Avoid using the current denotation in NamedType.disambiguate

While recalculating denotation we might call NamedType.disambiguate
which uses a denotation to decide about the correct overloaded method.
Using curretn denotation here might cause stale symbol errors, so instead we use
the lastKnownDenotation, which should be enough for the use case here.

compiler/src/dotty/tools/dotc/core/Denotations.scala

@@ -956,7 +956,7 @@ object Denotations {
     }
 
     def staleSymbolError(using Context): Nothing =
-      if symbol.isPackageObject && ctx.run != null && ctx.run.nn.isCompilingSuspended
+      if symbol.lastKnownDenotation.isPackageObject && ctx.run != null && ctx.run.nn.isCompilingSuspended
       then throw StaleSymbolTypeError(symbol)
       else throw StaleSymbolException(staleSymbolMsg)
 

compiler/src/dotty/tools/dotc/core/TypeErasure.scala

@@ -24,11 +24,16 @@ enum SourceLanguage:
 object SourceLanguage:
   /** The language in which `sym` was defined. */
   def apply(sym: Symbol)(using Context): SourceLanguage =
-    if sym.is(JavaDefined) then
+    // We might be using this method while recalculating the denotation,
+    // so let's use `lastKnownDenotation`.
+    // This is ok as the source of the symbol and whether it is inline should
+    // not change between runs/phases.
+    val denot = sym.lastKnownDenotation
+    if denot.is(JavaDefined) then
       SourceLanguage.Java
     // Scala 2 methods don't have Inline set, except for the ones injected with `patchStdlibClass`
     // which are really Scala 3 methods.
-    else if sym.isClass && sym.is(Scala2x) || (sym.maybeOwner.is(Scala2x) && !sym.is(Inline)) then
+    else if denot.isClass && denot.is(Scala2x) || (denot.maybeOwner.lastKnownDenotation.is(Scala2x) && !denot.is(Inline)) then
       SourceLanguage.Scala2
     else
       SourceLanguage.Scala3

compiler/src/dotty/tools/dotc/core/Types.scala

@@ -2485,7 +2485,7 @@ object Types extends TypeUtils {
     }
 
     private def disambiguate(d: Denotation)(using Context): Denotation =
-      disambiguate(d, currentSignature, currentSymbol.targetName)
+      disambiguate(d, currentSignature, currentSymbol.lastKnownDenotation.targetName)
 
     private def disambiguate(d: Denotation, sig: Signature | Null, target: Name)(using Context): Denotation =
       if (sig != null)

tests/pos-macros/i20574/Exports.scala

@@ -0,0 +1,3 @@
+object Exports{
+  export OverloadedInline.*
+}

tests/pos-macros/i20574/Macros.scala

@@ -0,0 +1,20 @@
+import scala.quoted.*
+
+object Macros{
+
+  inline def A() : String = {
+     ${ A_impl }
+  }
+
+  def A_impl(using Quotes): Expr[String] = {
+    Expr("Whatever")
+  }
+
+  inline def B[T]: Int = {
+    ${ B_Impl[T] }
+  }
+
+  def B_Impl[T](using Quotes): Expr[Int] = {
+    Expr(0)
+  }
+}

tests/pos-macros/i20574/OverloadedInline.scala

@@ -0,0 +1,13 @@
+import Macros.*
+
+object OverloadedInline{
+
+    A()
+    inline def overloaded_inline[T]: Unit = {
+        overloaded_inline[T](0)
+    }
+
+    inline def overloaded_inline[T](dummy: Int): Unit = {
+        val crash = B[T]
+    }
+}

tests/pos-macros/i20574/Test.scala

@@ -0,0 +1,5 @@
+import Exports.*
+
+object Test {
+   overloaded_inline[Unit]
+}