[GROOVY-11026] NPE when checking compatibility of method reference

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 5.0.0-alpha-1
• Component/s: Static Type Checker
• Assignee: Eric Milles
• Reporter: Thodoris Sotiropoulos
• Created: 26/Apr/23 15:40
• Updated: 23/Aug/23 09:11
• Resolved: 29/Apr/23 14:52

Description

I have the following program

import java.util.function.*;
import java.util.List;

class Main {
  static final void test() {
        List<String> x = null;
        m(x::set);
  }

  static final <T, R> void m(BiFunction<T, R, R> y) {}

}

Actual behavior

BUG! exception in phase 'instruction selection' in source unit 'test.groovy' unexpected NullPointerException
        at org.codehaus.groovy.control.CompilationUnit$IPrimaryClassNodeOperation.doPhaseOperation(CompilationUnit.java:953)
        at org.codehaus.groovy.control.CompilationUnit.processPhaseOperations(CompilationUnit.java:694)
        at org.codehaus.groovy.control.CompilationUnit.compile(CompilationUnit.java:668)
        at org.codehaus.groovy.control.CompilationUnit.compile(CompilationUnit.java:649)
        at org.codehaus.groovy.tools.FileSystemCompiler.compile(FileSystemCompiler.java:311)
        at org.codehaus.groovy.tools.FileSystemCompiler.doCompilation(FileSystemCompiler.java:240)
        at org.codehaus.groovy.tools.FileSystemCompiler.commandLineCompile(FileSystemCompiler.java:165)
        at org.codehaus.groovy.tools.FileSystemCompiler.commandLineCompileWithErrorHandling(FileSystemCompiler.java:205)
        at org.codehaus.groovy.tools.FileSystemCompiler.main(FileSystemCompiler.java:189)
Caused by: java.lang.NullPointerException
        at org.codehaus.groovy.transform.stc.StaticTypeCheckingSupport.checkCompatibleAssignmentTypes(StaticTypeCheckingSupport.java:725)
        at org.codehaus.groovy.transform.stc.StaticTypeCheckingVisitor.lambda$visitMethodPointerExpression$25(StaticTypeCheckingVisitor.java:2504)
        at java.base/java.util.Optional.ifPresent(Optional.java:183)
        at org.codehaus.groovy.transform.stc.StaticTypeCheckingVisitor.visitMethodPointerExpression(StaticTypeCheckingVisitor.java:2496)
        at org.codehaus.groovy.ast.CodeVisitorSupport.visitMethodReferenceExpression(CodeVisitorSupport.java:319)
        at org.codehaus.groovy.ast.expr.MethodReferenceExpression.visit(MethodReferenceExpression.java:34)
        at org.codehaus.groovy.transform.stc.StaticTypeCheckingVisitor.visitMethodCallArguments(StaticTypeCheckingVisitor.java:2912)
        at org.codehaus.groovy.transform.stc.StaticTypeCheckingVisitor.visitStaticMethodCallExpression(StaticTypeCheckingVisitor.java:2820)
        at org.codehaus.groovy.ast.expr.StaticMethodCallExpression.visit(StaticMethodCallExpression.java:44)
        at org.codehaus.groovy.ast.CodeVisitorSupport.visitExpressionStatement(CodeVisitorSupport.java:117)
        at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitExpressionStatement(ClassCodeVisitorSupport.java:212)
        at org.codehaus.groovy.transform.stc.StaticTypeCheckingVisitor.visitExpressionStatement(StaticTypeCheckingVisitor.java:2217)
        at org.codehaus.groovy.ast.stmt.ExpressionStatement.visit(ExpressionStatement.java:41)
        at org.codehaus.groovy.ast.CodeVisitorSupport.visitBlockStatement(CodeVisitorSupport.java:86)
        at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitBlockStatement(ClassCodeVisitorSupport.java:175)
        at org.codehaus.groovy.ast.stmt.BlockStatement.visit(BlockStatement.java:72)
        at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitClassCodeContainer(ClassCodeVisitorSupport.java:139)
        at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitConstructorOrMethod(ClassCodeVisitorSupport.java:118)
        at org.codehaus.groovy.transform.stc.StaticTypeCheckingVisitor.lambda$visitConstructorOrMethod$28(StaticTypeCheckingVisitor.java:2681)
        at org.codehaus.groovy.transform.stc.StaticTypeCheckingVisitor.doWithTypeCheckingExtensions(StaticTypeCheckingVisitor.java:463)
        at org.codehaus.groovy.transform.stc.StaticTypeCheckingVisitor.visitConstructorOrMethod(StaticTypeCheckingVisitor.java:2681)
        at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitMethod(ClassCodeVisitorSupport.java:110)
        at org.codehaus.groovy.transform.stc.StaticTypeCheckingVisitor.startMethodInference(StaticTypeCheckingVisitor.java:2664)
        at org.codehaus.groovy.transform.stc.StaticTypeCheckingVisitor.visitMethod(StaticTypeCheckingVisitor.java:2643)
        at org.codehaus.groovy.transform.sc.StaticCompilationVisitor.visitConstructorOrMethod(StaticCompilationVisitor.java:189)
        at org.codehaus.groovy.transform.sc.StaticCompilationVisitor.visitMethod(StaticCompilationVisitor.java:204)
        at org.codehaus.groovy.ast.ClassNode.visitMethods(ClassNode.java:1144)
        at org.codehaus.groovy.ast.ClassNode.visitContents(ClassNode.java:1137)
        at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitClass(ClassCodeVisitorSupport.java:52)
        at org.codehaus.groovy.transform.stc.StaticTypeCheckingVisitor.lambda$visitClass$3(StaticTypeCheckingVisitor.java:499)
        at org.codehaus.groovy.transform.stc.StaticTypeCheckingVisitor.doWithTypeCheckingExtensions(StaticTypeCheckingVisitor.java:463)
        at org.codehaus.groovy.transform.stc.StaticTypeCheckingVisitor.visitClass(StaticTypeCheckingVisitor.java:499)
        at org.codehaus.groovy.transform.sc.StaticCompilationVisitor.visitClass(StaticCompilationVisitor.java:151)
        at org.codehaus.groovy.transform.sc.StaticCompileTransformation.visit(StaticCompileTransformation.java:68)
        at org.codehaus.groovy.control.customizers.ASTTransformationCustomizer.call(ASTTransformationCustomizer.groovy:303)
        at org.codehaus.groovy.control.CompilationUnit$IPrimaryClassNodeOperation.doPhaseOperation(CompilationUnit.java:948)
        ... 8 more

Compile succssfully

Notes

Tested against master (commit: 8346e3406ed51dd071a2d31792d3fbad543585a7)