Added 'NoInfer' and 'Exact' annotations

core/builtins/src/kotlin/Annotations.kt

@@ -118,3 +118,17 @@ public annotation class HiddenDeclaration
 @Retention(SOURCE)
 @MustBeDocumented
 private annotation class external
+
+/**
+ * Specifies that the corresponding type should be ignored during type inference.
+ */
+@Target(TYPE)
+@Retention(SOURCE)
+internal annotation class NoInfer
+
+/**
+ * Specifies that the constraint built for the type during type inference should be an equality one.
+ */
+@Target(TYPE)
+@Retention(SOURCE)
+internal annotation class Exact

core/descriptors/src/org/jetbrains/kotlin/resolve/annotationsForResolve.kt

@@ -17,8 +17,17 @@
 package org.jetbrains.kotlin.resolve.descriptorUtil
 
 import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
+import org.jetbrains.kotlin.descriptors.annotations.Annotated
 import org.jetbrains.kotlin.name.FqName
 
 private val HIDDEN_ANNOTATION_FQ_NAME = FqName("kotlin.HiddenDeclaration")
 
 public fun DeclarationDescriptor.isAnnotatedAsHidden(): Boolean = annotations.findAnnotation(HIDDEN_ANNOTATION_FQ_NAME) != null
+
+private val NO_INFER_ANNOTATION_FQ_NAME = FqName("kotlin.NoInfer")
+
+public fun Annotated.hasNoInferAnnotation(): Boolean = annotations.findAnnotation(NO_INFER_ANNOTATION_FQ_NAME) != null
+
+private val EXACT_ANNOTATION_FQ_NAME = FqName("kotlin.Exact")
+
+public fun Annotated.hasExactAnnotation(): Boolean = annotations.findAnnotation(EXACT_ANNOTATION_FQ_NAME) != null

core/descriptors/src/org/jetbrains/kotlin/resolve/calls/inference/ConstraintSystemImpl.kt

@@ -29,6 +29,8 @@ import org.jetbrains.kotlin.resolve.calls.inference.constraintPosition.Constrain
 import org.jetbrains.kotlin.resolve.calls.inference.constraintPosition.ConstraintPositionKind
 import org.jetbrains.kotlin.resolve.calls.inference.constraintPosition.ConstraintPositionKind.TYPE_BOUND_POSITION
 import org.jetbrains.kotlin.resolve.calls.inference.constraintPosition.derivedFrom
+import org.jetbrains.kotlin.resolve.descriptorUtil.hasNoInferAnnotation
+import org.jetbrains.kotlin.resolve.descriptorUtil.hasExactAnnotation
 import org.jetbrains.kotlin.resolve.scopes.JetScope
 import org.jetbrains.kotlin.types.*
 import org.jetbrains.kotlin.types.TypeUtils.DONT_CARE
@@ -286,6 +288,11 @@ public class ConstraintSystemImpl : ConstraintSystem {
         if (isErrorOrSpecialType(subType, constraintPosition) || isErrorOrSpecialType(superType, constraintPosition)) return
         if (subType == null || superType == null) return
 
+        if (subType.hasNoInferAnnotation() || superType.hasNoInferAnnotation()) return
+        if ((subType.hasExactAnnotation() || superType.hasExactAnnotation()) && (constraintKind != EQUAL)) {
+            return doAddConstraint(EQUAL, subType, superType, constraintContext, typeCheckingProcedure)
+        }
+
         assert(!superType.isFunctionPlaceholder) {
             "The type for " + constraintPosition + " shouldn't be a placeholder for function type"
         }