[GROOVY-11020] NullPointerException in instruction selection when calling parameterized function whose type parameter has an upper bound corresponding to a SAM type

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 3.0.18, 4.0.12
• Component/s: Static Type Checker
• Assignee: Eric Milles
• Reporter: Thodoris Sotiropoulos
• Created: 19/Apr/23 09:15
• Updated: 23/Aug/23 09:07
• Resolved: 19/Apr/23 17:11

Description

I have the following code

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

class Main {
  static final void test(ArrayDeque<String> y) {
    
    m(y::addFirst);
  }

  static <C extends Consumer<String>> void m(C cl) {}
}

Actual behavior

The compiler crashes with the following stacktrace:

>>> a serious error occurred: BUG! exception in phase 'instruction selection' in source unit 'Main.groovy' unexpected NullPointerException
>>> stacktrace:
BUG! exception in phase 'instruction selection' in source unit 'Main.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.ast.tools.GenericsUtils.parameterizeSAM(GenericsUtils.java:974)
        at org.codehaus.groovy.transform.stc.StaticTypeCheckingVisitor.inferClosureParameterTypes(StaticTypeCheckingVisitor.java:3110)
        at org.codehaus.groovy.transform.stc.StaticTypeCheckingVisitor.visitMethodCallArguments(StaticTypeCheckingVisitor.java:2904)
        at org.codehaus.groovy.transform.stc.StaticTypeCheckingVisitor.visitStaticMethodCallExpression(StaticTypeCheckingVisitor.java:2819)
        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$28(StaticTypeCheckingVisitor.java:2680)
        at org.codehaus.groovy.transform.stc.StaticTypeCheckingVisitor.doWithTypeCheckingExtensions(StaticTypeCheckingVisitor.java:463)
        at org.codehaus.groovy.transform.stc.StaticTypeCheckingVisitor.visitConstructorOrMethod(StaticTypeCheckingVisitor.java:2680)
        at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitMethod(ClassCodeVisitorSupport.java:110)
        at org.codehaus.groovy.transform.stc.StaticTypeCheckingVisitor.startMethodInference(StaticTypeCheckingVisitor.java:2663)
        at org.codehaus.groovy.transform.stc.StaticTypeCheckingVisitor.visitMethod(StaticTypeCheckingVisitor.java:2642)
        at org.codehaus.groovy.transform.sc.StaticCompilationVisitor.visitConstructorOrMethod(StaticCompilationVisitor.java:189)
        at org.codehaus.groovy.transform.sc.StaticCompilationVisitor.visitMethod(StaticCompilationVisitor.java:204)
        at org.codehaus.groovy.ast.ClassNode.visitMethods(ClassNode.java:1144)
        at org.codehaus.groovy.ast.ClassNode.visitContents(ClassNode.java:1137)
        at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitClass(ClassCodeVisitorSupport.java:52)
        at org.codehaus.groovy.transform.stc.StaticTypeCheckingVisitor.lambda$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

Expected behavior

Compile successfully

Notes

Tested against master (commit: 61f445cf4b1099eb25f770cc0685efb10783b8f1)

Test case adapted from a program that uses the apache-commons-collections lib:

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

class Main {
  static final void test(Iterator<String> x,
                         ArrayDeque<String> y) {
    
    org.apache.commons.collections4.CollectionUtils.forAllButLastDo(x, y::addFirst);
  }

}