Report error on using reflection without kotlin-reflect.jar in classpath

Should be a warning because strictly speaking, the codegen doesn't need it
during the compilation. It's an error at the moment only to let all clients of
Kotlin reflection know that they must include kotlin-reflect.jar in the
classpath

compiler/backend/src/org/jetbrains/kotlin/codegen/ExpressionCodegen.java

@@ -65,6 +65,7 @@ import org.jetbrains.kotlin.resolve.constants.CompileTimeConstant;
 import org.jetbrains.kotlin.resolve.constants.IntegerValueTypeConstant;
 import org.jetbrains.kotlin.resolve.constants.evaluate.EvaluatePackage;
 import org.jetbrains.kotlin.resolve.descriptorUtil.DescriptorUtilPackage;
+import org.jetbrains.kotlin.resolve.jvm.diagnostics.ErrorsJvm;
 import org.jetbrains.kotlin.resolve.jvm.jvmSignature.JvmMethodSignature;
 import org.jetbrains.kotlin.resolve.scopes.receivers.*;
 import org.jetbrains.kotlin.types.Approximation;
@@ -97,6 +98,7 @@ import static org.jetbrains.kotlin.resolve.jvm.AsmTypes.*;
 import static org.jetbrains.kotlin.resolve.jvm.diagnostics.DiagnosticsPackage.OtherOrigin;
 import static org.jetbrains.kotlin.resolve.jvm.diagnostics.DiagnosticsPackage.TraitImpl;
 import static org.jetbrains.kotlin.resolve.scopes.receivers.ReceiverValue.NO_RECEIVER;
+import static org.jetbrains.kotlin.serialization.deserialization.DeserializationPackage.findClassAcrossModuleDependencies;
 import static org.jetbrains.org.objectweb.asm.Opcodes.ACC_PRIVATE;
 
 public class ExpressionCodegen extends JetVisitor<StackValue, StackValue> implements LocalLookup {
@@ -2665,6 +2667,8 @@ public class ExpressionCodegen extends JetVisitor<StackValue, StackValue> implem
 
     @Override
     public StackValue visitClassLiteralExpression(@NotNull JetClassLiteralExpression expression, StackValue data) {
+        checkReflectionIsAvailable(expression);
+
         JetType type = bindingContext.get(EXPRESSION_TYPE, expression);
         assert type != null;
 
@@ -2687,25 +2691,34 @@ public class ExpressionCodegen extends JetVisitor<StackValue, StackValue> implem
         }
 
         VariableDescriptor variableDescriptor = bindingContext.get(VARIABLE, expression);
-        if (variableDescriptor != null) {
-            VariableDescriptor descriptor = (VariableDescriptor) resolvedCall.getResultingDescriptor();
-
-            DeclarationDescriptor containingDeclaration = descriptor.getContainingDeclaration();
-            if (containingDeclaration instanceof PackageFragmentDescriptor) {
-                return generateTopLevelPropertyReference(descriptor);
-            }
-            else if (containingDeclaration instanceof ClassDescriptor) {
-                return generateMemberPropertyReference(descriptor, (ClassDescriptor) containingDeclaration);
-            }
-            else if (containingDeclaration instanceof ScriptDescriptor) {
-                return generateMemberPropertyReference(descriptor, ((ScriptDescriptor) containingDeclaration).getClassDescriptor());
-            }
-            else {
-                throw new UnsupportedOperationException("Unsupported callable reference container: " + containingDeclaration);
-            }
+        if (variableDescriptor == null) {
+            throw new UnsupportedOperationException("Unsupported callable reference expression: " + expression.getText());
         }
 
-        throw new UnsupportedOperationException("Unsupported callable reference expression: " + expression.getText());
+        // TODO: this diagnostic should also be reported on function references once they obtain reflection
+        checkReflectionIsAvailable(expression);
+
+        VariableDescriptor descriptor = (VariableDescriptor) resolvedCall.getResultingDescriptor();
+
+        DeclarationDescriptor containingDeclaration = descriptor.getContainingDeclaration();
+        if (containingDeclaration instanceof PackageFragmentDescriptor) {
+            return generateTopLevelPropertyReference(descriptor);
+        }
+        else if (containingDeclaration instanceof ClassDescriptor) {
+            return generateMemberPropertyReference(descriptor, (ClassDescriptor) containingDeclaration);
+        }
+        else if (containingDeclaration instanceof ScriptDescriptor) {
+            return generateMemberPropertyReference(descriptor, ((ScriptDescriptor) containingDeclaration).getClassDescriptor());
+        }
+        else {
+            throw new UnsupportedOperationException("Unsupported callable reference container: " + containingDeclaration);
+        }
+    }
+
+    private void checkReflectionIsAvailable(@NotNull JetExpression expression) {
+        if (findClassAcrossModuleDependencies(state.getModule(), JvmAbi.REFLECTION_FACTORY_IMPL) == null) {
+            state.getDiagnostics().report(ErrorsJvm.NO_REFLECTION_IN_CLASS_PATH.on(expression, expression));
+        }
     }
 
     @NotNull

compiler/backend/src/org/jetbrains/kotlin/codegen/state/GenerationState.java

@@ -124,6 +124,8 @@ public class GenerationState {
     @NotNull
     private final ModuleDescriptor module;
 
+    private final DiagnosticSink diagnostics;
+
     @NotNull
     private final Collection<FqName> packagesWithObsoleteParts;
 
@@ -182,6 +184,7 @@ public class GenerationState {
             builderFactory = new OptimizationClassBuilderFactory(builderFactory);
         }
 
+        this.diagnostics = diagnostics;
         this.classFileFactory = new ClassFileFactory(this, new BuilderFactoryForDuplicateSignatureDiagnostics(
                 builderFactory, this.bindingContext, diagnostics));
 
@@ -271,6 +274,11 @@ public class GenerationState {
         return runtimeTypes;
     }
 
+    @NotNull
+    public DiagnosticSink getDiagnostics() {
+        return diagnostics;
+    }
+
     public boolean isInlineEnabled() {
         return !disableInline;
     }