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Fix #1707: Survive non-existing positions in parser #1719

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Merged
merged 3 commits into from
Nov 24, 2016
Merged

Fix #1707: Survive non-existing positions in parser #1719

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40c1913
More robust scheme for taking start/end of positions when parsing
odersky Nov 17, 2016
18eea6b
Rename ...Pos to ...Offset and add pointOffset
odersky Nov 17, 2016
3d20226
Renamed test file to give correct issue number
odersky Nov 24, 2016
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76 changes: 43 additions & 33 deletions compiler/src/dotty/tools/dotc/parsing/Parsers.scala
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Original file line number Diff line number Diff line change
Expand Up @@ -83,6 +83,15 @@ object Parsers {
def atPos[T <: Positioned](start: Offset)(t: T): T =
atPos(start, start)(t)

def startOffset(t: Positioned): Int =
if (t.pos.exists) t.pos.start else in.offset

def pointOffset(t: Positioned): Int =
if (t.pos.exists) t.pos.point else in.offset

def endOffset(t: Positioned): Int =
if (t.pos.exists) t.pos.end else in.lastOffset

def nameStart: Offset =
if (in.token == BACKQUOTED_IDENT) in.offset + 1 else in.offset

Expand Down Expand Up @@ -448,7 +457,7 @@ object Parsers {
val topInfo = opStack.head
opStack = opStack.tail
val od = reduceStack(base, topInfo.operand, 0, true)
return atPos(od.pos.start, topInfo.offset) {
return atPos(startOffset(od), topInfo.offset) {
PostfixOp(od, topInfo.operator)
}
}
Expand Down Expand Up @@ -492,7 +501,7 @@ object Parsers {

/** Accept identifier acting as a selector on given tree `t`. */
def selector(t: Tree): Tree =
atPos(t.pos.start, in.offset) { Select(t, ident()) }
atPos(startOffset(t), in.offset) { Select(t, ident()) }

/** Selectors ::= ident { `.' ident()
*
Expand Down Expand Up @@ -728,7 +737,7 @@ object Parsers {

def refinedTypeRest(t: Tree): Tree = {
newLineOptWhenFollowedBy(LBRACE)
if (in.token == LBRACE) refinedTypeRest(atPos(t.pos.start) { RefinedTypeTree(t, refinement()) })
if (in.token == LBRACE) refinedTypeRest(atPos(startOffset(t)) { RefinedTypeTree(t, refinement()) })
else t
}

Expand All @@ -749,7 +758,7 @@ object Parsers {
def annotType(): Tree = annotTypeRest(simpleType())

def annotTypeRest(t: Tree): Tree =
if (in.token == AT) annotTypeRest(atPos(t.pos.start) { Annotated(t, annot()) })
if (in.token == AT) annotTypeRest(atPos(startOffset(t)) { Annotated(t, annot()) })
else t

/** SimpleType ::= SimpleType TypeArgs
Expand Down Expand Up @@ -780,19 +789,19 @@ object Parsers {
val handleSingletonType: Tree => Tree = t =>
if (in.token == TYPE) {
in.nextToken()
atPos(t.pos.start) { SingletonTypeTree(t) }
atPos(startOffset(t)) { SingletonTypeTree(t) }
} else t

private def simpleTypeRest(t: Tree): Tree = in.token match {
case HASH => simpleTypeRest(typeProjection(t))
case LBRACKET => simpleTypeRest(atPos(t.pos.start) { AppliedTypeTree(t, typeArgs(namedOK = true)) })
case LBRACKET => simpleTypeRest(atPos(startOffset(t)) { AppliedTypeTree(t, typeArgs(namedOK = true)) })
case _ => t
}

private def typeProjection(t: Tree): Tree = {
accept(HASH)
val id = typeIdent()
atPos(t.pos.start, id.pos.start) { Select(t, id.name) }
atPos(startOffset(t), startOffset(id)) { Select(t, id.name) }
}

/** NamedTypeArg ::= id `=' Type
Expand Down Expand Up @@ -846,7 +855,7 @@ object Parsers {
val t = toplevelTyp()
if (isIdent(nme.raw.STAR)) {
in.nextToken()
atPos(t.pos.start) { PostfixOp(t, nme.raw.STAR) }
atPos(startOffset(t)) { PostfixOp(t, nme.raw.STAR) }
} else t
}

