//
// Copyright (c) 2006, Brian Frank and Andy Frank
// Licensed under the Academic Free License version 3.0
//
// History:
// 2 Dec 05 Brian Frank Creation
// 17 Sep 06 Brian Frank Ported from Java to Fan
//
**
** CheckErrors walks the tree of statements and expressions looking
** for errors the compiler can detect such as invalid type usage. We
** attempt to leave all the error reporting to this step, so that we
** can batch report as many errors as possible.
**
** Since CheckErrors already performs a full tree walk down to each leaf
** expression, we also do a couple of other AST decorations in this step:
** 1) add temp local for field assignments like return ++x
** 2) add temp local for returns inside protected region
** 3) check for field accessor optimization
** 4) check for field storage requirements
** 5) add implicit cast when assigning Obj to non-Obj
**
class CheckErrors : CompilerStep
{
//////////////////////////////////////////////////////////////////////////
// Constructor
//////////////////////////////////////////////////////////////////////////
new make(Compiler compiler)
: super(compiler)
{
}
//////////////////////////////////////////////////////////////////////////
// Run
//////////////////////////////////////////////////////////////////////////
override Void run()
{
log.debug("CheckErrors")
walk(types, VisitDepth.expr)
bombIfErr
}
//////////////////////////////////////////////////////////////////////////
// TypeDef
//////////////////////////////////////////////////////////////////////////
override Void visitTypeDef(TypeDef t)
{
// check type flags
checkTypeFlags(t)
// check for abstract slots in concrete class
checkAbstractSlots(t)
// check for const slots in const class
checkConstType(t)
// check some knuckle head doesn't override type
if (t.slotDef("type") != null && !compiler.isSys)
err("Cannot override Obj.type() knuckle head", t.slotDef("type").location)
}
private Void checkTypeFlags(TypeDef t)
{
flags := t.flags
loc := t.location
// these modifiers are never allowed on a type
if (flags & FConst.Ctor != 0) err("Cannot use 'new' modifier on type", loc)
if (flags & FConst.Native != 0) err("Cannot use 'native' modifier on type", loc)
if (flags & Parser.Once != 0) err("Cannot use 'once' modifier on type", loc)
if (flags & FConst.Override != 0) err("Cannot use 'override' modifier on type", loc)
if (flags & FConst.Private != 0) err("Cannot use 'private' modifier on type", loc)
if (flags & FConst.Protected != 0) err("Cannot use 'protected' modifier on type", loc)
if (flags & FConst.Static != 0) err("Cannot use 'static' modifier on type", loc)
if (flags & FConst.Virtual != 0) err("Cannot use 'virtual' modifier on type", loc)
if (flags & Parser.Readonly != 0) err("Cannot use 'readonly' modifier on type", loc)
// check invalid protection combinations
checkProtectionFlags(flags, loc)
// check abstract and final
if ((flags & FConst.Abstract != 0) && (flags & FConst.Final != 0))
err("Invalid combination of 'abstract' and 'final' modifiers", loc)
}
private Void checkAbstractSlots(TypeDef t)
{
// if already abstract, nothing to check
if (t.isAbstract) return
errForDef := false
closure := |CSlot slot|
{
if (!slot.isAbstract) return
if (slot.parent === t)
{
if (!errForDef)
{
err("Class '$t.name' must be abstract since it contains abstract slots", t.location)
errForDef = true
}
}
else
{
err("Class '$t.name' must be abstract since it inherits but doesn't override '$slot.qname'", t.location)
}
}
if (compiler.input.isTest)
t.slots.values.sort.each(closure)
else
t.slots.each(closure)
}
private Void checkConstType(TypeDef t)
{
// if not const, nothing to check
if (!t.isConst)
{
// non-const cannot inherit from const class
if (t.base != null && t.base.isConst)
err("Non-const class '$t.name' cannot subclass const class '$t.base'", t.location)
return
}
// const class cannot inherit from non-const class
if (t.base != null && t.base != ns.objType && !t.base.isConst)
