[IR] Add IrSymbolBase.toString() implementation

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/codegen/ExpressionCodegen.kt

@@ -590,8 +590,7 @@ class ExpressionCodegen(
         val index = frameMap.getIndex(irSymbol)
         if (index >= 0)
             return index
-        val dump = if (irSymbol.isBound) irSymbol.owner.dump() else "??? unbound symbol ???"
+        throw AssertionError("Non-mapped local declaration: $irSymbol\n in ${irFunction.dump()}")
-        throw AssertionError("Non-mapped local declaration: $dump\n in ${irFunction.dump()}")
     }
 
     private fun handlePlusMinus(expression: IrSetVariable, value: IrExpression?, isMinus: Boolean): Boolean {

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/symbols/impl/IrPrivateSymbolBase.kt

@@ -22,8 +22,14 @@ import org.jetbrains.kotlin.ir.descriptors.*
 import org.jetbrains.kotlin.ir.expressions.IrReturnableBlock
 import org.jetbrains.kotlin.ir.symbols.*
 import org.jetbrains.kotlin.ir.util.IdSignature
+import org.jetbrains.kotlin.ir.util.dump
 
-abstract class IrSymbolBase<out D : DeclarationDescriptor>(override val descriptor: D) : IrSymbol
+abstract class IrSymbolBase<out D : DeclarationDescriptor>(override val descriptor: D) : IrSymbol {
+    override fun toString(): String {
+        if (isBound) return owner.dump()
+        return "Unbound private symbol ${super.toString()}"
+    }
+}
 
 abstract class IrBindableSymbolBase<out D : DeclarationDescriptor, B : IrSymbolOwner>(descriptor: D) :
     IrBindableSymbol<D, B>, IrSymbolBase<D>(descriptor) {
@@ -48,7 +54,7 @@ abstract class IrBindableSymbolBase<out D : DeclarationDescriptor, B : IrSymbolO
 
     private var _owner: B? = null
     override val owner: B
-        get() = _owner ?: throw IllegalStateException("Symbol is unbound")
+        get() = _owner ?: throw IllegalStateException("Symbol with ${javaClass.simpleName} is unbound")
 
     override fun bind(owner: B) {
         if (_owner == null) {

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/symbols/impl/IrPublicSymbolBase.kt

@@ -10,8 +10,17 @@ import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.descriptors.WrappedDeclarationDescriptor
 import org.jetbrains.kotlin.ir.symbols.*
 import org.jetbrains.kotlin.ir.util.IdSignature
+import org.jetbrains.kotlin.ir.util.dump
 
-abstract class IrPublicSymbolBase<out D : DeclarationDescriptor>(override val descriptor: D, override val signature: IdSignature) : IrSymbol
+abstract class IrPublicSymbolBase<out D : DeclarationDescriptor>(
+    override val descriptor: D,
+    override val signature: IdSignature
+) : IrSymbol {
+    override fun toString(): String {
+        if (isBound) return owner.dump()
+        return "Unbound public symbol for $signature"
+    }
+}
 
 abstract class IrBindablePublicSymbolBase<out D : DeclarationDescriptor, B : IrSymbolOwner>(descriptor: D, sig: IdSignature) :
     IrBindableSymbol<D, B>, IrPublicSymbolBase<D>(descriptor, sig) {