From 21d48c8336840f7d9a342d8f860037a440725708 Mon Sep 17 00:00:00 2001
From: Som Snytt <som.snytt@gmail.com>
Date: Mon, 24 Mar 2025 18:29:47 -0700
Subject: [PATCH] Use other tree for actual symbol of Assign
---
compiler/src/dotty/tools/dotc/ast/Trees.scala | 7 +-
.../tools/dotc/printing/Formatting.scala | 5 +-
.../dotty/tools/dotc/reporting/messages.scala | 26 +++--
.../src/dotty/tools/dotc/typer/Dynamic.scala | 11 +--
.../src/dotty/tools/dotc/typer/Typer.scala | 14 ++-
tests/neg/assignments.check | 12 +++
tests/neg/i11561.check | 2 +-
tests/neg/i16655.check | 2 +-
tests/neg/i20338c.check | 2 +-
tests/neg/i22671.check | 61 ++++++++++++
tests/neg/i22671.explain.check | 94 +++++++++++++++++++
tests/neg/i22671.explain.scala | 32 +++++++
tests/neg/i22671.scala | 49 ++++++++++
13 files changed, 287 insertions(+), 30 deletions(-)
create mode 100644 tests/neg/assignments.check
create mode 100644 tests/neg/i22671.check
create mode 100644 tests/neg/i22671.explain.check
create mode 100644 tests/neg/i22671.explain.scala
create mode 100644 tests/neg/i22671.scala
diff --git a/compiler/src/dotty/tools/dotc/ast/Trees.scala b/compiler/src/dotty/tools/dotc/ast/Trees.scala
index fdefc14aadd6..561411857688 100644
--- a/compiler/src/dotty/tools/dotc/ast/Trees.scala
+++ b/compiler/src/dotty/tools/dotc/ast/Trees.scala
@@ -1821,16 +1821,15 @@ object Trees {
}
}
- def rename(tree: NameTree, newName: Name)(using Context): tree.ThisTree[T] = {
- tree match {
+ def rename(tree: NameTree, newName: Name)(using Context): tree.ThisTree[T] =
+ tree.match
case tree: Ident => cpy.Ident(tree)(newName)
case tree: Select => cpy.Select(tree)(tree.qualifier, newName)
case tree: Bind => cpy.Bind(tree)(newName, tree.body)
case tree: ValDef => cpy.ValDef(tree)(name = newName.asTermName)
case tree: DefDef => cpy.DefDef(tree)(name = newName.asTermName)
case tree: TypeDef => cpy.TypeDef(tree)(name = newName.asTypeName)
- }
- }.asInstanceOf[tree.ThisTree[T]]
+ .asInstanceOf[tree.ThisTree[T]]
object TypeDefs:
def unapply(xs: List[Tree]): Option[List[TypeDef]] = xs match
diff --git a/compiler/src/dotty/tools/dotc/printing/Formatting.scala b/compiler/src/dotty/tools/dotc/printing/Formatting.scala
index 741b997d9926..5b05982ccbaa 100644
--- a/compiler/src/dotty/tools/dotc/printing/Formatting.scala
+++ b/compiler/src/dotty/tools/dotc/printing/Formatting.scala
@@ -8,7 +8,7 @@ import core.*
import Texts.*, Types.*, Flags.*, Symbols.*, Contexts.*
import Decorators.*
import reporting.Message
-import util.{DiffUtil, SimpleIdentitySet}
+import util.{Chars, DiffUtil, SimpleIdentitySet}
import Highlighting.*
object Formatting {
@@ -169,7 +169,8 @@ object Formatting {
}
def assemble(args: Seq[Shown])(using Context): String = {
- def isLineBreak(c: Char) = c == '\n' || c == '\f' // compatible with StringLike#isLineBreak
+ // compatible with CharArrayReader (not StringOps)
+ inline def isLineBreak(c: Char) = c == Chars.LF || c == Chars.FF
def stripTrailingPart(s: String) = {
val (pre, post) = s.span(c => !isLineBreak(c))
pre ++ post.stripMargin
diff --git a/compiler/src/dotty/tools/dotc/reporting/messages.scala b/compiler/src/dotty/tools/dotc/reporting/messages.scala
index dcd7ed10987b..79d64c0d1cef 100644
--- a/compiler/src/dotty/tools/dotc/reporting/messages.scala
+++ b/compiler/src/dotty/tools/dotc/reporting/messages.scala
@@ -1526,18 +1526,24 @@ class AmbiguousExtensionMethod(tree: untpd.Tree, expansion1: tpd.Tree, expansion
|are possible expansions of $tree"""
def explain(using Context) = ""
-class ReassignmentToVal(name: Name)(using Context)
- extends TypeMsg(ReassignmentToValID) {
- def msg(using Context) = i"""Reassignment to val $name"""
- def explain(using Context) =
- i"""|You can not assign a new value to $name as values can't be changed.
