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Fix #1961: Allow * as an infix operator #3907

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Merged
merged 1 commit into from
Jan 25, 2018
Merged

Fix #1961: Allow * as an infix operator #3907

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16 changes: 12 additions & 4 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 @@ -470,11 +470,11 @@ object Parsers {
def infixOps(
first: Tree, canStartOperand: Token => Boolean, operand: () => Tree,
isType: Boolean = false,
notAnOperator: Name = nme.EMPTY,
isOperator: => Boolean = true,
maybePostfix: Boolean = false): Tree = {
val base = opStack
var top = first
while (isIdent && in.name != notAnOperator) {
while (isIdent && isOperator) {
val op = if (isType) typeIdent() else termIdent()
top = reduceStack(base, top, precedence(op.name), isLeftAssoc(op.name), op.name)
opStack = OpInfo(top, op, in.offset) :: opStack
Expand Down Expand Up @@ -797,8 +797,16 @@ object Parsers {
*/
def infixType(): Tree = infixTypeRest(refinedType())

/** Is current ident a `*`, and is it followed by a `)` or `,`? */
def isPostfixStar: Boolean =
in.name == nme.raw.STAR && {
val lookahead = in.lookaheadScanner
lookahead.nextToken()
(lookahead.token == RPAREN || lookahead.token == COMMA)
}

def infixTypeRest(t: Tree): Tree =
infixOps(t, canStartTypeTokens, refinedType, isType = true, notAnOperator = nme.raw.STAR)
infixOps(t, canStartTypeTokens, refinedType, isType = true, isOperator = !isPostfixStar)

/** RefinedType ::= WithType {Annotation | [nl] Refinement}
*/
Expand Down Expand Up @@ -1556,7 +1564,7 @@ object Parsers {
/** InfixPattern ::= SimplePattern {id [nl] SimplePattern}
*/
def infixPattern(): Tree =
infixOps(simplePattern(), canStartExpressionTokens, simplePattern, notAnOperator = nme.raw.BAR)
infixOps(simplePattern(), canStartExpressionTokens, simplePattern, isOperator = in.name != nme.raw.BAR)

/** SimplePattern ::= PatVar
* | Literal
Expand Down
4 changes: 4 additions & 0 deletions tests/pos/i1961.scala
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Original file line number Diff line number Diff line change
@@ -0,0 +1,4 @@
object InfixType {
trait *[N1, N2]
type Result = Int * Int
}