Expand Down Expand Up @@ -971,7 +980,7 @@ object Parsers {
val t = expr1(location)
if (in.token == ARROW) {
placeholderParams = saved
closureRest(t.pos.start, location, convertToParams(t))
closureRest(startOffset(t), location, convertToParams(t))
}
else if (isWildcard(t)) {
placeholderParams = placeholderParams ::: saved
Expand Down Expand Up @@ -1025,7 +1034,7 @@ object Parsers {
assert(handlerStart != -1)
syntaxError(
new EmptyCatchBlock(body),
Position(handlerStart, handler.pos.end)
Position(handlerStart, endOffset(handler))
)
case _ =>
}
Expand All @@ -1035,7 +1044,7 @@ object Parsers {
else {
if (handler.isEmpty) warning(
EmptyCatchAndFinallyBlock(body),
source atPos Position(tryOffset, body.pos.end)
source atPos Position(tryOffset, endOffset(body))
)
EmptyTree
}
Expand All @@ -1057,21 +1066,21 @@ object Parsers {
case EQUALS =>
t match {
case Ident(_) | Select(_, _) | Apply(_, _) =>
atPos(t.pos.start, in.skipToken()) { Assign(t, expr()) }
atPos(startOffset(t), in.skipToken()) { Assign(t, expr()) }
case _ =>
t
}
case COLON =>
ascription(t, location)
case MATCH =>
atPos(t.pos.start, in.skipToken()) {
atPos(startOffset(t), in.skipToken()) {
inBraces(Match(t, caseClauses()))
}
case _ =>
t
}

def ascription(t: Tree, location: Location.Value) = atPos(t.pos.start, in.skipToken()) {
def ascription(t: Tree, location: Location.Value) = atPos(startOffset(t), in.skipToken()) {
in.token match {
case USCORE =>
val uscoreStart = in.skipToken()
Expand Down Expand Up @@ -1105,7 +1114,7 @@ object Parsers {
val id = termIdent()
val paramExpr =
if (location == Location.InBlock && in.token == COLON)
atPos(id.pos.start, in.skipToken()) { Typed(id, infixType()) }
atPos(startOffset(id), in.skipToken()) { Typed(id, infixType()) }
else
id
closureRest(start, location, convertToParam(paramExpr, mods) :: Nil)
Expand Down Expand Up @@ -1194,13 +1203,13 @@ object Parsers {
in.nextToken()
simpleExprRest(selector(t), canApply = true)
case LBRACKET =>
val tapp = atPos(t.pos.start, in.offset) { TypeApply(t, typeArgs(namedOK = true)) }
val tapp = atPos(startOffset(t), in.offset) { TypeApply(t, typeArgs(namedOK = true)) }
simpleExprRest(tapp, canApply = true)
case LPAREN | LBRACE if canApply =>
val app = atPos(t.pos.start, in.offset) { Apply(t, argumentExprs()) }
val app = atPos(startOffset(t), in.offset) { Apply(t, argumentExprs()) }
simpleExprRest(app, canApply = true)
case USCORE =>
atPos(t.pos.start, in.skipToken()) { PostfixOp(t, nme.WILDCARD) }
atPos(startOffset(t), in.skipToken()) { PostfixOp(t, nme.WILDCARD) }
case _ =>
t
}
Expand Down Expand Up @@ -1284,7 +1293,7 @@ object Parsers {
if (in.token == IF) guard()
else {
val pat = pattern1()
if (in.token == EQUALS) atPos(pat.pos.start, in.skipToken()) { GenAlias(pat, expr()) }
if (in.token == EQUALS) atPos(startOffset(pat), in.skipToken()) { GenAlias(pat, expr()) }
else generatorRest(pat)
}

Expand All @@ -1293,7 +1302,7 @@ object Parsers {
def generator(): Tree = generatorRest(pattern1())

def generatorRest(pat: Tree) =
atPos(pat.pos.start, accept(LARROW)) { GenFrom(pat, expr()) }
atPos(startOffset(pat), accept(LARROW)) { GenFrom(pat, expr()) }

/** ForExpr ::= `for' (`(' Enumerators `)' | `{' Enumerators `}')
* {nl} [`yield'] Expr
Expand Down Expand Up @@ -1357,7 +1366,7 @@ object Parsers {
val pattern = () => {
val pat = pattern1()
if (isIdent(nme.raw.BAR))
atPos(pat.pos.start) { Alternative(pat :: patternAlts()) }
atPos(startOffset(pat)) { Alternative(pat :: patternAlts()) }
else pat
}