- |Keep in mind that every statement has a value, so you may e.g. use
- | ${hl("val")} $name ${hl("= if (condition) 2 else 5")}
- |In case you need a reassignable name, you can declare it as
- |variable
+class ReassignmentToVal(sym: Symbol, usage: Name)(using Context) extends TypeMsg(ReassignmentToValID):
+ private def name = if sym.exists then sym.name else usage
+ private def addendum = if !sym.exists || !sym.owner.isClass then "" else
+ i"""|
+ |Also, assignment syntax can be used if there is a corresponding setter:
+ | ${hl("def")} ${name}${hl("_=(x: Int): Unit = _v = x")}
+ |"""
+ def msg(using Context) =
+ if sym.exists then i"""Assignment to $sym"""
+ else i"""Bad assignment to $usage"""
+ def explain(using Context) =
+ i"""|Members defined using `val` or `def` can't be assigned to.
+ |If you need to change the value of $name, use `var` instead:
| ${hl("var")} $name ${hl("=")} ...
+ |However, it's more common to initialize a variable just once
+ |with a complex expression or even a block with many statements:
+ | ${hl("val")} $name ${hl("= if (condition) 1 else -1")}$addendum
|"""
-}
class TypeDoesNotTakeParameters(tpe: Type, params: List[untpd.Tree])(using Context)
extends TypeMsg(TypeDoesNotTakeParametersID) {
diff --git a/compiler/src/dotty/tools/dotc/typer/Dynamic.scala b/compiler/src/dotty/tools/dotc/typer/Dynamic.scala
index 14cc7bf963a6..d660fd3c41ad 100644
--- a/compiler/src/dotty/tools/dotc/typer/Dynamic.scala
+++ b/compiler/src/dotty/tools/dotc/typer/Dynamic.scala
@@ -128,18 +128,17 @@ trait Dynamic {
/** Translate selection that does not typecheck according to the normal rules into a updateDynamic.
