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nicolasstuckinicolasstucki
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Improve missing argument list error
Fixes #17123
1 parent 2dec682 commit b377c13

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8 files changed

+177
-18
lines changed

8 files changed

+177
-18
lines changed

‎compiler/src/dotty/tools/dotc/reporting/ErrorMessageID.scala‎

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -190,6 +190,7 @@ enum ErrorMessageID(val isActive: Boolean = true) extends java.lang.Enum[ErrorMe
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case InlineGivenShouldNotBeFunctionID // errorNumber 174
191191
case ValueDiscardingID // errorNumber 175
192192
case UnusedNonUnitValueID // errorNumber 176
193+
case MissingArgumentListID // errorNumber: 177
193194

194195
def errorNumber = ordinal - 1
195196

‎compiler/src/dotty/tools/dotc/reporting/messages.scala‎

Lines changed: 10 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -1470,6 +1470,16 @@ class MissingArgument(pname: Name, methString: String)(using Context)
14701470
else s"missing argument for parameter $pname of $methString"
14711471
def explain(using Context) = ""
14721472

1473+
class MissingArgumentList(method: String, sym: Symbol)(using Context)
1474+
extends TypeMsg(MissingArgumentListID) {
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def msg(using Context) =
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val symDcl = if sym.exists then "\n\n " + sym.showDcl else ""
1477+
i"missing argument list for $method$symDcl"
1478+
def explain(using Context) = {
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i"""Unapplied methods are only converted to functions when a function type is expected."""
1480+
}
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}
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14731483
class DoesNotConformToBound(tpe: Type, which: String, bound: Type)(using Context)
14741484
extends TypeMismatchMsg(
14751485
if which == "lower" then bound else tpe,

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

Lines changed: 17 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -41,12 +41,24 @@ object ErrorReporting {
4141
errorType(WrongNumberOfTypeArgs(fntpe, expectedArgs, actual), pos)
4242

4343
def missingArgs(tree: Tree, mt: Type)(using Context): Unit =
44+
def isCallableWithoutArgumentsLists(mt: Type): Boolean = mt match
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case pt: PolyType => isCallableWithoutArgumentsLists(pt.resType)
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case mt: MethodType if mt.isImplicitMethod => isCallableWithoutArgumentsLists(mt.resType)
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case mt: MethodType => false
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case _ => true
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def isCallableWithSingleEmptyArgumentList(mt: Type): Boolean =
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mt match
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case mt: MethodType if mt.paramNames.isEmpty => isCallableWithoutArgumentsLists(mt.resType)
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case mt: MethodType if mt.isImplicitMethod => isCallableWithSingleEmptyArgumentList(mt.resType)
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case pt: PolyType => isCallableWithSingleEmptyArgumentList(pt.resType)
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case _ => false
4455
val meth = err.exprStr(methPart(tree))
45-
mt match
46-
case mt: MethodType if mt.paramNames.isEmpty =>
47-
report.error(MissingEmptyArgumentList(meth), tree.srcPos)
48-
case _ =>
49-
report.error(em"missing arguments for $meth", tree.srcPos)
56+
val info = if tree.symbol.exists then tree.symbol.info else mt
57+
if isCallableWithSingleEmptyArgumentList(info) then
58+
report.error(MissingEmptyArgumentList(meth), tree.srcPos)
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else
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report.error(MissingArgumentList(meth, tree.symbol), tree.srcPos)
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5062

5163
def matchReductionAddendum(tps: Type*)(using Context): String =
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val collectMatchTrace = new TypeAccumulator[String]:

