Package javassist.compiler

Class CodeGen

java.lang.Object

javassist.compiler.ast.Visitor

javassist.compiler.CodeGen

All Implemented Interfaces:

Opcode, TokenId

Direct Known Subclasses:

MemberCodeGen

public abstract class CodeGen
extends Visitor
implements Opcode, TokenId

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected static class	CodeGen.ReturnHook	doit() in ReturnHook is called from atReturn().

Field Summary

Fields

Modifier and Type	Field	Description
protected int	arrayDim
(package private) static final int[]	binOp
protected List<Integer>	breakList
protected Bytecode	bytecode
private static final int[]	castOp
protected String	className
protected List<Integer>	continueList
protected int	exprType
protected boolean	hasReturned	true if the last visited node is a return statement.
private static final int[]	ifOp
private static final int[]	ifOp2
boolean	inStaticMethod	Must be true if compilation is for a static method.
(package private) static final String	javaLangObject
(package private) static final String	javaLangString
(package private) static final String	jvmJavaLangObject
(package private) static final String	jvmJavaLangString
private static final int	P_DOUBLE
private static final int	P_FLOAT
private static final int	P_INT
private static final int	P_LONG
private static final int	P_OTHER
protected CodeGen.ReturnHook	returnHooks
private int	tempVar
(package private) TypeChecker	typeChecker

Fields inherited from interface javassist.bytecode.Opcode

AALOAD, AASTORE, ACONST_NULL, ALOAD, ALOAD_0, ALOAD_1, ALOAD_2, ALOAD_3, ANEWARRAY, ARETURN, ARRAYLENGTH, ASTORE, ASTORE_0, ASTORE_1, ASTORE_2, ASTORE_3, ATHROW, BALOAD, BASTORE, BIPUSH, CALOAD, CASTORE, CHECKCAST, D2F, D2I, D2L, DADD, DALOAD, DASTORE, DCMPG, DCMPL, DCONST_0, DCONST_1, DDIV, DLOAD, DLOAD_0, DLOAD_1, DLOAD_2, DLOAD_3, DMUL, DNEG, DREM, DRETURN, DSTORE, DSTORE_0, DSTORE_1, DSTORE_2, DSTORE_3, DSUB, DUP, DUP_X1, DUP_X2, DUP2, DUP2_X1, DUP2_X2, F2D, F2I, F2L, FADD, FALOAD, FASTORE, FCMPG, FCMPL, FCONST_0, FCONST_1, FCONST_2, FDIV, FLOAD, FLOAD_0, FLOAD_1, FLOAD_2, FLOAD_3, FMUL, FNEG, FREM, FRETURN, FSTORE, FSTORE_0, FSTORE_1, FSTORE_2, FSTORE_3, FSUB, GETFIELD, GETSTATIC, GOTO, GOTO_W, I2B, I2C, I2D, I2F, I2L, I2S, IADD, IALOAD, IAND, IASTORE, ICONST_0, ICONST_1, ICONST_2, ICONST_3, ICONST_4, ICONST_5, ICONST_M1, IDIV, IF_ACMPEQ, IF_ACMPNE, IF_ICMPEQ, IF_ICMPGE, IF_ICMPGT, IF_ICMPLE, IF_ICMPLT, IF_ICMPNE, IFEQ, IFGE, IFGT, IFLE, IFLT, IFNE, IFNONNULL, IFNULL, IINC, ILOAD, ILOAD_0, ILOAD_1, ILOAD_2, ILOAD_3, IMUL, INEG, INSTANCEOF, INVOKEDYNAMIC, INVOKEINTERFACE, INVOKESPECIAL, INVOKESTATIC, INVOKEVIRTUAL, IOR, IREM, IRETURN, ISHL, ISHR, ISTORE, ISTORE_0, ISTORE_1, ISTORE_2, ISTORE_3, ISUB, IUSHR, IXOR, JSR, JSR_W, L2D, L2F, L2I, LADD, LALOAD, LAND, LASTORE, LCMP, LCONST_0, LCONST_1, LDC, LDC_W, LDC2_W, LDIV, LLOAD, LLOAD_0, LLOAD_1, LLOAD_2, LLOAD_3, LMUL, LNEG, LOOKUPSWITCH, LOR, LREM, LRETURN, LSHL, LSHR, LSTORE, LSTORE_0, LSTORE_1, LSTORE_2, LSTORE_3, LSUB, LUSHR, LXOR, MONITORENTER, MONITOREXIT, MULTIANEWARRAY, NEW, NEWARRAY, NOP, POP, POP2, PUTFIELD, PUTSTATIC, RET, RETURN, SALOAD, SASTORE, SIPUSH, STACK_GROW, SWAP, T_BOOLEAN, T_BYTE, T_CHAR, T_DOUBLE, T_FLOAT, T_INT, T_LONG, T_SHORT, TABLESWITCH, WIDE

