IR: use inlineClassRepresentation in getInlineClassUnderlyingType

Looking for the primary constructor manually doesn't work if it's
private in the other module on JVM, because private declarations are
skipped in IrLazyClass.

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/lower/indy/LambdaMetafactoryArguments.kt

@@ -481,8 +481,7 @@ internal class LambdaMetafactoryArgumentsBuilder(
         if (erasedAdapteeClass.isInline) {
             // Inline classes mapped to non-null reference types are a special case because they can't be boxed trivially.
             // TODO consider adding a special type annotation to force boxing on an inline class type regardless of its underlying type.
-            val underlyingAdapteeType = getInlineClassUnderlyingType(erasedAdapteeClass) as? IrSimpleType
-                ?: throw AssertionError("Underlying type for inline class should be a simple type: ${erasedAdapteeClass.render()}")
+            val underlyingAdapteeType = getInlineClassUnderlyingType(erasedAdapteeClass)
             if (!underlyingAdapteeType.hasQuestionMark && !underlyingAdapteeType.isPrimitiveType()) {
                 return TypeAdaptationConstraint.CONFLICT
             }

compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/ir2wasm/TypeTransformer.kt

@@ -14,7 +14,6 @@ import org.jetbrains.kotlin.ir.symbols.IrTypeParameterSymbol
 import org.jetbrains.kotlin.ir.types.IrType
 import org.jetbrains.kotlin.ir.types.classifierOrNull
 import org.jetbrains.kotlin.ir.types.getClass
-import org.jetbrains.kotlin.ir.util.getInlineClassUnderlyingType
 import org.jetbrains.kotlin.ir.util.isInterface
 import org.jetbrains.kotlin.wasm.ir.*
 
@@ -97,7 +96,7 @@ class WasmTypeTransformer(
                 if (klass != null && klass.hasWasmForeignAnnotation()) {
                     WasmExternRef
                 } else if (ic != null) {
-                    getInlineClassUnderlyingType(ic).toWasmValueType()
+                    context.backendContext.inlineClassesUtils.getInlineClassUnderlyingType(ic).toWasmValueType()
                 } else {
                     this.toWasmGcRefType()
                 }

compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/utils/WasmInlineClassesUtils.kt

@@ -9,10 +9,12 @@ import org.jetbrains.kotlin.backend.wasm.WasmSymbols
 import org.jetbrains.kotlin.ir.backend.js.InlineClassesUtils
 import org.jetbrains.kotlin.ir.backend.js.utils.erase
 import org.jetbrains.kotlin.ir.declarations.IrClass
+import org.jetbrains.kotlin.ir.declarations.IrConstructor
 import org.jetbrains.kotlin.ir.symbols.IrSimpleFunctionSymbol
 import org.jetbrains.kotlin.ir.types.IrSimpleType
 import org.jetbrains.kotlin.ir.types.IrType
 import org.jetbrains.kotlin.ir.types.isNullable
+import org.jetbrains.kotlin.ir.util.fqNameWhenAvailable
 
 class WasmInlineClassesUtils(private val wasmSymbols: WasmSymbols) : InlineClassesUtils {
     override fun isTypeInlined(type: IrType): Boolean {
@@ -42,4 +44,17 @@ class WasmInlineClassesUtils(private val wasmSymbols: WasmSymbols) : InlineClass
 
     override val unboxIntrinsic: IrSimpleFunctionSymbol
         get() = wasmSymbols.unboxIntrinsic
-}
+
+    /**
+     * Unlike [org.jetbrains.kotlin.ir.util.getInlineClassUnderlyingType], doesn't use [IrClass.inlineClassRepresentation] because
+     * for some reason it can be called for classes which are not inline, e.g. `kotlin.Double`.
+     */
+    fun getInlineClassUnderlyingType(irClass: IrClass): IrType {
+        for (declaration in irClass.declarations) {
+            if (declaration is IrConstructor && declaration.isPrimary) {
+                return declaration.valueParameters[0].type
+            }
+        }
+        error("Class has no primary constructor: ${irClass.fqNameWhenAvailable}")
+    }
+}

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/util/InlineClasses.kt

@@ -6,18 +6,13 @@
 package org.jetbrains.kotlin.ir.util
 
 import org.jetbrains.kotlin.ir.declarations.IrClass
-import org.jetbrains.kotlin.ir.declarations.IrConstructor
 import org.jetbrains.kotlin.ir.declarations.IrField
 import org.jetbrains.kotlin.ir.declarations.IrProperty
-import org.jetbrains.kotlin.ir.types.IrType
+import org.jetbrains.kotlin.ir.types.IrSimpleType
 
-fun getInlineClassUnderlyingType(irClass: IrClass): IrType {
-    for (declaration in irClass.declarations) {
-        if (declaration is IrConstructor && declaration.isPrimary) {
-            return declaration.valueParameters[0].type
-        }
-    }
-    error("Inline class has no primary constructor: ${irClass.fqNameWhenAvailable}")
+fun getInlineClassUnderlyingType(irClass: IrClass): IrSimpleType {
+    val representation = irClass.inlineClassRepresentation ?: error("Not an inline class: ${irClass.render()}")
+    return representation.underlyingType
 }
 
 fun getInlineClassBackingField(irClass: IrClass): IrField {