err("Const class '$t.name' cannot subclass non-const class '$t.base'", t.location)
// check that each field is const (don't worry about statics
// because they are forced to be const in another check)
t.fieldDefs.each |FieldDef f|
{
if (!f.isConst && !f.isStatic)
err("Const class '$t.name' cannot contain non-const field '$f.name'", f.location)
}
// check that no once methods
t.methodDefs.each |MethodDef m|
{
if (m.isOnce)
err("Const class '$t.name' cannot contain once method '$m.name'", m.location)
}
}
//////////////////////////////////////////////////////////////////////////
// FieldDef
//////////////////////////////////////////////////////////////////////////
override Void visitFieldDef(FieldDef f)
{
// if this field overrides a concrete field,
// then it never gets its own storage
if (f.concreteBase != null)
f.flags &= ~FConst.Storage
// check for invalid flags
checkFieldFlags(f)
// mixins cannot have non-abstract fields
if (curType.isMixin && !f.isAbstract && !f.isStatic)
err("Mixin field '$f.name' must be abstract", f.location)
// abstract field cannot have initialization
if (f.isAbstract && f.init != null)
err("Abstract field '$f.name' cannot have initializer", f.init.location)
// abstract field cannot have getter/setter
if (f.isAbstract && (f.hasGet || f.hasSet))
err("Abstract field '$f.name' cannot have getter or setter", f.location)
}
private Void checkFieldFlags(FieldDef f)
{
flags := f.flags
loc := f.location
// these modifiers are never allowed on a field
if (flags & FConst.Ctor != 0) err("Cannot use 'new' modifier on field", loc)
if (flags & FConst.Final != 0) err("Cannot use 'final' modifier on field", loc)
if (flags & FConst.Native != 0) err("Cannot use 'native' modifier on field", loc)
if (flags & Parser.Once != 0) err("Cannot use 'once' modifier on field", loc)
// check invalid protection combinations
checkProtectionFlags(flags, loc)
// if const
if (flags & FConst.Const != 0)
{
// invalid const flag combo
if (flags & FConst.Abstract != 0) err("Invalid combination of 'const' and 'abstract' modifiers", loc)
else if (flags & FConst.Override != 0) err("Invalid combination of 'const' and 'override' modifiers", loc)
else if (flags & FConst.Virtual != 0) err("Invalid combination of 'const' and 'virtual' modifiers", loc)
// invalid type
if (!isConstFieldType(f.fieldType))
err("Const field '$f.name' has non-const type '$f.fieldType'", loc)
}
else
{
// static fields must be const
if (flags & FConst.Static != 0) err("Static field '$f.name' must be const", loc)
}
// check invalid protection combinations on setter (getter
// can no modifiers which is checked in the parser)
if (f.setter != null)
{
fieldProtection := flags & ~Parser.ProtectionMask
setterProtection := f.set.flags & ~Parser.ProtectionMask
if (fieldProtection != setterProtection)
{
// verify protection flag combinations
checkProtectionFlags(f.set.flags, loc)
// verify that setter has narrowed protection
if (fieldProtection & FConst.Private != 0)
{
if (setterProtection & FConst.Public != 0) err("Setter cannot have wider visibility than the field", loc)
if (setterProtection & FConst.Protected != 0) err("Setter cannot have wider visibility than the field", loc)
if (setterProtection & FConst.Internal != 0) err("Setter cannot have wider visibility than the field", loc)
}
else if (fieldProtection & FConst.Internal != 0)
{
if (setterProtection & FConst.Public != 0) err("Setter cannot have wider visibility than the field", loc)
if (setterProtection & FConst.Protected != 0) err("Setter cannot have wider visibility than the field", loc)
}
else if (fieldProtection & FConst.Protected != 0)
{
if (setterProtection & FConst.Public != 0) err("Setter cannot have wider visibility than the field", loc)
}
}
}
}
private Bool isConstFieldType(CType t)
{
if (t.isConst) return true
t = t.deref
if (t is ListType)
{
list := t as ListType
return isConstFieldType(list.v)
}
if (t is MapType)
{
map := t as MapType
