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Use other tree for actual symbol of Assign
1 parent d519790 commit 21d48c8

13 files changed

+287
-30
lines changed

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

+3-4
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

+3-2
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

+16-10
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

+5-6
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

+9-5
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

+12
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

+1-1
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

+1-1
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

+1-1
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

+61
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,61 @@
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:49:6 ----------------------------------------------------------------------
13+
49 | c = 42 // error
14+
| ^^^^^^
15+
| Assignment to value c
16+
|
17+
| longer explanation available when compiling with `-explain`
18+
-- [E052] Type Error: tests/neg/i22671.scala:9:6 -----------------------------------------------------------------------
19+
9 | X.w = 27 // error
20+
| ^^^^^^^^
21+
| Assignment to value w
22+
|
23+
| longer explanation available when compiling with `-explain`
24+
-- [E052] Type Error: tests/neg/i22671.scala:12:6 ----------------------------------------------------------------------
25+
12 | X.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:16:4 ----------------------------------------------------------------------
31+
16 | x = 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:20:4 ----------------------------------------------------------------------
37+
20 | y = 27 // error
38+
| ^^^^^^
39+
| Assignment to method x
40+
|
41+
| longer explanation available when compiling with `-explain`
42+
-- [E052] Type Error: tests/neg/i22671.scala:24:4 ----------------------------------------------------------------------
43+
24 | y = 27 // error
44+
| ^^^^^^
45+
| Assignment to value z
46+
|
47+
| longer explanation available when compiling with `-explain`
48+
-- [E052] Type Error: tests/neg/i22671.scala:28:4 ----------------------------------------------------------------------
49+
28 | x = 27 // error
50+
| ^^^^^^
51+
| Assignment to value x
52+
|
53+
| longer explanation available when compiling with `-explain`
54+
-- [E008] Not Found Error: tests/neg/i22671.scala:31:6 -----------------------------------------------------------------
55+
31 | X.x += 27 // error
56+
| ^^^^^^
57+
| value += is not a member of Int - did you mean Int.!=? or perhaps Int.<=?
58+
-- [E008] Not Found Error: tests/neg/i22671.scala:32:4 -----------------------------------------------------------------
59+
32 | 1 += 1 // error
60+
| ^^^^
61+
| value += is not a member of Int - did you mean (1 : Int).!=? or perhaps (1 : Int).<=?