* foo.bar = baz ~~> foo.updateDynamic(bar)(baz)
*/
- def typedDynamicAssign(tree: untpd.Assign, pt: Type)(using Context): Tree = {
+ def typedDynamicAssign(tree: untpd.Assign, pt: Type)(using Context): Tree =
def typedDynamicAssign(qual: untpd.Tree, name: Name, selSpan: Span, targs: List[untpd.Tree]): Tree =
typedApply(untpd.Apply(coreDynamic(qual, nme.updateDynamic, name, selSpan, targs), tree.rhs), pt)
- tree.lhs match {
+ tree.lhs match
case sel @ Select(qual, name) if !isDynamicMethod(name) =>
typedDynamicAssign(qual, name, sel.span, Nil)
case TypeApply(sel @ Select(qual, name), targs) if !isDynamicMethod(name) =>
typedDynamicAssign(qual, name, sel.span, targs)
- case _ =>
- errorTree(tree, ReassignmentToVal(tree.lhs.symbol.name))
- }
- }
+ case lhs =>
+ val name = lhs match { case nt: NameTree => nt.name case _ => nme.NO_NAME }
+ errorTree(tree, ReassignmentToVal(lhs.symbol, name))
private def coreDynamic(qual: untpd.Tree, dynName: Name, name: Name, selSpan: Span, targs: List[untpd.Tree])(using Context): untpd.Apply = {
val select = untpd.Select(qual, dynName).withSpan(selSpan)
diff --git a/compiler/src/dotty/tools/dotc/typer/Typer.scala b/compiler/src/dotty/tools/dotc/typer/Typer.scala
index 6b7b840e7606..cbbf9a8c3de0 100644
--- a/compiler/src/dotty/tools/dotc/typer/Typer.scala
+++ b/compiler/src/dotty/tools/dotc/typer/Typer.scala
@@ -1373,9 +1373,11 @@ class Typer(@constructorOnly nestingLevel: Int = 0) extends Namer
def typedAssign(tree: untpd.Assign, pt: Type)(using Context): Tree =
tree.lhs match {
- case lhs @ Apply(fn, args) =>
- typed(untpd.Apply(untpd.Select(fn, nme.update), args :+ tree.rhs), pt)
- case untpd.TypedSplice(Apply(MaybePoly(Select(fn, app), targs), args)) if app == nme.apply =>
+ case Apply(fn, args) =>
+ val appliedUpdate =
+ untpd.Apply(untpd.Select(fn, nme.update), args :+ tree.rhs)
+ typed(appliedUpdate, pt)
+ case untpd.TypedSplice(Apply(MaybePoly(Select(fn, nme.apply), targs), args)) =>
val rawUpdate: untpd.Tree = untpd.Select(untpd.TypedSplice(fn), nme.update)
val wrappedUpdate =
if (targs.isEmpty) rawUpdate
@@ -1389,7 +1391,8 @@ class Typer(@constructorOnly nestingLevel: Int = 0) extends Namer
def lhs1 = adapt(lhsCore, LhsProto, locked)
def reassignmentToVal =
- report.error(ReassignmentToVal(lhsCore.symbol.name), tree.srcPos)
+ val name = lhs match { case nt: NameTree => nt.name case _ => nme.NO_NAME }
+ report.error(ReassignmentToVal(lhs1.symbol, name), tree.srcPos)
cpy.Assign(tree)(lhsCore, typed(tree.rhs, lhs1.tpe.widen)).withType(defn.UnitType)
def canAssign(sym: Symbol) =
@@ -1478,8 +1481,9 @@ class Typer(@constructorOnly nestingLevel: Int = 0) extends Namer
typedDynamicAssign(tree, pt)
case tpe =>
reassignmentToVal
- }
+ }
}
+ end typedAssign
def typedBlockStats(stats: List[untpd.Tree])(using Context): (List[tpd.Tree], Context) =
index(stats)
diff --git a/tests/neg/assignments.check b/tests/neg/assignments.check
new file mode 100644
index 000000000000..e42b50ccc8d9
--- /dev/null
+++ b/tests/neg/assignments.check
@@ -0,0 +1,12 @@
+-- [E052] Type Error: tests/neg/assignments.scala:16:8 -----------------------------------------------------------------
+16 | x_= = 2 // error should give missing arguments
+ | ^^^^^^^
+ | Bad assignment to x_=
+ |
+ | longer explanation available when compiling with `-explain`
+-- [E083] Type Error: tests/neg/assignments.scala:20:9 -----------------------------------------------------------------
+20 | import c._ // error should give: prefix is not stable
+ | ^
+ | (assignments.c : assignments.C) is not a valid import prefix, since it is not an immutable path
+ |
+ | longer explanation available when compiling with `-explain`
diff --git a/tests/neg/i11561.check b/tests/neg/i11561.check
index 28d7e355c499..c9d11dbc68fc 100644
--- a/tests/neg/i11561.check
+++ b/tests/neg/i11561.check
@@ -11,6 +11,6 @@