return isConstFieldType(map.k) && isConstFieldType(map.v)
}
if (t.fits(ns.typeType))
{
return true
}
return false
}
//////////////////////////////////////////////////////////////////////////
// MethodDef
//////////////////////////////////////////////////////////////////////////
override Void visitMethodDef(MethodDef m)
{
// check invalid use of flags
checkMethodFlags(m)
// check parameters
checkParams(m)
// check ctors call super (or another this) ctor
if (m.isCtor()) checkCtor(m)
}
private Void checkMethodFlags(MethodDef m)
{
// check field accessors in checkFieldFlags
if (m.isFieldAccessor) return
flags := m.flags
loc := m.location
// these modifiers are never allowed on a method
if (flags & FConst.Final != 0) err("Cannot use 'final' modifier on method", loc)
if (flags & FConst.Const != 0) err("Cannot use 'const' modifier on method", loc)
if (flags & Parser.Readonly != 0) err("Cannot use 'readonly' modifier on method", loc)
// check invalid protection combinations
checkProtectionFlags(flags, loc)
// check invalid constructor flags
if (flags & FConst.Ctor != 0)
{
if (flags & FConst.Abstract != 0) err("Invalid combination of 'new' and 'abstract' modifiers", loc)
else if (flags & FConst.Override != 0) err("Invalid combination of 'new' and 'override' modifiers", loc)
else if (flags & FConst.Virtual != 0) err("Invalid combination of 'new' and 'virtual' modifiers", loc)
if (flags & Parser.Once != 0) err("Invalid combination of 'new' and 'once' modifiers", loc)
if (flags & FConst.Native != 0) err("Invalid combination of 'new' and 'native' modifiers", loc)
if (flags & FConst.Static != 0) err("Invalid combination of 'new' and 'static' modifiers", loc)
}
// check invalid static flags
if (flags & FConst.Static != 0)
{
if (flags & FConst.Abstract != 0) err("Invalid combination of 'static' and 'abstract' modifiers", loc)
else if (flags & FConst.Override != 0) err("Invalid combination of 'static' and 'override' modifiers", loc)
else if (flags & FConst.Virtual != 0) err("Invalid combination of 'static' and 'virtual' modifiers", loc)
if (flags & Parser.Once != 0) err("Invalid combination of 'static' and 'once' modifiers", loc)
}
// check invalid abstract flags
if (flags & FConst.Abstract != 0)
{
if (flags & FConst.Native != 0) err("Invalid combination of 'abstract' and 'native' modifiers", loc)
if (flags & Parser.Once != 0) err("Invalid combination of 'abstract' and 'once' modifiers", loc)
}
// mixins cannot have once methods
if (flags & Parser.Once != 0)
{
if (curType.isMixin)
err("Mixins cannot have once methods", m.location)
}
// normalize method flags after checking
if (m.flags & FConst.Static != 0)
m.flags |= FConst.Const;
}
private Void checkParams(MethodDef m)
{
// check that defs are contiguous after first one
seenDef := false
m.paramDefs.each |ParamDef p|
{
checkParam(p)
if (seenDef)
{
if (p.def == null)
err("Parameter '$p.name' must have default", p.location)
}
else
{
seenDef = p.def != null
}
}
}
private Void checkParam(ParamDef p)
{
// check parameter default type
if (p.def != null && !p.def.fits(p.paramType))
err("'$p.def.ctype' is not assignable to '$p.paramType'", p.def.location)
}
private Void checkCtor(MethodDef m)
{
// mixins cannot have constructors
if (curType.isMixin)
err("Mixins cannot have constructors", m.location)
// ensure super/this constructor is called
if (m.ctorChain == null && !compiler.isSys && !curType.base.isObj && !curType.isSynthetic)
err("Must call super class constructor in '$m.name'", m.location)
}
//////////////////////////////////////////////////////////////////////////
// Statements
//////////////////////////////////////////////////////////////////////////
override Void enterStmt(Stmt stmt)
{
if (stmt.id == StmtId.tryStmt) protectedRegionDepth++
}
override Void exitStmt(Stmt stmt)
{
if (stmt.id == StmtId.tryStmt) protectedRegionDepth--
}
override Void enterFinally(TryStmt stmt)
{
finallyDepth++
}
override Void exitFinally(TryStmt stmt)
{