Fields inherited from interface javassist.compiler.TokenId

ABSTRACT, AND_E, ANDAND, ARRAY, ARSHIFT, ARSHIFT_E, assignOps, BadToken, BLOCK, BOOLEAN, BREAK, BYTE, CALL, CASE, CATCH, CHAR, CharConstant, CLASS, CONST, CONTINUE, DECL, DEFAULT, DIV_E, DO, DOUBLE, DoubleConstant, ELSE, EQ, EXOR_E, EXPR, EXTENDS, FALSE, FINAL, FINALLY, FLOAT, FloatConstant, FOR, GE, GOTO, Identifier, IF, IMPLEMENTS, IMPORT, INSTANCEOF, INT, IntConstant, INTERFACE, LABEL, LE, LONG, LongConstant, LSHIFT, LSHIFT_E, MEMBER, MINUS_E, MINUSMINUS, MOD_E, MUL_E, NATIVE, NEQ, NEW, NULL, opNames, OR_E, OROR, PACKAGE, PLUS_E, PLUSPLUS, PRIVATE, PROTECTED, PUBLIC, RETURN, RSHIFT, RSHIFT_E, SHORT, STATIC, STRICT, StringL, SUPER, SWITCH, SYNCHRONIZED, THIS, THROW, THROWS, TRANSIENT, TRUE, TRY, VOID, VOLATILE, WHILE

Constructor Summary

Constructors

Constructor	Description
CodeGen(Bytecode b)

