[GROOVY-7021] CompileStatic on templated classes with multiple template constraints

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.3.4
• Fix Version/s: 2.4.0-rc-1
• Component/s: Static Type Checker
• Labels: CompileStatic
• Environment: Windows 7, jdk 1.8.0_20 64-bit
• Assignee: Unassigned
• Reporter: Brad Miller
• Created: 12/Aug/14 13:10
• Updated: 28/Dec/14 10:52
• Resolved: 28/Dec/14 10:52

Description

A @CompileStatic compilation of the below file

package myBugReport

import groovy.transform.CompileStatic

@CompileStatic
abstract class MyCompileStaticBugG<TertiaryT extends TertiaryG> {
  TertiaryT myProp

  // workaround: if @CompileDynamic this method, it compiles just fine.  But this is the bug - it should @CompileStatic...
  void load() {
      if (myProp == null)
      {
        myProp = loadProp()
      }
    }

    abstract TertiaryT loadProp()
}

@CompileStatic
abstract class PrimaryG {}

@CompileStatic
abstract class SecondaryG<PrimaryT extends PrimaryG> {}

@CompileStatic
abstract class TertiaryG<PrimaryT extends PrimaryG, SecondaryT extends SecondaryG<PrimaryT>> {}

results in the following exception:

Error:Groovyc: java.lang.ArrayIndexOutOfBoundsException: 1
	at org.codehaus.groovy.ast.tools.GenericsUtils.extractPlaceholders(GenericsUtils.java:143)
	at org.codehaus.groovy.ast.tools.GenericsUtils.parameterizeType(GenericsUtils.java:219)
	at org.codehaus.groovy.transform.stc.StaticTypeCheckingVisitor.visitBinaryExpression(StaticTypeCheckingVisitor.java:549)
	at org.codehaus.groovy.ast.expr.BinaryExpression.visit(BinaryExpression.java:49)
	at org.codehaus.groovy.ast.CodeVisitorSupport.visitExpressionStatement(CodeVisitorSupport.java:69)
	at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitExpressionStatement(ClassCodeVisitorSupport.java:193)
	at org.codehaus.groovy.ast.stmt.ExpressionStatement.visit(ExpressionStatement.java:40)
	at org.codehaus.groovy.ast.CodeVisitorSupport.visitBlockStatement(CodeVisitorSupport.java:35)
	at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitBlockStatement(ClassCodeVisitorSupport.java:163)
	at org.codehaus.groovy.ast.stmt.BlockStatement.visit(BlockStatement.java:69)
	at org.codehaus.groovy.transform.stc.StaticTypeCheckingVisitor.visitIfElse(StaticTypeCheckingVisitor.java:2948)
	at org.codehaus.groovy.ast.stmt.IfStatement.visit(IfStatement.java:41)
	at org.codehaus.groovy.ast.CodeVisitorSupport.visitBlockStatement(CodeVisitorSupport.java:35)
	at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitBlockStatement(ClassCodeVisitorSupport.java:163)
	at org.codehaus.groovy.ast.stmt.BlockStatement.visit(BlockStatement.java:69)
	at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitClassCodeContainer(ClassCodeVisitorSupport.java:101)
	at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitConstructorOrMethod(ClassCodeVisitorSupport.java:112)
	at org.codehaus.groovy.transform.stc.StaticTypeCheckingVisitor.visitConstructorOrMethod(StaticTypeCheckingVisitor.java:1614)
	at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitMethod(ClassCodeVisitorSupport.java:123)
	at org.codehaus.groovy.transform.stc.StaticTypeCheckingVisitor.startMethodInference(StaticTypeCheckingVisitor.java:1933)
	at org.codehaus.groovy.transform.stc.StaticTypeCheckingVisitor.visitMethod(StaticTypeCheckingVisitor.java:1892)
	at org.codehaus.groovy.transform.sc.StaticCompilationVisitor.visitMethod(StaticCompilationVisitor.java:144)
	at org.codehaus.groovy.ast.ClassNode.visitContents(ClassNode.java:1063)
	at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitClass(ClassCodeVisitorSupport.java:50)
	at org.codehaus.groovy.transform.stc.StaticTypeCheckingVisitor.visitClass(StaticTypeCheckingVisitor.java:240)
	at org.codehaus.groovy.transform.sc.StaticCompilationVisitor.visitClass(StaticCompilationVisitor.java:110)
	at org.codehaus.groovy.transform.sc.StaticCompileTransformation.visit(StaticCompileTransformation.java:61)
	at org.codehaus.groovy.transform.ASTTransformationVisitor.visitClass(ASTTransformationVisitor.java:132)
	at org.codehaus.groovy.transform.ASTTransformationVisitor$2.call(ASTTransformationVisitor.java:176)
	at org.codehaus.groovy.control.CompilationUnit.applyToPrimaryClassNodes(CompilationUnit.java:1047)
	at org.codehaus.groovy.control.CompilationUnit.doPhaseOperation(CompilationUnit.java:583)
	at org.codehaus.groovy.control.CompilationUnit.processPhaseOperations(CompilationUnit.java:561)
	at org.codehaus.groovy.control.CompilationUnit.compile(CompilationUnit.java:538)
	at org.jetbrains.groovy.compiler.rt.GroovyCompilerWrapper.compile(GroovyCompilerWrapper.java:54)
	at org.jetbrains.groovy.compiler.rt.DependentGroovycRunner.runGroovyc(DependentGroovycRunner.java:87)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:483)
	at org.jetbrains.groovy.compiler.rt.GroovycRunner.main(GroovycRunner.java:100)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:483)
	at com.intellij.rt.execution.CommandLineWrapper.main(CommandLineWrapper.java:121)

Unfortunately, the exception gives no clue as to what is wrong in the code (the stacktrace does not reference where the error occurs), so it is a fairly painful bug. I narrowed it down to the 'load' method in the above simplified version of the code: if I add the @CompileDynamic annotation to the 'load' method, the exception goes away.

Groovy should be able to @CompileStatic, as the equivalent Java code compiles just fine (equivalent java is also included in the zip file).