-- [E052] Type Error: tests/neg/i11561.scala:3:30 ----------------------------------------------------------------------
3 | val updateText2 = copy(text = (_: String)) // error
| ^^^^^^^^^^^^^^^^^^
- | Reassignment to val text
+ | Assignment to value text
|
| longer explanation available when compiling with `-explain`
diff --git a/tests/neg/i16655.check b/tests/neg/i16655.check
index e1335b624244..e9fbeb56adb8 100644
--- a/tests/neg/i16655.check
+++ b/tests/neg/i16655.check
@@ -1,6 +1,6 @@
-- [E052] Type Error: tests/neg/i16655.scala:3:4 -----------------------------------------------------------------------
3 | x = 5 // error
| ^^^^^
- | Reassignment to val x
+ | Assignment to value x
|
| longer explanation available when compiling with `-explain`
diff --git a/tests/neg/i20338c.check b/tests/neg/i20338c.check
index 1d19ec0b3042..fa8e05de4641 100644
--- a/tests/neg/i20338c.check
+++ b/tests/neg/i20338c.check
@@ -1,6 +1,6 @@
-- [E052] Type Error: tests/neg/i20338c.scala:9:6 ----------------------------------------------------------------------
9 | f.x = 42 // error
| ^^^^^^^^
- | Reassignment to val x
+ | Assignment to value x
|
| longer explanation available when compiling with `-explain`
diff --git a/tests/neg/i22671.check b/tests/neg/i22671.check
new file mode 100644
index 000000000000..0ea9768a0bb8
--- /dev/null
+++ b/tests/neg/i22671.check
@@ -0,0 +1,61 @@
+-- [E007] Type Mismatch Error: tests/neg/i22671.scala:41:22 ------------------------------------------------------------
+41 | names_times(fields(0)) += fields(1).toLong // error
+ | ^^^^^^^^^
+ | Found: Char
+ | Required: String
+ |
+ | longer explanation available when compiling with `-explain`
+-- [E008] Not Found Error: tests/neg/i22671.scala:45:6 -----------------------------------------------------------------
+45 | x() += "42" // error
+ | ^^^^^^
+ | value += is not a member of Int - did you mean Int.!=? or perhaps Int.<=?
+-- [E052] Type Error: tests/neg/i22671.scala:49:6 ----------------------------------------------------------------------
+49 | c = 42 // error
+ | ^^^^^^
+ | Assignment to value c
+ |
+ | longer explanation available when compiling with `-explain`
+-- [E052] Type Error: tests/neg/i22671.scala:9:6 -----------------------------------------------------------------------
+9 | X.w = 27 // error
+ | ^^^^^^^^
+ | Assignment to value w
+ |
+ | longer explanation available when compiling with `-explain`
+-- [E052] Type Error: tests/neg/i22671.scala:12:6 ----------------------------------------------------------------------
+12 | X.x = 27 // error
+ | ^^^^^^^^
+ | Assignment to method x
+ |
+ | longer explanation available when compiling with `-explain`
+-- [E052] Type Error: tests/neg/i22671.scala:16:4 ----------------------------------------------------------------------
+16 | x = 27 // error
+ | ^^^^^^
+ | Assignment to method x
+ |
+ | longer explanation available when compiling with `-explain`
+-- [E052] Type Error: tests/neg/i22671.scala:20:4 ----------------------------------------------------------------------
+20 | y = 27 // error
+ | ^^^^^^
+ | Assignment to method x
+ |
+ | longer explanation available when compiling with `-explain`
+-- [E052] Type Error: tests/neg/i22671.scala:24:4 ----------------------------------------------------------------------
+24 | y = 27 // error
+ | ^^^^^^
+ | Assignment to value z
+ |
+ | longer explanation available when compiling with `-explain`
+-- [E052] Type Error: tests/neg/i22671.scala:28:4 ----------------------------------------------------------------------
+28 | x = 27 // error
+ | ^^^^^^
+ | Assignment to value x
+ |
+ | longer explanation available when compiling with `-explain`
+-- [E008] Not Found Error: tests/neg/i22671.scala:31:6 -----------------------------------------------------------------
+31 | X.x += 27 // error
+ | ^^^^^^
+ | value += is not a member of Int - did you mean Int.!=? or perhaps Int.<=?
