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Use other tree for actual symbol of Assign
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+277
-30
lines changed

13 files changed

+277
-30
lines changed

‎compiler/src/dotty/tools/dotc/ast/Trees.scala‎

Lines changed: 3 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -1821,16 +1821,15 @@ object Trees {
18211821
}
18221822
}
18231823

1824-
def rename(tree: NameTree, newName: Name)(using Context): tree.ThisTree[T] = {
1825-
tree match {
1824+
def rename(tree: NameTree, newName: Name)(using Context): tree.ThisTree[T] =
1825+
tree.match
18261826
case tree: Ident => cpy.Ident(tree)(newName)
18271827
case tree: Select => cpy.Select(tree)(tree.qualifier, newName)
18281828
case tree: Bind => cpy.Bind(tree)(newName, tree.body)
18291829
case tree: ValDef => cpy.ValDef(tree)(name = newName.asTermName)
18301830
case tree: DefDef => cpy.DefDef(tree)(name = newName.asTermName)
18311831
case tree: TypeDef => cpy.TypeDef(tree)(name = newName.asTypeName)
1832-
}
1833-
}.asInstanceOf[tree.ThisTree[T]]
1832+
.asInstanceOf[tree.ThisTree[T]]
18341833

18351834
object TypeDefs:
18361835
def unapply(xs: List[Tree]): Option[List[TypeDef]] = xs match

‎compiler/src/dotty/tools/dotc/printing/Formatting.scala‎

Lines changed: 3 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@ import core.*
88
import Texts.*, Types.*, Flags.*, Symbols.*, Contexts.*
99
import Decorators.*
1010
import reporting.Message
11-
import util.{DiffUtil, SimpleIdentitySet}
11+
import util.{Chars, DiffUtil, SimpleIdentitySet}
1212
import Highlighting.*
1313

1414
object Formatting {
@@ -169,7 +169,8 @@ object Formatting {
169169
}
170170

171171
def assemble(args: Seq[Shown])(using Context): String = {
172-
def isLineBreak(c: Char) = c == '\n' || c == '\f' // compatible with StringLike#isLineBreak
172+
// compatible with CharArrayReader (not StringOps)
173+
inline def isLineBreak(c: Char) = c == Chars.LF || c == Chars.FF
173174
def stripTrailingPart(s: String) = {
174175
val (pre, post) = s.span(c => !isLineBreak(c))
175176
pre ++ post.stripMargin

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

Lines changed: 16 additions & 10 deletions
Original file line numberDiff line numberDiff line change
@@ -1526,18 +1526,24 @@ class AmbiguousExtensionMethod(tree: untpd.Tree, expansion1: tpd.Tree, expansion
15261526
|are possible expansions of $tree"""
15271527
def explain(using Context) = ""
15281528

1529-
class ReassignmentToVal(name: Name)(using Context)
1530-
extends TypeMsg(ReassignmentToValID) {
1531-
def msg(using Context) = i"""Reassignment to val $name"""
1532-
def explain(using Context) =
1533-
i"""|You can not assign a new value to $name as values can't be changed.
1534-
|Keep in mind that every statement has a value, so you may e.g. use
1535-
| ${hl("val")} $name ${hl("= if (condition) 2 else 5")}
1536-
|In case you need a reassignable name, you can declare it as
1537-
|variable
1529+
class ReassignmentToVal(sym: Symbol, usage: Name)(using Context) extends TypeMsg(ReassignmentToValID):
1530+
private def name = if sym.exists then sym.name else usage
1531+
private def addendum = if !sym.exists || !sym.owner.isClass then "" else
1532+
i"""|
1533+
|Also, assignment syntax can be used if there is a corresponding setter:
1534+
| ${hl("def")} ${name}${hl("_=(x: Int): Unit = _v = x")}
1535+
|"""
1536+
def msg(using Context) =
1537+
if sym.exists then i"""Assignment to $sym"""
1538+
else i"""Bad assignment to $usage"""
1539+
def explain(using Context) =
1540+
i"""|Members defined using `val` or `def` can't be assigned to.
1541+
|If you need to change the value of $name, use `var` instead:
15381542
| ${hl("var")} $name ${hl("=")} ...
1543+
|However, it's more common to initialize a variable just once
1544+
|with a complex expression or even a block with many statements:
1545+
| ${hl("val")} $name ${hl("= if (condition) 1 else -1")}$addendum
15391546
|"""
1540-
}
15411547