finallyDepth--
}
override Void visitStmt(Stmt stmt)
{
switch (stmt.id)
{
case StmtId.expr: checkExprStmt((ExprStmt)stmt)
case StmtId.ifStmt: checkIf((IfStmt)stmt)
case StmtId.returnStmt: checkReturn((ReturnStmt)stmt)
case StmtId.throwStmt: checkThrow((ThrowStmt)stmt)
case StmtId.forStmt: checkFor((ForStmt)stmt)
case StmtId.whileStmt: checkWhile((WhileStmt)stmt)
case StmtId.breakStmt: checkBreak((BreakStmt)stmt)
case StmtId.continueStmt: checkContinue((ContinueStmt)stmt)
case StmtId.tryStmt: checkTry((TryStmt)stmt)
case StmtId.switchStmt: checkSwitch((SwitchStmt)stmt)
}
}
private Void checkExprStmt(ExprStmt stmt)
{
if (!stmt.expr.isStmt)
err("Not a statement", stmt.expr.location)
}
private Void checkIf(IfStmt stmt)
{
if (!stmt.condition.ctype.isBool)
{
if (stmt.condition.ctype.isObj)
stmt.condition = cast(stmt.condition, ns.boolType)
else
err("If condition must be Bool, not '$stmt.condition.ctype'", stmt.condition.location)
}
}
private Void checkThrow(ThrowStmt stmt)
{
if (!stmt.exception.fits(ns.errType))
{
if (stmt.exception.ctype.isObj)
stmt.exception = cast(stmt.exception, ns.errType)
else
err("Must throw Err, not '$stmt.exception.ctype'", stmt.exception.location)
}
}
private Void checkFor(ForStmt stmt)
{
if (stmt.condition != null && !stmt.condition.ctype.isBool)
{
if (stmt.condition.ctype.isObj)
stmt.condition = cast(stmt.condition, ns.boolType)
else
err("For condition must be Bool, not '$stmt.condition.ctype'", stmt.condition.location)
}
}
private Void checkWhile(WhileStmt stmt)
{
if (!stmt.condition.ctype.isBool)
{
if (stmt.condition.ctype.isObj)
stmt.condition = cast(stmt.condition, ns.boolType)
else
err("While condition must be Bool, not '$stmt.condition.ctype'", stmt.condition.location)
}
}
private Void checkBreak(BreakStmt stmt)
{
if (stmt.loop == null)
err("Break outside of loop (break is implicit in switch)", stmt.location)
// can't leave control of a finally block
if (finallyDepth > 0)
err("Cannot leave finally block", stmt.location)
}
private Void checkContinue(ContinueStmt stmt)
{
if (stmt.loop == null)
err("Continue outside of loop", stmt.location)
// can't leave control of a finally block
if (finallyDepth > 0)
err("Cannot leave finally block", stmt.location)
}
private Void checkReturn(ReturnStmt stmt)
{
ret := curMethod.ret
if (stmt.expr == null)
{
// this is just a sanity check - it should be caught in parser
if (!ret.isVoid)
err("Must return a value from non-Void method", stmt.location)
}
else
{
if (!stmt.expr.fits(ret))
{
if (stmt.expr.ctype.isObj)
stmt.expr = cast(stmt.expr, ret)
else
err("Cannot return '$stmt.expr.ctype' as '$ret'", stmt.expr.location)
}
}
// can't leave control of a finally block
if (finallyDepth > 0)
err("Cannot leave finally block", stmt.location)
// add temp local var if returning from a protected region,
// we always call this variable "$return" and reuse it if
// already declared by a previous return
if (stmt.expr != null && protectedRegionDepth > 0)
{
v := curMethod.vars.find |MethodVar v->Bool| { return v.name == "\$return" }
if (v == null) v = curMethod.addLocalVar(stmt.expr.ctype, "\$return", null)
stmt.leaveVar = v
}
}
private Void checkTry(TryStmt stmt)
{
caught := CType[,]
stmt.catches.each |Catch c|
{
CType errType := c.errType
if (errType == null) errType = ns.errType
if (!errType.fits(ns.errType))
err("Must catch Err, not '$c.errType'", c.errType.location)
else if (errType.fitsAny(caught))
err("Already caught '$errType'", c.location)
caught.add(errType)
}
}
private Void checkSwitch(SwitchStmt stmt)
{
dups := Int:Int[:]
stmt.cases.each |Case c|
{
for (i:=0; i<c.cases.size; ++i)
{
expr := c.cases[i]
// check comparability of condition and each case
checkCompare(expr, stmt.condition)
// check for dups
literal := expr.asTableSwitchCase
if (literal != null)
{
if (dups[literal] == null)
dups[literal] = literal
else
err("Duplicate case label", expr.location)
}
}
}
}
//////////////////////////////////////////////////////////////////////////