+-- [E008] Not Found Error: tests/neg/i22671.scala:32:4 -----------------------------------------------------------------
+32 | 1 += 1 // error
+ | ^^^^
+ | value += is not a member of Int - did you mean (1 : Int).!=? or perhaps (1 : Int).<=?
diff --git a/tests/neg/i22671.explain.check b/tests/neg/i22671.explain.check
new file mode 100644
index 000000000000..72ea32eddcf2
--- /dev/null
+++ b/tests/neg/i22671.explain.check
@@ -0,0 +1,94 @@
+-- [E052] Type Error: tests/neg/i22671.explain.scala:14:6 --------------------------------------------------------------
+14 | X.w = 27 // error
+ | ^^^^^^^^
+ | Assignment to value w
+ |--------------------------------------------------------------------------------------------------------------------
+ | Explanation (enabled by `-explain`)
+ |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+ | Members defined using `val` or `def` can't be assigned to.
+ | If you need to change the value of w, use `var` instead:
+ | var w = ...
+ | However, it's more common to initialize a variable just once
+ | with a complex expression or even a block with many statements:
+ | val w = if (condition) 1 else -1
+ | Also, assignment syntax can be used if there is a corresponding setter:
+ | def w_=(x: Int): Unit = _v = x
+ --------------------------------------------------------------------------------------------------------------------
+-- [E052] Type Error: tests/neg/i22671.explain.scala:17:6 --------------------------------------------------------------
+17 | X.x = 27 // error
+ | ^^^^^^^^
+ | Assignment to method x
+ |--------------------------------------------------------------------------------------------------------------------
+ | Explanation (enabled by `-explain`)
+ |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+ | Members defined using `val` or `def` can't be assigned to.
+ | If you need to change the value of x, use `var` instead:
+ | var x = ...
+ | However, it's more common to initialize a variable just once
+ | with a complex expression or even a block with many statements:
+ | val x = if (condition) 1 else -1
+ | Also, assignment syntax can be used if there is a corresponding setter:
+ | def x_=(x: Int): Unit = _v = x
+ --------------------------------------------------------------------------------------------------------------------
+-- [E052] Type Error: tests/neg/i22671.explain.scala:21:4 --------------------------------------------------------------
+21 | y = 27 // error overload renamed
+ | ^^^^^^
+ | Assignment to method x
+ |--------------------------------------------------------------------------------------------------------------------
+ | Explanation (enabled by `-explain`)
+ |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+ | Members defined using `val` or `def` can't be assigned to.
+ | If you need to change the value of x, use `var` instead:
+ | var x = ...
+ | However, it's more common to initialize a variable just once
+ | with a complex expression or even a block with many statements:
+ | val x = if (condition) 1 else -1
+ | Also, assignment syntax can be used if there is a corresponding setter:
+ | def x_=(x: Int): Unit = _v = x
+ --------------------------------------------------------------------------------------------------------------------
+-- [E052] Type Error: tests/neg/i22671.explain.scala:25:4 --------------------------------------------------------------
+25 | y = 27 // error val renamed
+ | ^^^^^^
+ | Assignment to value z
+ |--------------------------------------------------------------------------------------------------------------------
+ | Explanation (enabled by `-explain`)
+ |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+ | Members defined using `val` or `def` can't be assigned to.
+ | If you need to change the value of z, use `var` instead:
+ | var z = ...