15421548
class TypeDoesNotTakeParameters(tpe: Type, params: List[untpd.Tree])(using Context)
15431549
extends TypeMsg(TypeDoesNotTakeParametersID) {

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

Lines changed: 5 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -128,18 +128,17 @@ trait Dynamic {
128128
/** Translate selection that does not typecheck according to the normal rules into a updateDynamic.
129129
* foo.bar = baz ~~> foo.updateDynamic(bar)(baz)
130130
*/
131-
def typedDynamicAssign(tree: untpd.Assign, pt: Type)(using Context): Tree = {
131+
def typedDynamicAssign(tree: untpd.Assign, pt: Type)(using Context): Tree =
132132
def typedDynamicAssign(qual: untpd.Tree, name: Name, selSpan: Span, targs: List[untpd.Tree]): Tree =
133133
typedApply(untpd.Apply(coreDynamic(qual, nme.updateDynamic, name, selSpan, targs), tree.rhs), pt)
134-
tree.lhs match {
134+
tree.lhs match
135135
case sel @ Select(qual, name) if !isDynamicMethod(name) =>
136136
typedDynamicAssign(qual, name, sel.span, Nil)
137137
case TypeApply(sel @ Select(qual, name), targs) if !isDynamicMethod(name) =>
138138
typedDynamicAssign(qual, name, sel.span, targs)
139-
case _ =>
140-
errorTree(tree, ReassignmentToVal(tree.lhs.symbol.name))
141-
}
142-
}
139+
case lhs =>
140+
val name = lhs match { case nt: NameTree => nt.name case _ => nme.NO_NAME }
141+
errorTree(tree, ReassignmentToVal(lhs.symbol, name))
143142

144143
private def coreDynamic(qual: untpd.Tree, dynName: Name, name: Name, selSpan: Span, targs: List[untpd.Tree])(using Context): untpd.Apply = {
145144
val select = untpd.Select(qual, dynName).withSpan(selSpan)

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

Lines changed: 9 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -1373,9 +1373,11 @@ class Typer(@constructorOnly nestingLevel: Int = 0) extends Namer
13731373

13741374
def typedAssign(tree: untpd.Assign, pt: Type)(using Context): Tree =
13751375
tree.lhs match {
1376-
case lhs @ Apply(fn, args) =>
1377-
typed(untpd.Apply(untpd.Select(fn, nme.update), args :+ tree.rhs), pt)
1378-
case untpd.TypedSplice(Apply(MaybePoly(Select(fn, app), targs), args)) if app == nme.apply =>
1376+
case Apply(fn, args) =>
1377+
val appliedUpdate =
1378+
untpd.Apply(untpd.Select(fn, nme.update), args :+ tree.rhs)
1379+
typed(appliedUpdate, pt)
1380+
case untpd.TypedSplice(Apply(MaybePoly(Select(fn, nme.apply), targs), args)) =>
13791381
val rawUpdate: untpd.Tree = untpd.Select(untpd.TypedSplice(fn), nme.update)
13801382
val wrappedUpdate =
13811383
if (targs.isEmpty) rawUpdate
@@ -1389,7 +1391,8 @@ class Typer(@constructorOnly nestingLevel: Int = 0) extends Namer
13891391
def lhs1 = adapt(lhsCore, LhsProto, locked)
13901392

13911393
def reassignmentToVal =
1392-
report.error(ReassignmentToVal(lhsCore.symbol.name), tree.srcPos)
1394+
val name = lhs match { case nt: NameTree => nt.name case _ => nme.NO_NAME }
1395+
report.error(ReassignmentToVal(lhs1.symbol, name), tree.srcPos)
13931396
cpy.Assign(tree)(lhsCore, typed(tree.rhs, lhs1.tpe.widen)).withType(defn.UnitType)
13941397

13951398
def canAssign(sym: Symbol) =
@@ -1478,8 +1481,9 @@ class Typer(@constructorOnly nestingLevel: Int = 0) extends Namer
14781481
typedDynamicAssign(tree, pt)
14791482
case tpe =>
14801483
reassignmentToVal
1481-
}
1484+
}
14821485
}
1486+
end typedAssign
14831487

14841488
def typedBlockStats(stats: List[untpd.Tree])(using Context): (List[tpd.Tree], Context) =
14851489
index(stats)