// Expr
//////////////////////////////////////////////////////////////////////////
override Expr visitExpr(Expr expr)
{
switch (expr.id)
{
case ExprId.rangeLiteral: checkRangeLiteral((RangeLiteralExpr)expr)
case ExprId.simpleLiteral: checkSimpleLiteral((SimpleLiteralExpr)expr)
case ExprId.boolNot: checkBool((UnaryExpr)expr)
case ExprId.assign: checkAssign((BinaryExpr)expr)
case ExprId.boolOr:
case ExprId.boolAnd: checkBools((CondExpr)expr)
case ExprId.same:
case ExprId.notSame: checkSame((BinaryExpr)expr)
case ExprId.shortcut: checkShortcut((ShortcutExpr)expr)
case ExprId.call: checkCall((CallExpr)expr)
case ExprId.field: checkField((FieldExpr)expr)
case ExprId.thisExpr: checkThis((ThisExpr)expr)
case ExprId.superExpr: checkSuper((SuperExpr)expr)
case ExprId.isExpr:
case ExprId.asExpr:
case ExprId.cast: checkTypeCheck((TypeCheckExpr)expr)
case ExprId.ternary: checkTernary((TernaryExpr)expr)
case ExprId.withBlock: checkWithBlock((WithBlockExpr)expr)
}
return expr
}
private Void checkRangeLiteral(RangeLiteralExpr range)
{
if (!range.start.ctype.isInt || !range.end.ctype.isInt)
err("Range must be Int..Int, not '${range.start.ctype}..${range.end.ctype}'", range.location)
}
private Void checkSimpleLiteral(SimpleLiteralExpr simple)
{
t := simple.ctype
m := simple.method = t.method("fromStr")
// resolve fromStr method
if (m == null)
{
err("Simple type '$t' missing 'fromStr' method", simple.location)
return
}
// check fromStr is static
if (!m.isStatic)
err("Simple type '${t}.fromStr' not static method", simple.location)
// check fromStr return
if (m.returnType != t)
err("Simple type '${t}.fromStr' returns wrong type", simple.location)
// check fromStr parameters
if (m.params.size < 1)
{
err("Simple type '${t}.fromStr' not enough parameters", simple.location)
}
else
{
if (!m.params[0].paramType.isStr)
err("Simple type '${t}.fromStr' first parameter not Str", simple.location)
if (m.params.size > 1 && !m.params[1].hasDefault)
err("Simple type '${t}.fromStr' too many parameters", simple.location)
}
// check argument is a string
argType := simple.arg.ctype
if (!argType.isStr)
err("Simple literal requires 'Str' argument, not '$argType'", simple.arg.location)
}
private Void checkBool(UnaryExpr expr)
{
operand := expr.operand.ctype
if (!operand.isBool)
{
if (operand.isObj)
expr.operand = cast(expr.operand, ns.boolType)
else
err("Cannot apply '$expr.opToken.symbol' operator to '$operand'", expr.location)
}
}
private Void checkBools(CondExpr expr)
{
expr.operands.each |Expr operand, Int i|
{
if (!operand.ctype.isBool)
{
if (operand.ctype.isObj)
expr.operands[i] = cast(operand, ns.boolType)
else
err("Cannot apply '$expr.opToken.symbol' operator to '$operand.ctype'", operand.location)
}
}
}
private Void checkSame(BinaryExpr expr)
{
checkCompare(expr.lhs, expr.rhs)
}
private Bool checkCompare(Expr lhs, Expr rhs)
{
if (!lhs.fits(rhs.ctype) && !rhs.fits(lhs.ctype))
{
err("Incomparable types '$lhs.ctype' and '$rhs.ctype'", lhs.location)
return false
}
return true
}
private Void checkAssign(BinaryExpr expr)
{
// check that rhs is assignable to lhs
if (!expr.rhs.fits(expr.lhs.ctype))
{
if (expr.rhs.ctype.isObj)
expr.rhs = cast(expr.rhs, expr.lhs.ctype)
else
err("'$expr.rhs.ctype' is not assignable to '$expr.lhs.ctype'", expr.rhs.location)
}
// check that lhs is assignable
if (!expr.lhs.isAssignable)
err("Left hand side is not assignable", expr.lhs.location)
// check left hand side field (common code with checkShortcut)
if (expr.lhs.id === ExprId.field)
checkAssignField((FieldExpr)expr.lhs, expr.rhs)
// take this opportunity to generate a temp local variable if needed
if (expr.leave && expr.lhs.assignRequiresTempVar)
expr.tempVar = curMethod.addLocalVar(expr.ctype, null, null)
}
private Void checkShortcut(ShortcutExpr shortcut)
{
switch (shortcut.opToken)
{
// comparable
case Token.eq: case Token.notEq:
case Token.gt: case Token.gtEq:
case Token.lt: case Token.ltEq:
case Token.cmp:
if (!checkCompare(shortcut.target, shortcut.args.first)) return
}
// if assignment
if (shortcut.isAssign)
{
// check that lhs is assignable
if (!shortcut.target.isAssignable)
err("Target is not assignable", shortcut.target.location)
// check left hand side field (common code with checkAssign)
if (shortcut.target.id === ExprId.field)
checkAssignField((FieldExpr)shortcut.target, shortcut.args.first)
}
// take this oppotunity to generate a temp local variable if needed
if (shortcut.leave && shortcut.isAssign && shortcut.target.assignRequiresTempVar)
shortcut.tempVar = curMethod.addLocalVar(shortcut.ctype, null, null)
// perform normal call checking
checkCall(shortcut)
}
private Void checkAssignField(FieldExpr lhs, Expr rhs)
{
field := ((FieldExpr)lhs).field
// check protection scope (which might be more narrow than the scope
// of the entire field as checked in checkProtection by checkField)
if (field.setter != null && slotProtectionErr(field) == null)
checkSlotProtection(field.setter, lhs.location, true)
// if not-const we are done
if (!field.isConst) return
// check attempt to set static field outside of static initializer
if (field.isStatic && !curMethod.isStaticInit)
{
err("Cannot set const static field '$field.name' outside of static initializer", lhs.location)
return
}
// we allow setting an instance ctor field in a ctor
// based with block, otherwise it need further checking
if (!(lhs.target is WithBaseExpr) || !lhs.target->isCtorWithBlock)
{
// check attempt to set field outside of owning class
if (field.parent != curType)
{
err("Cannot set const field '$field.qname'", lhs.location)
return
}
// check attempt to set instance field outside of ctor
if (!field.isStatic && !(curMethod.isInstanceInit || curMethod.isCtor))
{
err("Cannot set const field '$field.name' outside of constructor", lhs.location)
return
}
}
// if List/Map/Type, verify that rhs assignment is guaranteed immutable;
// any other errors should already be logged at this point (see isConstFieldType)
ftype := field.fieldType
if (ftype.fits(ns.listType) || ftype.fits(ns.mapType) || ftype.fits(ns.typeType))
{
if (!isFieldAssignImmutable(ftype, rhs))
err("Must call ${ftype.name}.toImmutable() when setting const field '$field.name'", rhs.location)
}
}
private Bool isFieldAssignImmutable(CType fieldType, Expr rhs)
{
// skip if field assignment
if (rhs == null) return true
// allow type literal
if (fieldType == ns.typeType && rhs.id == ExprId.typeLiteral)
return true
// otherwise we must have a toImmutable call
return rhs.id == ExprId.call && rhs->method->qname == "sys::${fieldType.name}.toImmutable"
}
private Void checkCall(CallExpr call)
{
m := call.method
if (m == null)
{
err("Something wrong with method call?", call.location)
return
}
name := m.name
// check protection scope
checkSlotProtection(call.method, call.location)
// check arguments
if (!call.isDynamic) checkArgs(call)
// if constructor
if (m.isCtor && !call.isCtorChain)
{
// ensure we aren't calling constructors on an instance
if (call.target != null && call.target.id !== ExprId.staticTarget)
err("Cannot call constructor '$name' on instance", call.location)
// ensure we aren't calling a constructor on an abstract class
if (m.parent.isAbstract)
err("Calling constructor on abstract class", call.location)
}
// ensure we aren't calling static methods on an instance
if (m.isStatic)
{
if (call.target != null && call.target.id !== ExprId.staticTarget)
err("Cannot call static method '$name' on instance", call.location)
}
// ensure we can't calling an instance method statically
if (!m.isStatic && !m.isCtor)
{
if (call.target == null || call.target.id === ExprId.staticTarget)
err("Cannot call instance method '$name' in static context", call.location)
}
// if using super check that concrete
if (call.target != null && call.target.id === ExprId.superExpr)
{
if (m.isAbstract)
err("Cannot use super to call abstract method '$m.qname'", call.target.location)
