backend-api: add source locations to IrClass and IrClass.MemberVariable

Author: tmarsteel

backend-api/src/main/kotlin/io/github/tmarsteel/emerge/backend/api/ir/basetype.kt

@@ -44,6 +44,8 @@ interface IrClass : IrBaseType {
 
     val destructor: IrFunction
 
+    val declaredAt: IrSourceLocation
+
     interface MemberVariable {
         val name: String
 
@@ -59,6 +61,8 @@ interface IrClass : IrBaseType {
          */
         val writeStrategy: AccessStrategy
 
+        val declaredAt: IrSourceLocation
+
         sealed interface AccessStrategy {
             /**
              * The member variable is supposed to be read/written by directly accessing the [Field] with [Field.id] == [BareField.fieldId].

frontend/src/main/kotlin/compiler/binding/basetype/BoundBaseType.kt

@@ -583,6 +583,7 @@ private class IrClassImpl(
     override val memberFunctions by lazy { typeDef.memberFunctions.map { it.toBackendIr() as IrOverloadGroup<IrMemberFunction> } }
     override val constructor by lazy { typeDef.constructor!!.toBackendIr() }
     override val destructor by lazy { typeDef.destructor!!.toBackendIr() }
+    override val declaredAt by lazy { typeDef.declaration.declaredAt }
 
     override fun equals(other: Any?): Boolean {
         if (this === other) return true

frontend/src/main/kotlin/compiler/binding/basetype/BoundBaseTypeMemberVariable.kt

@@ -34,6 +34,7 @@ import compiler.diagnostic.decoratingMemberVariableWithoutConstructorInitializat
 import compiler.diagnostic.quoteIdentifier
 import compiler.lexer.Span
 import io.github.tmarsteel.emerge.backend.api.ir.IrClass
+import io.github.tmarsteel.emerge.backend.api.ir.IrSourceLocation
 import io.github.tmarsteel.emerge.backend.api.ir.IrType
 
 class BoundBaseTypeMemberVariable(
@@ -127,7 +128,7 @@ class BoundBaseTypeMemberVariable(
     override fun toStringForErrorMessage() = "member variable ${name.quoteIdentifier()}"
 
     private val _backendIr by lazy {
-        IrClassMemberVariableImpl(name, type!!.toBackendIr(), field.id)
+        IrClassMemberVariableImpl(name, type!!.toBackendIr(), field.id, declaredAt)
     }
     fun toBackendIr(): IrClass.MemberVariable = _backendIr
 
@@ -138,6 +139,7 @@ private class IrClassMemberVariableImpl(
     override val name: String,
     override val type: IrType,
     private val fieldId: Int,
+    override val declaredAt: IrSourceLocation,
 ) : IrClass.MemberVariable {
     override val readStrategy = object : IrClass.MemberVariable.AccessStrategy.BareField {
         override val fieldId: Int = this@IrClassMemberVariableImpl.fieldId