‎tests/neg/assignments.check‎

Lines changed: 12 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,12 @@
1+
-- [E052] Type Error: tests/neg/assignments.scala:16:8 -----------------------------------------------------------------
2+
16 | x_= = 2 // error should give missing arguments
3+
| ^^^^^^^
4+
| Bad assignment to x_=
5+
|
6+
| longer explanation available when compiling with `-explain`
7+
-- [E083] Type Error: tests/neg/assignments.scala:20:9 -----------------------------------------------------------------
8+
20 | import c._ // error should give: prefix is not stable
9+
| ^
10+
| (assignments.c : assignments.C) is not a valid import prefix, since it is not an immutable path
11+
|
12+
| longer explanation available when compiling with `-explain`

‎tests/neg/i11561.check‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -11,6 +11,6 @@
1111
-- [E052] Type Error: tests/neg/i11561.scala:3:30 ----------------------------------------------------------------------
1212
3 | val updateText2 = copy(text = (_: String)) // error
1313
| ^^^^^^^^^^^^^^^^^^
14-
| Reassignment to val text
14+
| Assignment to value text
1515
|
1616
| longer explanation available when compiling with `-explain`

‎tests/neg/i16655.check‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1,6 +1,6 @@
11
-- [E052] Type Error: tests/neg/i16655.scala:3:4 -----------------------------------------------------------------------
22
3 | x = 5 // error
33
| ^^^^^
4-
| Reassignment to val x
4+
| Assignment to value x
55
|
66
| longer explanation available when compiling with `-explain`

‎tests/neg/i20338c.check‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1,6 +1,6 @@
11
-- [E052] Type Error: tests/neg/i20338c.scala:9:6 ----------------------------------------------------------------------
22
9 | f.x = 42 // error
33
| ^^^^^^^^
4-
| Reassignment to val x
4+
| Assignment to value x
55
|
66
| longer explanation available when compiling with `-explain`

‎tests/neg/i22671.check‎

Lines changed: 55 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,55 @@
1+
-- [E007] Type Mismatch Error: tests/neg/i22671.scala:41:22 ------------------------------------------------------------
2+
41 | names_times(fields(0)) += fields(1).toLong // error
3+
| ^^^^^^^^^
4+
| Found: Char
5+
| Required: String
6+
|
7+
| longer explanation available when compiling with `-explain`
8+
-- [E008] Not Found Error: tests/neg/i22671.scala:45:6 -----------------------------------------------------------------
9+
45 | x() += "42" // error
10+
| ^^^^^^
11+
| value += is not a member of Int - did you mean Int.!=? or perhaps Int.<=?
12+
-- [E052] Type Error: tests/neg/i22671.scala:9:6 -----------------------------------------------------------------------
13+
9 | X.w = 27 // error
14+
| ^^^^^^^^
15+
| Assignment to value w
16+
|
17+
| longer explanation available when compiling with `-explain`
18+
-- [E052] Type Error: tests/neg/i22671.scala:12:6 ----------------------------------------------------------------------
19+
12 | X.x = 27 // error
20+
| ^^^^^^^^
21+
| Assignment to method x
22+
|
23+
| longer explanation available when compiling with `-explain`
24+
-- [E052] Type Error: tests/neg/i22671.scala:16:4 ----------------------------------------------------------------------
25+
16 | x = 27 // error
26+
| ^^^^^^
27+
| Assignment to method x
28+
|
29+
| longer explanation available when compiling with `-explain`
30+
-- [E052] Type Error: tests/neg/i22671.scala:20:4 ----------------------------------------------------------------------
31+
20 | y = 27 // error
32+
| ^^^^^^
33+
| Assignment to method x
34+
|
35+
| longer explanation available when compiling with `-explain`
36+
-- [E052] Type Error: tests/neg/i22671.scala:24:4 ----------------------------------------------------------------------
37+
24 | y = 27 // error
38+
| ^^^^^^
39+
| Assignment to value z
40+
|
41+
| longer explanation available when compiling with `-explain`
42+
-- [E052] Type Error: tests/neg/i22671.scala:28:4 ----------------------------------------------------------------------
43+
28 | x = 27 // error
44+
| ^^^^^^
45+
| Assignment to value x
46+
|
47+
| longer explanation available when compiling with `-explain`
48+
-- [E008] Not Found Error: tests/neg/i22671.scala:31:6 -----------------------------------------------------------------
49+
31 | X.x += 27 // error
50+
| ^^^^^^
51+
| value += is not a member of Int - did you mean Int.!=? or perhaps Int.<=?
52+
-- [E008] Not Found Error: tests/neg/i22671.scala:32:4 -----------------------------------------------------------------
53+
32 | 1 += 1 // error
54+
| ^^^^
55+
| value += is not a member of Int - did you mean (1 : Int).!=? or perhaps (1 : Int).<=?

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