+ | However, it's more common to initialize a variable just once
+ | with a complex expression or even a block with many statements:
+ | val z = if (condition) 1 else -1
+ | Also, assignment syntax can be used if there is a corresponding setter:
+ | def z_=(x: Int): Unit = _v = x
+ --------------------------------------------------------------------------------------------------------------------
+-- [E052] Type Error: tests/neg/i22671.explain.scala:29:4 --------------------------------------------------------------
+29 | x = 27 // error local
+ | ^^^^^^
+ | Assignment to value x
+ |--------------------------------------------------------------------------------------------------------------------
+ | Explanation (enabled by `-explain`)
+ |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+ | Members defined using `val` or `def` can't be assigned to.
+ | If you need to change the value of x, use `var` instead:
+ | var x = ...
+ | However, it's more common to initialize a variable just once
+ | with a complex expression or even a block with many statements:
+ | val x = if (condition) 1 else -1
+ --------------------------------------------------------------------------------------------------------------------
+-- [E052] Type Error: tests/neg/i22671.explain.scala:32:6 --------------------------------------------------------------
+32 | t.t = t // error
+ | ^^^^^^^
+ | Assignment to method t
+ |--------------------------------------------------------------------------------------------------------------------
+ | Explanation (enabled by `-explain`)
+ |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+ | Members defined using `val` or `def` can't be assigned to.
+ | If you need to change the value of t, use `var` instead:
+ | var t = ...
+ | However, it's more common to initialize a variable just once
+ | with a complex expression or even a block with many statements:
+ | val t = if (condition) 1 else -1
+ | Also, assignment syntax can be used if there is a corresponding setter:
+ | def t_=(x: Int): Unit = _v = x
+ --------------------------------------------------------------------------------------------------------------------
diff --git a/tests/neg/i22671.explain.scala b/tests/neg/i22671.explain.scala
new file mode 100644
index 000000000000..1b78caf76326
--- /dev/null
+++ b/tests/neg/i22671.explain.scala
@@ -0,0 +1,32 @@
+//> using options -explain
+
+object X:
+ val w: Int = 42
+ def w(y: Int): Int = x + y
+ def x: Int = 42
+ def x(y: Int): Int = x + y
+ val z = 26
+
+trait T:
+ def t = 42
+
+def w =
+ X.w = 27 // error
+
+def f =
+ X.x = 27 // error
+
+def h =
+ import X.x as y
+ y = 27 // error overload renamed
+
+def i =
+ import X.z as y
+ y = 27 // error val renamed
+
+def j =
+ val x = 42
+ x = 27 // error local
+
+def t(t: T) =
+ t.t = t // error
diff --git a/tests/neg/i22671.scala b/tests/neg/i22671.scala
new file mode 100644
index 000000000000..afb04f4cea73
--- /dev/null
+++ b/tests/neg/i22671.scala
@@ -0,0 +1,49 @@
+object X:
+ val w: Int = 42
+ def w(y: Int): Int = x + y
+ def x: Int = 42
+ def x(y: Int): Int = x + y
+ val z = 26
+
+def w =
+ X.w = 27 // error
+
+def f =
+ X.x = 27 // error
+
+def g =
+ import X.x
+ x = 27 // error
+
+def h =
+ import X.x as y
+ y = 27 // error
+
+def i =
+ import X.z as y
+ y = 27 // error
+
+def j =
+ val x = 42
+ x = 27 // error
+
+def k =
+ X.x += 27 // error
+ 1 += 1 // error
+
+
+object t8763:
+ import collection.mutable
+ def bar(): Unit =
+ val names_times = mutable.Map.empty[String, mutable.Set[Long]]
+ val line = ""
+ val Array(fields) = line.split("\t")
+ names_times(fields(0)) += fields(1).toLong // error
+
+object t9834:
+ object x { def apply() = 42 ; def update(i: Int) = () }
+ x() += "42" // error
+
+class C(c: Int):
+ def test(): Unit =
+ c = 42 // error