Compiler crashes when a union is used within multiple wait

[IMS94]

Description:
Consider the below code.

import ballerina/log;

type WaitResult record {|
    boolean|error producer;
    boolean consumer;
|};

public function main() {
    log:printInfo("initializing app...");

    // Producer 1
    worker Producer1 returns boolean|error {
        int i = 100;
        i -> Consumer;
        error? unionResult = flush Consumer;
        log:printInfo("Sent item", i = i);
        return true;
    }

    worker Producer2 returns boolean|error {
        int i = 100;
        i -> Consumer;
        error? unionResult = flush Consumer;
        log:printInfo("Sent item", i = i);
        return true;
    }

    // Consumer
    worker Consumer returns boolean {
        int i = <- Producer;
        log:printInfo("Received item", i = i);
        return false;
    }

    WaitResult res = wait {producer: Producer1|Producer2, consumer: Consumer};
    log:printInfo("Worker execution finished", result = res);
}

Note the syntactically incorrect line WaitResult res = wait {producer: Producer1|Producer2, consumer: Consumer};. When compiled, this gives the following crash log:

ballerina: Oh no, something really went wrong. Bad. Sad.

We appreciate it if you can report the code that broke Ballerina in
https://github.com/ballerina-platform/ballerina-lang/issues with the
log you get below and your sample code.

We thank you for helping make us better.