Method Summary

Modifier and Type	Method	Description
protected void	arrayAccess(ASTree array, ASTree index)
private void	atArithBinExpr(Expr expr, int token, int index, int type1)
private void	atArrayAssign(Expr expr, int op, Expr array, ASTree right, boolean doDup)
abstract void	atArrayInit(ArrayInit init)
void	atArrayPlusPlus(int token, boolean isPost, Expr expr, boolean doDup)
void	atArrayRead(ASTree array, ASTree index)
protected abstract void	atArrayVariableAssign(ArrayInit init, int varType, int varArray, String varClass)
protected void	atAssignCore(Expr expr, int op, ASTree right, int type, int dim, String cname)
void	atAssignExpr(AssignExpr expr)
protected void	atAssignExpr(AssignExpr expr, boolean doDup)
void	atASTList(ASTList n)
void	atBinExpr(BinExpr expr)
private void	atBreakStmnt(Stmnt st, boolean notCont)
abstract void	atCallExpr(CallExpr expr)
void	atCastExpr(CastExpr expr)
void	atClassObject(Expr expr)
protected void	atClassObject2(String cname)
void	atCondExpr(CondExpr expr)
void	atDeclarator(Declarator d)
void	atDoubleConst(DoubleConst d)
void	atExpr(Expr expr)
protected abstract void	atFieldAssign(Expr expr, int op, ASTree left, ASTree right, boolean doDup)
void	atFieldDecl(FieldDecl field)
protected abstract void	atFieldPlusPlus(int token, boolean isPost, ASTree oprand, Expr expr, boolean doDup)
protected abstract void	atFieldRead(ASTree expr)
private void	atForStmnt(Stmnt st)
private void	atIfStmnt(Stmnt st)
void	atInstanceOfExpr(InstanceOfExpr expr)
void	atIntConst(IntConst i)
void	atKeyword(Keyword k)
abstract void	atMember(Member n)
void	atMethodBody(Stmnt s, boolean isCons, boolean isVoid)
void	atMethodDecl(MethodDecl method)
abstract void	atNewExpr(NewExpr n)
(package private) void	atNumCastExpr(int srcType, int destType)
void	atPair(Pair n)
private void	atPlusPlus(int token, ASTree oprand, Expr expr, boolean doDup)
protected void	atPlusPlusCore(int dup_code, boolean doDup, int token, boolean isPost, Expr expr)
protected void	atReturnStmnt(Stmnt st)
protected final void	atReturnStmnt2(ASTree result)
void	atStmnt(Stmnt st)
private void	atStringConcatExpr(Expr expr, int type1, int dim1, String cname1)
void	atStringL(StringL s)
private void	atStringPlusEq(Expr expr, int type, int dim, String cname, ASTree right)
private void	atSwitchStmnt(Stmnt st)
void	atSymbol(Symbol n)
private void	atSyncStmnt(Stmnt st)
private void	atThrowStmnt(Stmnt st)
protected void	atTryStmnt(Stmnt st)
void	atVariable(Variable v)
private void	atVariableAssign(Expr expr, int op, Variable var, Declarator d, ASTree right, boolean doDup)
private void	atWhileStmnt(Stmnt st, boolean notDo)
protected static void	badAssign(Expr expr)
protected static void	badType(Expr expr)
protected static void	badTypes(Expr expr)
private boolean	booleanExpr(boolean branchIf, ASTree expr)
private String	checkCastExpr(CastExpr expr, String name)
private void	compareExpr(boolean branchIf, int token, int type1, BinExpr expr)
boolean	compileBooleanExpr(boolean branchIf, ASTree expr)
void	compileExpr(ASTree expr)
private int	compileOprands(BinExpr expr)
private int	computeLabel(ASTree expr)
private int	computeStringLabel(ASTree expr, int tmpVar, List<Integer> gotoDefaults)
private void	convertOprandTypes(int type1, int type2, Expr expr)
private void	convToString(int type, int dim)
void	doTypeCheck(ASTree expr)
protected static void	fatal()
protected static int	getArrayReadOp(int type, int dim)
protected static int	getArrayWriteOp(int type, int dim)
(package private) static int	getCompOperator(ASTree expr)
private static int	getListSize(List<Integer> list)
protected int	getLocalVar(Declarator d)
int	getMaxLocals()
protected abstract String	getSuperName()	Returns the JVM-internal representation of this super class name.
protected int	getTempVar()	Returns a local variable that single or double words can be stored in.
protected abstract String	getThisName()	Returns the JVM-internal representation of this class name.
protected void	incMaxLocals(int size)
protected abstract void	insertDefaultSuperCall()
private boolean	invalidDim(int srcType, int srcDim, String srcClass, int destType, int destDim, String destClass, boolean isCast)
static boolean	is2word(int type, int dim)
private static boolean	isAlwaysBranch(ASTree expr, boolean branchIf)
(package private) static boolean	isP_INT(int type)
private static boolean	isPlusPlusExpr(ASTree expr)
protected static boolean	isRefType(int type)
(package private) static int	lookupBinOp(int token)
private boolean	needsSuperCall(Stmnt body)
protected void	patchGoto(List<Integer> list, int targetPc)
protected abstract String	resolveClassName(String jvmClassName)
protected abstract String	resolveClassName(ASTList name)
(package private) static boolean	rightIsStrong(int type1, int type2)
void	setMaxLocals(int n)
void	setTypeChecker(TypeChecker checker)
protected static String	toJvmArrayName(String name, int dim)
protected static String	toJvmTypeName(int type, int dim)
private static int	typePrecedence(int type)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

javaLangObject

static final String javaLangObject

See Also:

• Constant Field Values

jvmJavaLangObject

static final String jvmJavaLangObject

See Also:

• Constant Field Values

javaLangString

static final String javaLangString

See Also:

• Constant Field Values

jvmJavaLangString

static final String jvmJavaLangString

See Also:

• Constant Field Values

bytecode

protected Bytecode bytecode

tempVar

private int tempVar

typeChecker

TypeChecker typeChecker

hasReturned

protected boolean hasReturned

true if the last visited node is a return statement.

inStaticMethod

public boolean inStaticMethod

Must be true if compilation is for a static method.

breakList

protected List<Integer> breakList

continueList

protected List<Integer> continueList

returnHooks

protected CodeGen.ReturnHook returnHooks

exprType

protected int exprType

arrayDim

protected int arrayDim

className

protected String className

binOp

static final int[] binOp

ifOp

private static final int[] ifOp

ifOp2

private static final int[] ifOp2

P_DOUBLE

private static final int P_DOUBLE

See Also:

• Constant Field Values

P_FLOAT

private static final int P_FLOAT

See Also:

• Constant Field Values

P_LONG

private static final int P_LONG

See Also:

• Constant Field Values

P_INT

private static final int P_INT

See Also:

• Constant Field Values

P_OTHER

private static final int P_OTHER

See Also:

• Constant Field Values

castOp

private static final int[] castOp

Constructor Details

CodeGen

public CodeGen(Bytecode b)

Method Details

setTypeChecker

public void setTypeChecker(TypeChecker checker)

fatal

protected static void fatal()
                     throws CompileError

Throws:

CompileError

is2word

public static boolean is2word(int type,
 int dim)

getMaxLocals

public int getMaxLocals()

setMaxLocals

public void setMaxLocals(int n)

incMaxLocals

protected void incMaxLocals(int size)

getTempVar

protected int getTempVar()

Returns a local variable that single or double words can be stored in.

getLocalVar

protected int getLocalVar(Declarator d)

getThisName

protected abstract String getThisName()

Returns the JVM-internal representation of this class name.

getSuperName

protected abstract String getSuperName()
                                throws CompileError

Returns the JVM-internal representation of this super class name.

Throws:

CompileError

resolveClassName

protected abstract String resolveClassName(ASTList name)
                                    throws CompileError

Throws:

CompileError

resolveClassName

protected abstract String resolveClassName(String jvmClassName)
                                    throws CompileError

Throws:

CompileError

toJvmArrayName

protected static String toJvmArrayName(String name,
 int dim)

Parameters:

name - the JVM-internal representation. name is not exapnded to java.lang.*.

toJvmTypeName

protected static String toJvmTypeName(int type,
 int dim)

compileExpr

public void compileExpr(ASTree expr)
                 throws CompileError

Throws:

CompileError

compileBooleanExpr

public boolean compileBooleanExpr(boolean branchIf,
 ASTree expr)
                           throws CompileError

Throws:

CompileError

doTypeCheck

public void doTypeCheck(ASTree expr)
                 throws CompileError

Throws:

CompileError

atASTList

public void atASTList(ASTList n)
               throws CompileError

Overrides:

atASTList in class Visitor

Throws:

CompileError

atPair

public void atPair(Pair n)
            throws CompileError

Overrides:

atPair in class Visitor

Throws:

CompileError

atSymbol

public void atSymbol(Symbol n)
              throws CompileError

Overrides:

atSymbol in class Visitor

Throws:

CompileError

atFieldDecl

public void atFieldDecl(FieldDecl field)
                 throws CompileError

Overrides:

atFieldDecl in class Visitor

Throws:

CompileError

atMethodDecl

public void atMethodDecl(MethodDecl method)
                  throws CompileError

Overrides:

atMethodDecl in class Visitor

Throws:

CompileError

atMethodBody

public void atMethodBody(Stmnt s,
 boolean isCons,
 boolean isVoid)
                  throws CompileError

Parameters:

isCons - true if super() must be called. false if the method is a class initializer.

Throws:

CompileError

needsSuperCall

private boolean needsSuperCall(Stmnt body)
                        throws CompileError

Throws:

CompileError

insertDefaultSuperCall

protected abstract void insertDefaultSuperCall()
                                        throws CompileError

Throws:

CompileError

atStmnt

public void atStmnt(Stmnt st)
             throws CompileError

Overrides:

atStmnt in class Visitor

Throws:

CompileError

atIfStmnt

private void atIfStmnt(Stmnt st)
                throws CompileError

Throws:

CompileError

atWhileStmnt

private void atWhileStmnt(Stmnt st,
 boolean notDo)
                   throws CompileError

Throws:

CompileError

patchGoto

protected void patchGoto(List<Integer> list,
 int targetPc)

atForStmnt

private void atForStmnt(Stmnt st)
                 throws CompileError

Throws:

CompileError

atSwitchStmnt

private void atSwitchStmnt(Stmnt st)
                    throws CompileError

Throws:

CompileError

computeLabel

private int computeLabel(ASTree expr)
                  throws CompileError

Throws:

CompileError

computeStringLabel

private int computeStringLabel(ASTree expr,
 int tmpVar,
 List<Integer> gotoDefaults)
                        throws CompileError

Throws:

CompileError

atBreakStmnt

private void atBreakStmnt(Stmnt st,
 boolean notCont)
                   throws CompileError

Throws:

CompileError

atReturnStmnt

protected void atReturnStmnt(Stmnt st)
                      throws CompileError

Throws:

CompileError

atReturnStmnt2

protected final void atReturnStmnt2(ASTree result)
                             throws CompileError

Throws:

CompileError

atThrowStmnt

private void atThrowStmnt(Stmnt st)
                   throws CompileError

Throws:

CompileError

atTryStmnt

protected void atTryStmnt(Stmnt st)
                   throws CompileError

Throws:

CompileError

atSyncStmnt

private void atSyncStmnt(Stmnt st)
                  throws CompileError

Throws:

CompileError

getListSize

private static int getListSize(List<Integer> list)

isPlusPlusExpr

private static boolean isPlusPlusExpr(ASTree expr)

atDeclarator

public void atDeclarator(Declarator d)
                  throws CompileError

Overrides:

atDeclarator in class Visitor

Throws:

CompileError

atNewExpr

public abstract void atNewExpr(NewExpr n)
                        throws CompileError

Overrides:

atNewExpr in class Visitor

Throws:

CompileError

atArrayInit

public abstract void atArrayInit(ArrayInit init)
                          throws CompileError

Overrides:

atArrayInit in class Visitor

Throws:

CompileError

atAssignExpr

public void atAssignExpr(AssignExpr expr)
                  throws CompileError

Overrides:

atAssignExpr in class Visitor

Throws:

CompileError

atAssignExpr

protected void atAssignExpr(AssignExpr expr,
 boolean doDup)
                     throws CompileError

Throws:

CompileError

badAssign

protected static void badAssign(Expr expr)
                         throws CompileError

Throws:

CompileError

atVariableAssign

private void atVariableAssign(Expr expr,
 int op,
 Variable var,
 Declarator d,
 ASTree right,
 boolean doDup)
                       throws CompileError

Throws:

CompileError

atArrayVariableAssign

protected abstract void atArrayVariableAssign(ArrayInit init,
 int varType,
 int varArray,
 String varClass)
                                       throws CompileError

Throws:

CompileError

atArrayAssign

private void atArrayAssign(Expr expr,
 int op,
 Expr array,
 ASTree right,
 boolean doDup)
                    throws CompileError

Throws:

CompileError

atFieldAssign

protected abstract void atFieldAssign(Expr expr,
 int op,
 ASTree left,
 ASTree right,
 boolean doDup)
                               throws CompileError

Throws:

CompileError

atAssignCore

protected void atAssignCore(Expr expr,
 int op,
 ASTree right,
 int type,
 int dim,
 String cname)
                     throws CompileError

Throws:

CompileError

atStringPlusEq

private void atStringPlusEq(Expr expr,
 int type,
 int dim,
 String cname,
 ASTree right)
                     throws CompileError

Throws:

CompileError

invalidDim

private boolean invalidDim(int srcType,
 int srcDim,
 String srcClass,
 int destType,
 int destDim,
 String destClass,
 boolean isCast)

atCondExpr

public void atCondExpr(CondExpr expr)
                throws CompileError

Overrides:

atCondExpr in class Visitor

Throws:

CompileError

lookupBinOp

static int lookupBinOp(int token)

atBinExpr

public void atBinExpr(BinExpr expr)
               throws CompileError

Overrides:

atBinExpr in class Visitor

Throws:

CompileError

atArithBinExpr

private void atArithBinExpr(Expr expr,
 int token,
 int index,
 int type1)
                     throws CompileError

Throws:

CompileError

atStringConcatExpr

private void atStringConcatExpr(Expr expr,
 int type1,
 int dim1,
 String cname1)
                         throws CompileError

Throws:

CompileError

convToString

private void convToString(int type,
 int dim)
                   throws CompileError

Throws:

CompileError

booleanExpr

private boolean booleanExpr(boolean branchIf,
 ASTree expr)
                     throws CompileError

Throws:

CompileError

isAlwaysBranch

private static boolean isAlwaysBranch(ASTree expr,
 boolean branchIf)

getCompOperator

static int getCompOperator(ASTree expr)
                    throws CompileError

Throws:

CompileError

compileOprands

private int compileOprands(BinExpr expr)
                    throws CompileError

Throws:

CompileError

compareExpr

private void compareExpr(boolean branchIf,
 int token,
 int type1,
 BinExpr expr)
                  throws CompileError

Throws:

CompileError

badTypes

protected static void badTypes(Expr expr)
                        throws CompileError

Throws:

CompileError

isRefType

protected static boolean isRefType(int type)

typePrecedence

private static int typePrecedence(int type)

isP_INT

static boolean isP_INT(int type)

rightIsStrong

static boolean rightIsStrong(int type1,
 int type2)

convertOprandTypes

private void convertOprandTypes(int type1,
 int type2,
 Expr expr)
                         throws CompileError

Throws:

CompileError

atCastExpr

public void atCastExpr(CastExpr expr)
                throws CompileError

Overrides:

atCastExpr in class Visitor

Throws:

CompileError

atInstanceOfExpr

public void atInstanceOfExpr(InstanceOfExpr expr)
                      throws CompileError

Overrides:

atInstanceOfExpr in class Visitor

Throws:

CompileError

checkCastExpr

private String checkCastExpr(CastExpr expr,
 String name)
                      throws CompileError

Throws:

CompileError

atNumCastExpr

void atNumCastExpr(int srcType,
 int destType)
            throws CompileError

Throws:

CompileError

atExpr

public void atExpr(Expr expr)
            throws CompileError

Overrides:

atExpr in class Visitor

Throws:

CompileError

badType

protected static void badType(Expr expr)
                       throws CompileError

Throws:

CompileError

atCallExpr

public abstract void atCallExpr(CallExpr expr)
                         throws CompileError

Overrides:

atCallExpr in class Visitor

Throws:

CompileError

atFieldRead

protected abstract void atFieldRead(ASTree expr)
                             throws CompileError

Throws:

CompileError

atClassObject

public void atClassObject(Expr expr)
                   throws CompileError

Throws:

CompileError

atClassObject2

protected void atClassObject2(String cname)
                       throws CompileError

Throws:

CompileError

atArrayRead

public void atArrayRead(ASTree array,
 ASTree index)
                 throws CompileError

Throws:

CompileError

arrayAccess

protected void arrayAccess(ASTree array,
 ASTree index)
                    throws CompileError

Throws:

CompileError

getArrayReadOp

protected static int getArrayReadOp(int type,
 int dim)

getArrayWriteOp

protected static int getArrayWriteOp(int type,
 int dim)

atPlusPlus

private void atPlusPlus(int token,
 ASTree oprand,
 Expr expr,
 boolean doDup)
                 throws CompileError

Throws:

CompileError

atArrayPlusPlus

public void atArrayPlusPlus(int token,
 boolean isPost,
 Expr expr,
 boolean doDup)
                     throws CompileError

Throws:

CompileError

atPlusPlusCore

protected void atPlusPlusCore(int dup_code,
 boolean doDup,
 int token,
 boolean isPost,
 Expr expr)
                       throws CompileError

Throws:

CompileError

atFieldPlusPlus

protected abstract void atFieldPlusPlus(int token,
 boolean isPost,
 ASTree oprand,
 Expr expr,
 boolean doDup)
                                 throws CompileError

Throws:

CompileError

atMember

public abstract void atMember(Member n)
                       throws CompileError

Overrides:

atMember in class Visitor

Throws:

CompileError

atVariable

public void atVariable(Variable v)
                throws CompileError

Overrides:

atVariable in class Visitor

Throws:

CompileError

atKeyword

public void atKeyword(Keyword k)
               throws CompileError

Overrides:

atKeyword in class Visitor

Throws:

CompileError

atStringL

public void atStringL(StringL s)
               throws CompileError

Overrides:

atStringL in class Visitor

Throws:

CompileError

atIntConst

public void atIntConst(IntConst i)
                throws CompileError

Overrides:

atIntConst in class Visitor

Throws:

CompileError

atDoubleConst

public void atDoubleConst(DoubleConst d)
                   throws CompileError

Overrides:

atDoubleConst in class Visitor

Throws:

CompileError