err.errMsg +
+            s"\nerror after rewriting to $tree\npossible cause: maybe a wrong Dynamic method signature?"))
+        setError(tree)
+      }
+
       //checkClassType
       def TypeNotAStablePrefixError(tpt: Tree, pre: Type) = {
         issueNormalTypeError(tpt, "type "+pre+" is not a stable prefix")

src/compiler/scala/tools/nsc/typechecker/Typers.scala

@@ -3806,7 +3806,8 @@ trait Typers extends Modes with Adaptations with Tags {
           case AssignOrNamedArg(Ident(name), rhs) => gen.mkTuple(List(CODE.LIT(name.toString), rhs))
           case _ => gen.mkTuple(List(CODE.LIT(""), arg))
         }
-        typed(treeCopy.Apply(orig, fun, args map argToBinding), mode, pt)
+        val t = treeCopy.Apply(orig, fun, args map argToBinding)
+        wrapErrors(t, _.typed(t, mode, pt))
       }
 
       /** Translate selection that does not typecheck according to the normal rules into a selectDynamic/applyDynamic.
@@ -3874,6 +3875,13 @@ trait Typers extends Modes with Adaptations with Tags {
           atPos(qual.pos)(Apply(tappSel, List(Literal(Constant(name.decode)))))
         }
       }
+
+      def wrapErrors(tree: Tree, typeTree: Typer => Tree): Tree = {
+        silent(typeTree) match {
+          case SilentResultValue(r) => r
+          case SilentTypeError(err) => DynamicRewriteError(tree, err)
+	}
+      }
     }
 
     @inline final def deindentTyping() = context.typingIndentLevel -= 2
@@ -4067,7 +4075,8 @@ trait Typers extends Modes with Adaptations with Tags {
         }
         else if(dyna.isDynamicallyUpdatable(lhs1)) {
           val rhs1 = typed(rhs, EXPRmode | BYVALmode, WildcardType)
-          typed1(Apply(lhs1, List(rhs1)), mode, pt)
+          val t = Apply(lhs1, List(rhs1))
+          dyna.wrapErrors(t, _.typed1(t, mode, pt))
         }
         else fail()
       }
@@ -4535,7 +4544,9 @@ trait Typers extends Modes with Adaptations with Tags {
        *  @return     ...
        */
       def typedSelect(tree: Tree, qual: Tree, name: Name): Tree = {
-        def asDynamicCall = dyna.mkInvoke(context.tree, tree, qual, name) map (typed1(_, mode, pt))
+        def asDynamicCall = dyna.mkInvoke(context.tree, tree, qual, name) map { t =>
+          dyna.wrapErrors(t, (_.typed1(t, mode, pt)))
+        }
 
         val sym = tree.symbol orElse member(qual, name) orElse {
           // symbol not found? --> try to convert implicitly to a type that does have the required

test/files/neg/applydynamic_sip.check

@@ -7,4 +7,52 @@ applydynamic_sip.scala:8: error: applyDynamicNamed does not support passing a va
 applydynamic_sip.scala:9: error: applyDynamicNamed does not support passing a vararg parameter
   qual.sel(arg, arg2 = "a2", a2: _*)
        ^
-three errors found
+applydynamic_sip.scala:18: error: type mismatch;
+ found   : String("sel")
+ required: Int
+error after rewriting to Test.this.bad1.selectDynamic("sel")
+possible cause: maybe a wrong Dynamic method signature?
+  bad1.sel
+  ^
+applydynamic_sip.scala:19: error: type mismatch;
+ found   : String("sel")
+ required: Int
+error after rewriting to Test.this.bad1.applyDynamic("sel")
+possible cause: maybe a wrong Dynamic method signature?
+  bad1.sel(1)
+  ^
+applydynamic_sip.scala:20: error: type mismatch;
+ found   : String("sel")
+ required: Int
+error after rewriting to Test.this.bad1.applyDynamicNamed("sel")
+possible cause: maybe a wrong Dynamic method signature?
+  bad1.sel(a = 1)
+  ^
+applydynamic_sip.scala:21: error: type mismatch;
+ found   : String("sel")
+ required: Int
+error after rewriting to Test.this.bad1.updateDynamic("sel")
+possible cause: maybe a wrong Dynamic method signature?
+  bad1.sel = 1
+  ^
+applydynamic_sip.scala:29: error: Int does not take parameters
+error after rewriting to Test.this.bad2.selectDynamic("sel")
+possible cause: maybe a wrong Dynamic method signature?
+  bad2.sel
+  ^
+applydynamic_sip.scala:30: error: Int does not take parameters
+error after rewriting to Test.this.bad2.applyDynamic("sel")
+possible cause: maybe a wrong Dynamic method signature?
+  bad2.sel(1)
+  ^
+applydynamic_sip.scala:31: error: Int does not take parameters
+error after rewriting to Test.this.bad2.applyDynamicNamed("sel")
+possible cause: maybe a wrong Dynamic method signature?
+  bad2.sel(a = 1)
+  ^
+applydynamic_sip.scala:32: error: Int does not take parameters
+error after rewriting to Test.this.bad2.updateDynamic("sel")
+possible cause: maybe a wrong Dynamic method signature?
+  bad2.sel = 1
+  ^
+11 errors found

test/files/neg/applydynamic_sip.flags

@@ -0,0 +1 @@
+-language:dynamics

test/files/neg/applydynamic_sip.scala

@@ -7,4 +7,27 @@ object Test extends App {
   qual.sel(a, a2: _*)
   qual.sel(arg = a, a2: _*)
   qual.sel(arg, arg2 = "a2", a2: _*)
-}
+
+  val bad1 = new Dynamic {
+    def selectDynamic(n: Int) = n
+    def applyDynamic(n: Int) = n
+    def applyDynamicNamed(n: Int) = n
+    def updateDynamic(n: Int) = n
+
+  }
+  bad1.sel
+  bad1.sel(1)
+  bad1.sel(a = 1)
+  bad1.sel = 1
+
+  val bad2 = new Dynamic {
+    def selectDynamic = 1
+    def applyDynamic = 1
+    def applyDynamicNamed = 1
+    def updateDynamic = 1
+  }
+  bad2.sel
+  bad2.sel(1)
+  bad2.sel(a = 1)
+  bad2.sel = 1
+}