[2022-01-25 13:39:10,008] SEVERE {b7a.log.crash} - class org.wso2.ballerinalang.compiler.semantics.model.types.BUnionType cannot be cast to class org.wso2.ballerinalang.compiler.semantics.model.types.BFutureType (org.wso2.ballerinalang.compiler.semantics.model.types.BUnionType and org.wso2.ballerinalang.compiler.semantics.model.types.BFutureType are in unnamed module of loader 'app') 
java.lang.ClassCastException: class org.wso2.ballerinalang.compiler.semantics.model.types.BUnionType cannot be cast to class org.wso2.ballerinalang.compiler.semantics.model.types.BFutureType (org.wso2.ballerinalang.compiler.semantics.model.types.BUnionType and org.wso2.ballerinalang.compiler.semantics.model.types.BFutureType are in unnamed module of loader 'app')
	at org.wso2.ballerinalang.compiler.semantics.analyzer.TypeChecker.setEventualTypeForExpression(TypeChecker.java:4095)
	at org.wso2.ballerinalang.compiler.semantics.analyzer.TypeChecker.checkWaitKeyValExpr(TypeChecker.java:4083)
	at org.wso2.ballerinalang.compiler.semantics.analyzer.TypeChecker.checkTypesForRecords(TypeChecker.java:4044)
	at org.wso2.ballerinalang.compiler.semantics.analyzer.TypeChecker.setResultTypeForWaitForAllExpr(TypeChecker.java:3935)
	at org.wso2.ballerinalang.compiler.semantics.analyzer.TypeChecker.setResultTypeForWaitForAllExpr(TypeChecker.java:3960)
	at org.wso2.ballerinalang.compiler.semantics.analyzer.TypeChecker.visit(TypeChecker.java:3924)
	at org.wso2.ballerinalang.compiler.tree.expressions.BLangWaitForAllExpr.accept(BLangWaitForAllExpr.java:52)
	at org.wso2.ballerinalang.compiler.semantics.analyzer.TypeChecker.checkExpr(TypeChecker.java:380)
	at org.wso2.ballerinalang.compiler.semantics.analyzer.TypeChecker.checkExpr(TypeChecker.java:354)
	at org.wso2.ballerinalang.compiler.semantics.analyzer.SemanticAnalyzer.visit(SemanticAnalyzer.java:1052)
	at org.wso2.ballerinalang.compiler.tree.BLangSimpleVariable.accept(BLangSimpleVariable.java:54)
	at org.wso2.ballerinalang.compiler.semantics.analyzer.SemanticAnalyzer.analyzeNode(SemanticAnalyzer.java:4057)
	at org.wso2.ballerinalang.compiler.semantics.analyzer.SemanticAnalyzer.analyzeNode(SemanticAnalyzer.java:4028)
	at org.wso2.ballerinalang.compiler.semantics.analyzer.SemanticAnalyzer.analyzeDef(SemanticAnalyzer.java:4020)
	at org.wso2.ballerinalang.compiler.semantics.analyzer.SemanticAnalyzer.visit(SemanticAnalyzer.java:1907)
	at org.wso2.ballerinalang.compiler.tree.statements.BLangSimpleVariableDef.accept(BLangSimpleVariableDef.java:50)
	at org.wso2.ballerinalang.compiler.semantics.analyzer.SemanticAnalyzer.analyzeNode(SemanticAnalyzer.java:4057)
	at org.wso2.ballerinalang.compiler.semantics.analyzer.SemanticAnalyzer.analyzeNode(SemanticAnalyzer.java:4028)
	at org.wso2.ballerinalang.compiler.semantics.analyzer.SemanticAnalyzer.analyzeStmt(SemanticAnalyzer.java:4024)
	at org.wso2.ballerinalang.compiler.semantics.analyzer.SemanticAnalyzer.visit(SemanticAnalyzer.java:524)
	at org.wso2.ballerinalang.compiler.tree.BLangBlockFunctionBody.accept(BLangBlockFunctionBody.java:60)
	at org.wso2.ballerinalang.compiler.semantics.analyzer.SemanticAnalyzer.analyzeNode(SemanticAnalyzer.java:4057)
	at org.wso2.ballerinalang.compiler.semantics.analyzer.SemanticAnalyzer.visit(SemanticAnalyzer.java:500)
	at org.wso2.ballerinalang.compiler.tree.BLangFunction.accept(BLangFunction.java:76)
	at org.wso2.ballerinalang.compiler.semantics.analyzer.SemanticAnalyzer.analyzeNode(SemanticAnalyzer.java:4057)
	at org.wso2.ballerinalang.compiler.semantics.analyzer.SemanticAnalyzer.analyzeNode(SemanticAnalyzer.java:4028)
	at org.wso2.ballerinalang.compiler.semantics.analyzer.SemanticAnalyzer.analyzeDef(SemanticAnalyzer.java:4020)
	at org.wso2.ballerinalang.compiler.semantics.analyzer.SemanticAnalyzer.visit(SemanticAnalyzer.java:349)
	at org.wso2.ballerinalang.compiler.tree.BLangPackage.accept(BLangPackage.java:167)
	at org.wso2.ballerinalang.compiler.semantics.analyzer.SemanticAnalyzer.analyze(SemanticAnalyzer.java:309)
	at io.ballerina.projects.internal.CompilerPhaseRunner.typeCheck(CompilerPhaseRunner.java:188)
	at io.ballerina.projects.internal.CompilerPhaseRunner.performTypeCheckPhases(CompilerPhaseRunner.java:114)
	at io.ballerina.projects.ModuleContext.compileInternal(ModuleContext.java:436)
	at io.ballerina.projects.ModuleCompilationState$1.compile(ModuleCompilationState.java:45)
	at io.ballerina.projects.ModuleContext.compile(ModuleContext.java:386)
	at io.ballerina.projects.PackageCompilation.compileModulesInternal(PackageCompilation.java:213)
	at io.ballerina.projects.PackageCompilation.compileModules(PackageCompilation.java:198)
	at io.ballerina.projects.PackageCompilation.compile(PackageCompilation.java:114)
	at io.ballerina.projects.PackageCompilation.from(PackageCompilation.java:103)
	at io.ballerina.projects.PackageContext.getPackageCompilation(PackageContext.java:214)
	at io.ballerina.projects.Package.getCompilation(Package.java:141)
	at org.ballerinalang.langserver.workspace.BallerinaWorkspaceManager.waitAndGetPackageCompilation(BallerinaWorkspaceManager.java:271)
	at org.ballerinalang.langserver.util.LSClientUtil.chekAndRegisterCommands(LSClientUtil.java:78)
	at org.ballerinalang.langserver.BallerinaTextDocumentService.didChange(BallerinaTextDocumentService.java:556)
	at jdk.internal.reflect.GeneratedMethodAccessor78.invoke(Unknown Source)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
	at org.eclipse.lsp4j.jsonrpc.services.GenericEndpoint.lambda$null$0(GenericEndpoint.java:65)
	at org.eclipse.lsp4j.jsonrpc.services.GenericEndpoint.notify(GenericEndpoint.java:152)
	at org.eclipse.lsp4j.jsonrpc.RemoteEndpoint.handleNotification(RemoteEndpoint.java:220)
	at org.eclipse.lsp4j.jsonrpc.RemoteEndpoint.consume(RemoteEndpoint.java:187)
	at org.eclipse.lsp4j.jsonrpc.json.StreamMessageProducer.handleMessage(StreamMessageProducer.java:194)
	at org.eclipse.lsp4j.jsonrpc.json.StreamMessageProducer.listen(StreamMessageProducer.java:94)
	at org.eclipse.lsp4j.jsonrpc.json.ConcurrentMessageProcessor.run(ConcurrentMessageProcessor.java:113)
	at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)
	at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
	at java.base/java.lang.Thread.run(Thread.java:834)

Steps to reproduce:
See description

Affected Versions:
SL 2201 RC2

[github-actions]

This issue is NOT closed with a proper Reason/ label. Make sure to add proper reason label before closing. Please add or leave a comment with the proper reason label now.

      - Reason/EngineeringMistake - The issue occurred due to a mistake made in the past.
      - Reason/Regression - The issue has introduced a regression.
      - Reason/MultipleComponentInteraction - Issue occured due to interactions in multiple components.
      - Reason/Complex - Issue occurred due to complex scenario.
      - Reason/Invalid - Issue is invalid.
      - Reason/Other - None of the above cases.