‎tests/neg/i22671.explain.check

+94
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,94 @@
1+
-- [E052] Type Error: tests/neg/i22671.explain.scala:14:6 --------------------------------------------------------------
2+
14 | X.w = 27 // error
3+
| ^^^^^^^^
4+
| Assignment to value w
5+
|--------------------------------------------------------------------------------------------------------------------
6+
| Explanation (enabled by `-explain`)
7+
|- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
8+
| Members defined using `val` or `def` can't be assigned to.
9+
| If you need to change the value of w, use `var` instead:
10+
| var w = ...
11+
| However, it's more common to initialize a variable just once
12+
| with a complex expression or even a block with many statements:
13+
| val w = if (condition) 1 else -1
14+
| Also, assignment syntax can be used if there is a corresponding setter:
15+
| def w_=(x: Int): Unit = _v = x
16+
--------------------------------------------------------------------------------------------------------------------
17+
-- [E052] Type Error: tests/neg/i22671.explain.scala:17:6 --------------------------------------------------------------
18+
17 | X.x = 27 // error
19+
| ^^^^^^^^
20+
| Assignment to method x
21+
|--------------------------------------------------------------------------------------------------------------------
22+
| Explanation (enabled by `-explain`)
23+
|- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
24+
| Members defined using `val` or `def` can't be assigned to.
25+
| If you need to change the value of x, use `var` instead:
26+
| var x = ...
27+
| However, it's more common to initialize a variable just once
28+
| with a complex expression or even a block with many statements:
29+
| val x = if (condition) 1 else -1
30+
| Also, assignment syntax can be used if there is a corresponding setter:
31+
| def x_=(x: Int): Unit = _v = x
32+
--------------------------------------------------------------------------------------------------------------------
33+
-- [E052] Type Error: tests/neg/i22671.explain.scala:21:4 --------------------------------------------------------------
34+
21 | y = 27 // error overload renamed
35+
| ^^^^^^
36+
| Assignment to method x
37+
|--------------------------------------------------------------------------------------------------------------------
38+
| Explanation (enabled by `-explain`)
39+
|- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
40+
| Members defined using `val` or `def` can't be assigned to.
41+
| If you need to change the value of x, use `var` instead:
42+
| var x = ...
43+
| However, it's more common to initialize a variable just once
44+
| with a complex expression or even a block with many statements:
45+
| val x = if (condition) 1 else -1
46+
| Also, assignment syntax can be used if there is a corresponding setter:
47+
| def x_=(x: Int): Unit = _v = x
48+
--------------------------------------------------------------------------------------------------------------------
49+
-- [E052] Type Error: tests/neg/i22671.explain.scala:25:4 --------------------------------------------------------------
50+
25 | y = 27 // error val renamed
51+
| ^^^^^^
52+
| Assignment to value z
53+
|--------------------------------------------------------------------------------------------------------------------
54+
| Explanation (enabled by `-explain`)
55+
|- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
56+
| Members defined using `val` or `def` can't be assigned to.
57+
| If you need to change the value of z, use `var` instead:
58+
| var z = ...
59+
| However, it's more common to initialize a variable just once
60+
| with a complex expression or even a block with many statements:
61+
| val z = if (condition) 1 else -1
62+
| Also, assignment syntax can be used if there is a corresponding setter:
63+
| def z_=(x: Int): Unit = _v = x
64+
--------------------------------------------------------------------------------------------------------------------
65+
-- [E052] Type Error: tests/neg/i22671.explain.scala:29:4 --------------------------------------------------------------
66+
29 | x = 27 // error local
67+
| ^^^^^^
68+
| Assignment to value x
69+
|--------------------------------------------------------------------------------------------------------------------
70+
| Explanation (enabled by `-explain`)
71+
|- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
72+
| Members defined using `val` or `def` can't be assigned to.
73+
| If you need to change the value of x, use `var` instead:
74+
| var x = ...
75+
| However, it's more common to initialize a variable just once
76+
| with a complex expression or even a block with many statements:
77+
| val x = if (condition) 1 else -1
78+
--------------------------------------------------------------------------------------------------------------------
79+
-- [E052] Type Error: tests/neg/i22671.explain.scala:32:6 --------------------------------------------------------------
80+
32 | t.t = t // error
81+
| ^^^^^^^
82+
| Assignment to method t
83+
|--------------------------------------------------------------------------------------------------------------------
84+
| Explanation (enabled by `-explain`)
85+
|- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
86+
| Members defined using `val` or `def` can't be assigned to.
87+
| If you need to change the value of t, use `var` instead:
88+
| var t = ...
89+
| However, it's more common to initialize a variable just once
90+
| with a complex expression or even a block with many statements:
91+
| val t = if (condition) 1 else -1
92+
| Also, assignment syntax can be used if there is a corresponding setter:
93+
| def t_=(x: Int): Unit = _v = x
94+
--------------------------------------------------------------------------------------------------------------------

‎tests/neg/i22671.explain.scala

+32
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,32 @@
1+
//> using options -explain
2+
3+
object X:
4+
val w: Int = 42
5+
def w(y: Int): Int = x + y
6+
def x: Int = 42
7+
def x(y: Int): Int = x + y
8+
val z = 26
9+
10+
trait T:
11+
def t = 42
12+
13+
def w =
14+
X.w = 27 // error
15+
16+
def f =
17+
X.x = 27 // error
18+
19+
def h =
20+
import X.x as y
21+
y = 27 // error overload renamed
22+
23+
def i =
24+
import X.z as y
25+
y = 27 // error val renamed
26+
27+
def j =
28+
val x = 42
29+
x = 27 // error local
30+
31+
def t(t: T) =
32+
t.t = t // error

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