‎tests/neg/i16820.check‎

Lines changed: 18 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -1,18 +1,30 @@
1-
-- Error: tests/neg/i16820.scala:5:11 ----------------------------------------------------------------------------------
1+
-- [E177] Type Error: tests/neg/i16820.scala:5:11 ----------------------------------------------------------------------
22
5 | val x1 = f // error
33
| ^
4-
| missing arguments for method f in object Test
4+
| missing argument list for method f in object Test
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|
6+
| def f(xs: Int*): Int
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|
8+
| longer explanation available when compiling with `-explain`
59
-- [E100] Syntax Error: tests/neg/i16820.scala:6:11 --------------------------------------------------------------------
610
6 | val x2 = g // error
711
| ^
812
| method g in object Test must be called with () argument
913
|
1014
| longer explanation available when compiling with `-explain`
11-
-- Error: tests/neg/i16820.scala:7:40 ----------------------------------------------------------------------------------
15+
-- [E177] Type Error: tests/neg/i16820.scala:7:40 ----------------------------------------------------------------------
1216
7 | val x3 = java.nio.file.Paths.get(".").toRealPath // error
1317
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
14-
| missing arguments for method toRealPath in trait Path
15-
-- Error: tests/neg/i16820.scala:11:14 ---------------------------------------------------------------------------------
18+
| missing argument list for method toRealPath in trait Path
19+
|
20+
| def toRealPath(x$0: java.nio.file.LinkOption*): java.nio.file.Path
21+
|
22+
| longer explanation available when compiling with `-explain`
23+
-- [E177] Type Error: tests/neg/i16820.scala:11:14 ---------------------------------------------------------------------
1624
11 |def test = Foo(3) // error
1725
| ^^^^^^
18-
| missing arguments for method apply in object Foo
26+
| missing argument list for method apply in object Foo
27+
|
28+
| def apply(x: Int)(xs: String*): Foo
29+
|
30+
| longer explanation available when compiling with `-explain`

‎tests/neg/i17123.check‎

Lines changed: 86 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,86 @@
1+
-- [E100] Syntax Error: tests/neg/i17123.scala:7:2 ---------------------------------------------------------------------
2+
7 | m1 // error
3+
| ^^
4+
| method m1 in object ConfusingErrorMessage must be called with () argument
5+
|
6+
| longer explanation available when compiling with `-explain`
7+
-- [E177] Type Error: tests/neg/i17123.scala:9:2 -----------------------------------------------------------------------
8+
9 | m2 // error
9+
| ^^
10+
| missing argument list for method m2 in object ConfusingErrorMessage
11+
|
12+
| def m2()(): Unit
13+
|
14+
| longer explanation available when compiling with `-explain`
15+
-- [E177] Type Error: tests/neg/i17123.scala:10:4 ----------------------------------------------------------------------
16+
10 | m2() // error
17+
| ^^^^
18+
| missing argument list for method m2 in object ConfusingErrorMessage
19+
|
20+
| def m2()(): Unit
21+
|
22+
| longer explanation available when compiling with `-explain`
23+
-- [E177] Type Error: tests/neg/i17123.scala:11:2 ----------------------------------------------------------------------
24+
11 | m3 // error
25+
| ^^
26+
| missing argument list for method m3 in object ConfusingErrorMessage
27+
|
28+
| def m3()()(): Unit
29+
|
30+
| longer explanation available when compiling with `-explain`
31+
-- [E177] Type Error: tests/neg/i17123.scala:12:4 ----------------------------------------------------------------------
32+
12 | m3() // error
33+
| ^^^^
34+
| missing argument list for method m3 in object ConfusingErrorMessage
35+
|
36+
| def m3()()(): Unit
37+
|
38+
| longer explanation available when compiling with `-explain`
39+
-- [E177] Type Error: tests/neg/i17123.scala:13:6 ----------------------------------------------------------------------
40+
13 | m3()() // error
41+
| ^^^^^^
42+
| missing argument list for method m3 in object ConfusingErrorMessage
43+
|
44+
| def m3()()(): Unit
45+
|
46+
| longer explanation available when compiling with `-explain`
47+
-- [E177] Type Error: tests/neg/i17123.scala:15:2 ----------------------------------------------------------------------
48+
15 | f3 // error
49+
| ^^
50+
| missing argument list for method f3 in object ConfusingErrorMessage
51+
|
52+
| def f3()(i: Int)(): Unit
53+
|
54+
| longer explanation available when compiling with `-explain`
55+
-- [E177] Type Error: tests/neg/i17123.scala:16:2 ----------------------------------------------------------------------
56+
16 | f3() // error
57+
| ^^^^
58+
| missing argument list for method f3 in object ConfusingErrorMessage
59+
|
60+
| def f3()(i: Int)(): Unit
61+
|
62+
| longer explanation available when compiling with `-explain`
63+
-- [E177] Type Error: tests/neg/i17123.scala:17:6 ----------------------------------------------------------------------
64+
17 | f3()(2) // error
65+
| ^^^^^^^
66+
| missing argument list for method f3 in object ConfusingErrorMessage
67+
|
68+
| def f3()(i: Int)(): Unit
69+
|
70+
| longer explanation available when compiling with `-explain`
71+
-- [E177] Type Error: tests/neg/i17123.scala:19:2 ----------------------------------------------------------------------
72+
19 | i3 // error
73+
| ^^
74+
| missing argument list for method i3 in object ConfusingErrorMessage
75+
|
76+
| def i3()(using d: DummyImplicit)(): Unit
77+
|
78+
| longer explanation available when compiling with `-explain`
79+
-- [E177] Type Error: tests/neg/i17123.scala:20:2 ----------------------------------------------------------------------
80+
20 | i3() // error
81+
| ^^^^
82+
| missing argument list for method i3 in object ConfusingErrorMessage
83+
|
84+
| def i3()(using d: DummyImplicit)(): Unit
85+
|
86+
| longer explanation available when compiling with `-explain`