Expand All @@ -1383,15 +1392,15 @@ object Parsers {
// compatibility for Scala2 `x @ _*` syntax
infixPattern() match {
case pt @ Ident(tpnme.WILDCARD_STAR) =>
migrationWarningOrError("The syntax `x @ _*' is no longer supported; use `x : _*' instead", p.pos.start)
atPos(p.pos.start, offset) { Typed(p, pt) }
migrationWarningOrError("The syntax `x @ _*' is no longer supported; use `x : _*' instead", startOffset(p))
atPos(startOffset(p), offset) { Typed(p, pt) }
case p =>
atPos(p.pos.start, offset) { Bind(name, p) }
atPos(startOffset(p), offset) { Bind(name, p) }
}
case p @ Ident(tpnme.WILDCARD_STAR) =>
// compatibility for Scala2 `_*` syntax
migrationWarningOrError("The syntax `_*' is no longer supported; use `x : _*' instead", p.pos.start)
atPos(p.pos.start) { Typed(Ident(nme.WILDCARD), p) }
migrationWarningOrError("The syntax `_*' is no longer supported; use `x : _*' instead", startOffset(p))
atPos(startOffset(p)) { Typed(Ident(nme.WILDCARD), p) }
case p =>
p
}
Expand All @@ -1415,7 +1424,7 @@ object Parsers {
val simplePattern = () => in.token match {
case IDENTIFIER | BACKQUOTED_IDENT | THIS =>
path(thisOK = true) match {
case id @ Ident(nme.raw.MINUS) if isNumericLit => literal(id.pos.start)
case id @ Ident(nme.raw.MINUS) if isNumericLit => literal(startOffset(id))
case t => simplePatternRest(t)
}
case USCORE =>
Expand Down Expand Up @@ -1445,9 +1454,9 @@ object Parsers {
def simplePatternRest(t: Tree): Tree = {
var p = t
if (in.token == LBRACKET)
p = atPos(t.pos.start, in.offset) { TypeApply(p, typeArgs()) }
p = atPos(startOffset(t), in.offset) { TypeApply(p, typeArgs()) }
if (in.token == LPAREN)
p = atPos(t.pos.start, in.offset) { Apply(p, argumentPatterns()) }
p = atPos(startOffset(t), in.offset) { Apply(p, argumentPatterns()) }
p
}

Expand Down Expand Up @@ -1573,7 +1582,8 @@ object Parsers {
case Select(qual, name) => cpy.Select(tree)(adjustStart(start)(qual), name)
case _ => tree
}
if (start < tree1.pos.start) tree1.withPos(tree1.pos.withStart(start))
if (tree1.pos.exists && start < tree1.pos.start)
tree1.withPos(tree1.pos.withStart(start))
else tree1
}

Expand Down Expand Up @@ -1771,7 +1781,7 @@ object Parsers {
case imp: Import =>
imp
case sel @ Select(qual, name) =>
val selector = atPos(sel.pos.point) { Ident(name) }
val selector = atPos(pointOffset(sel)) { Ident(name) }
cpy.Import(sel)(qual, selector :: Nil)
case t =>
accept(DOT)
Expand Down Expand Up @@ -1804,7 +1814,7 @@ object Parsers {
def importSelector(): Tree = {
val from = termIdentOrWildcard()
if (from.name != nme.WILDCARD && in.token == ARROW)
atPos(from.pos.start, in.skipToken()) {
atPos(startOffset(from), in.skipToken()) {
Thicket(from, termIdentOrWildcard())
}
else from
Expand Down Expand Up @@ -2085,7 +2095,7 @@ object Parsers {

/** Create a tree representing a packaging */
def makePackaging(start: Int, pkg: Tree, stats: List[Tree]): PackageDef = pkg match {
case x: RefTree => atPos(start, pkg.pos.point)(PackageDef(x, stats))
case x: RefTree => atPos(start, pointOffset(pkg))(PackageDef(x, stats))
}

/** Packaging ::= package QualId [nl] `{' TopStatSeq `}'
Expand Down
24 changes: 24 additions & 0 deletions tests/neg/i1707.scala
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Original file line number Diff line number Diff line change
@@ -0,0 +1,24 @@
object DepBug {
class A {
class B
def mkB = new B
def m(b: B) = b
}
trait Dep {
val a: A
val b: a.B
}
val dep = new {
val a = new A
val b = a mkB
}
def useDep(d: Dep) { // error: procedure syntax
import d._
a m (b)
}
{ // error: Null does not take parameters (follow on)
import dep._
a m (b)
}
dep.a m (dep b) // error (follow on)
}