IrType: basic interface & implementation

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/types/IrType.kt

@@ -0,0 +1,22 @@
+/*
+ * Copyright 2010-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.ir.types
+
+import org.jetbrains.kotlin.ir.expressions.IrCall
+import org.jetbrains.kotlin.ir.symbols.IrClassifierSymbol
+import org.jetbrains.kotlin.types.Variance
+
+interface IrType {
+    val classifier: IrClassifierSymbol
+    val hasQuestionMark: Boolean
+    val arguments: List<IrTypeProjection>
+    val annotations: List<IrCall>
+}
+
+interface IrTypeProjection {
+    val variance: Variance
+    val type: IrType
+}

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/types/impl/IrTypeImpl.kt

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+/*
+ * Copyright 2010-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.ir.types.impl
+
+import org.jetbrains.kotlin.ir.expressions.IrCall
+import org.jetbrains.kotlin.ir.symbols.IrClassifierSymbol
+import org.jetbrains.kotlin.ir.types.IrType
+import org.jetbrains.kotlin.ir.types.IrTypeProjection
+import org.jetbrains.kotlin.types.Variance
+
+class IrTypeImpl(
+    override val classifier: IrClassifierSymbol,
+    override val hasQuestionMark: Boolean,
+    override val arguments: List<IrTypeProjection>,
+    override val annotations: List<IrCall>,
+    override val variance: Variance
+) : IrType, IrTypeProjection {
+
+    constructor(
+        classifier: IrClassifierSymbol,
+        hasQuestionMark: Boolean,
+        arguments: List<IrTypeProjection>,
+        annotations: List<IrCall>
+    ) : this(classifier, hasQuestionMark, arguments, annotations, Variance.INVARIANT)
+
+    override val type: IrType get() = this
+}
+
+fun makeTypeProjection(type: IrType, variance: Variance): IrTypeProjection =
+    if (type !is IrTypeImpl || type.variance != variance)
+        IrTypeImpl(
+            type.classifier,
+            type.hasQuestionMark,
+            type.arguments,
+            type.annotations,
+            variance
+        )
+    else
+        type