}
}
private Void checkField(FieldExpr f)
{
field := f.field
// check protection scope
checkSlotProtection(field, f.location)
// ensure we aren't calling static methods on an instance
if (field.isStatic)
{
if (f.target != null && f.target.id !== ExprId.staticTarget)
err("Cannot access static field '$f.name' on instance", f.location)
}
// if instance field
else
{
if (f.target == null || f.target.id === ExprId.staticTarget)
err("Cannot access instance field '$f.name' in static context", f.location)
}
// if using super check that concrete
if (f.target != null && f.target.id === ExprId.superExpr)
{
if (field.isAbstract)
err("Cannot use super to access abstract field '$field.qname'", f.target.location)
}
// if using the field's accessor method
if (f.useAccessor)
{
// check if we can optimize out the accessor (required for constants)
f.useAccessor = useFieldAccessor(field)
// check that we aren't using an field accessor inside of itself
if (curMethod != null && (field.getter === curMethod || field.setter === curMethod))
err("Cannot use field accessor inside accessor itself - use '@' operator", f.location)
}
// if accessing storage directly
else
{
// check that the current class gets access to direct
// field storage (only defining class gets it); allow closures
// same scope priviledges as enclosing class
enclosing := curType.isClosure ? curType.closure.enclosingType : curType
if (!field.isConst && field.parent != curType && field.parent != enclosing)
{
err("Field storage for '$field.qname' not accessible", f.location)
}
// sanity check that field has storage
else if (!field.isStorage)
{
if (field is FieldDef && ((FieldDef)field).concreteBase != null)
err("Field storage of inherited field '${field->concreteBase->qname}' not accessible (might try super)", f.location)
else
err("Invalid storage access of field '$field.qname' which doesn't have storage", f.location)
}
}
}
private Bool useFieldAccessor(CField f)
{
// if there is no getter, then use field directly (constants)
if (f.getter == null) return false
// always use accessor if field is imported from another
// pod (in which case it isn't a def in my compilation unit)
def := f as FieldDef
if (def == null) return true
// if virtual and/or override then always use accessor
if (def.isVirtual || def.isOverride)
return true
// if the field has synthetic getter and setter, then
// we can safely optimize internal field accessors to
// use field directly
if (!def.hasGet && !def.hasSet)
return false
// use accessor since there is a custom getter or setter
return true
}
private Void checkThis(ThisExpr expr)
{
if (inStatic)
err("Cannot access 'this' in static context", expr.location)
}
private Void checkSuper(SuperExpr expr)
{
if (inStatic)
err("Cannot access 'super' in static context", expr.location)
if (curType.isMixin)
{
if (expr.explicitType == null)
err("Must use named 'super' inside mixin", expr.location)
else if (!expr.explicitType.isMixin)
err("Cannot use 'Obj.super' inside mixin (yeah I know - take it up with Sun)", expr.location)
}
if (expr.explicitType != null)
{
if (!curType.fits(expr.explicitType))
err("Named super '$expr.explicitType' not a super class of '$curType.name'", expr.location)
}
}
private Void checkTypeCheck(TypeCheckExpr expr)
{
check := expr.check
target := expr.target.ctype
if (!check.fits(target) && !target.fits(check))
err("Inconvertible types '$target' and '$check'", expr.location)
}
private Void checkTernary(TernaryExpr expr)
{
if (!expr.condition.ctype.isBool)
{
if (expr.condition.ctype.isObj)
expr.condition = cast(expr.condition, ns.boolType)
else
err("Ternary condition must be Bool, not '$expr.condition.ctype'", expr.condition.location)
}
}
private Void checkWithBlock(WithBlockExpr expr)
{
expr.subs.each |Expr sub|
{
if (!sub.isStmt) err("Not a statement", sub.location)
}
}
//////////////////////////////////////////////////////////////////////////
// Check Args