‎tests/neg/i17123.scala‎

Lines changed: 22 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,22 @@
1+
object ConfusingErrorMessage {
2+
def m1() = ()
3+
def m2()() = ()
4+
def m3()()() = ()
5+
def f3()(i: Int)() = ()
6+
def i3()(using d: DummyImplicit)() = ()
7+
m1 // error
8+
m1()
9+
m2 // error
10+
m2() // error
11+
m3 // error
12+
m3() // error
13+
m3()() // error
14+
m3()()()
15+
f3 // error
16+
f3() // error
17+
f3()(2) // error
18+
f3()(2)()
19+
i3 // error
20+
i3() // error
21+
i3()()
22+
}

‎tests/neg/i7816.scala‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1,4 +1,4 @@
11
object A {
22
def f()(>) = ??? // error
3-
import f.NonExistent // error
3+
import f.NonExistent
44
}

‎tests/neg/indent-colons.check‎

Lines changed: 22 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -47,15 +47,31 @@
4747
| Not found: file
4848
|
4949
| longer explanation available when compiling with `-explain`
50-
-- Error: tests/neg/indent-colons.scala:5:2 ----------------------------------------------------------------------------
50+
-- [E177] Type Error: tests/neg/indent-colons.scala:5:2 ----------------------------------------------------------------
5151
5 | tryEither: // error
5252
| ^^^^^^^^^
53-
| missing arguments for method tryEither
54-
-- Error: tests/neg/indent-colons.scala:11:2 ---------------------------------------------------------------------------
53+
| missing argument list for method tryEither
54+
|
55+
| def tryEither[T](x: T)(y: Int => T): T
56+
|
57+
| where: T is a type variable
58+
|
59+
| longer explanation available when compiling with `-explain`
60+
-- [E177] Type Error: tests/neg/indent-colons.scala:11:2 ---------------------------------------------------------------
5561
11 | tryEither: // error
5662
| ^^^^^^^^^
57-
| missing arguments for method tryEither
58-
-- Error: tests/neg/indent-colons.scala:18:2 ---------------------------------------------------------------------------
63+
| missing argument list for method tryEither
64+
|
65+
| def tryEither[T](x: T)(y: Int => T): T
66+
|
67+
| where: T is a type variable
68+
|
69+
| longer explanation available when compiling with `-explain`
70+
-- [E177] Type Error: tests/neg/indent-colons.scala:18:2 ---------------------------------------------------------------
5971
18 | Some(3).fold: // error
6072
| ^^^^^^^^^^^^
61-
| missing arguments for method fold in class Option
73+
| missing argument list for method fold in class Option
74+
|
75+
| final def fold[B](ifEmpty: => B)(f: A => B): B
76+
|
77+
| longer explanation available when compiling with `-explain`

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