//////////////////////////////////////////////////////////////////////////
private Void checkArgs(CallExpr call)
{
params := call.method.params
name := call.name
args := call.args
isErr := false
// if we are calling callx(A, B...) on a FuncType, then
// use the first class Func signature rather than the
// version of callx which got picked because we might have
// picked the wrong callx version
sig := call.method.parent as FuncType
if (sig != null && name.startsWith("call") && name.size == 5)
{
if (sig.params.size != args.size)
{
isErr = true
}
else
{
sig.params.each |CType p, Int i|
{
arg := args[i]
if (!arg.fits(p))
{
if (arg.ctype.isObj)
args[i] = cast(arg, p)
else
isErr = true
}
}
}
}
// if more args than params, always an err
else if (params.size < args.size)
{
isErr = true
}
// check each arg against each parameter
else
{
params.each |CParam p, Int i|
{
if (i >= args.size)
{
// param has a default value, then that is ok
if (!p.hasDefault) isErr = true
}
else
{
// ensure arg fits parameter type (or auto-cast)
arg := args[i]
if (!arg.fits(p.paramType))
{
if (arg.ctype.isObj)
args[i] = cast(arg, p.paramType)
else
isErr = true
}
}
}
}
if (!isErr) return
msg := "Invalid args "
if (sig != null)
msg += "|" + sig.params.join(", ") + "|"
else
msg += call.method.nameAndParamTypesToStr
msg += ", not (" + args.join(", ", |Expr e->Str| { return "$e.ctype" }) + ")"
err(msg, call.location)
}
//////////////////////////////////////////////////////////////////////////
// Flag Utils
//////////////////////////////////////////////////////////////////////////
private Void checkProtectionFlags(Int flags, Location loc)
{
isPublic := flags & FConst.Public != 0
isProtected := flags & FConst.Protected != 0
isPrivate := flags & FConst.Private != 0
isInternal := flags & FConst.Internal != 0
isVirtual := flags & FConst.Virtual != 0
isOverride := flags & FConst.Override != 0
if (isPublic)
{
if (isProtected) err("Invalid combination of 'public' and 'protected' modifiers", loc)
if (isPrivate) err("Invalid combination of 'public' and 'private' modifiers", loc)
if (isInternal) err("Invalid combination of 'public' and 'internal' modifiers", loc)
}
else if (isProtected)
{
if (isPrivate) err("Invalid combination of 'protected' and 'private' modifiers", loc)
if (isInternal) err("Invalid combination of 'protected' and 'internal' modifiers", loc)
}
else if (isPrivate)
{
if (isInternal) err("Invalid combination of 'private' and 'internal' modifiers", loc)
if (isVirtual && !isOverride) err("Invalid combination of 'private' and 'virtual' modifiers", loc)
}
}
private Void checkSlotProtection(CSlot slot, Location loc, Bool setter := false)
{
errMsg := slotProtectionErr(slot, setter)
if (errMsg != null) err(errMsg, loc)
}
private Str slotProtectionErr(CSlot slot, Bool setter := false)
{
msg := setter ? "setter of field" : (slot is CMethod ? "method" : "field")
// short circuit if method on myself
if (curType == slot.parent)
return null
// allow closures same scope priviledges as enclosing class
myType := curType
if (myType.isClosure)
myType = curType.closure.enclosingType
if (slot.isPrivate && myType != slot.parent)
return "Private $msg '$slot.qname' not accessible"
else if (slot.isProtected && !myType.fits(slot.parent))
return "Protected $msg '$slot.qname' not accessible"
else if (slot.isInternal && myType.pod != slot.parent.pod)
return "Internal $msg '$slot.qname' not accessible"
else
return null
}
//////////////////////////////////////////////////////////////////////////
// Utils
//////////////////////////////////////////////////////////////////////////
private static Expr cast(Expr target, CType to)
{
return TypeCheckExpr.cast(target, to)
}
//////////////////////////////////////////////////////////////////////////
// Fields
//////////////////////////////////////////////////////////////////////////
private Int protectedRegionDepth := 0 // try statement depth
private Int finallyDepth := 0 // finally block depth
}