Fix #5640 Typer crash on 0 arity tuple

eklavya · eklavya · commit 871a87eaa8c9 · 2018-12-25T20:57:04.000+05:30
diff --git a/compiler/src/dotty/tools/dotc/ast/Desugar.scala b/compiler/src/dotty/tools/dotc/ast/Desugar.scala
@@ -920,8 +920,8 @@ object desugar {
     assert(arity <= Definitions.MaxTupleArity)
     def tupleTypeRef = defn.TupleType(arity)
     if (arity == 1) ts.head
-    else if (ctx.mode is Mode.Type) AppliedTypeTree(ref(tupleTypeRef), ts)
     else if (arity == 0) unitLiteral
+    else if (ctx.mode is Mode.Type) AppliedTypeTree(ref(tupleTypeRef), ts)
     else Apply(ref(tupleTypeRef.classSymbol.companionModule.termRef), ts)
   }
 
diff --git a/tests/neg/i5640.scala b/tests/neg/i5640.scala
@@ -0,0 +1,3 @@
+object test {
+  val foo = (()) => () // error: not a legal formal parameter
+}

Original file line number	Diff line number	Diff line change
`@@ -920,8 +920,8 @@ object desugar {`
`920`	`920`	`assert(arity <= Definitions.MaxTupleArity)`
`921`	`921`	`def tupleTypeRef = defn.TupleType(arity)`
`922`	`922`	`if (arity == 1) ts.head`
`923`		`- else if (ctx.mode is Mode.Type) AppliedTypeTree(ref(tupleTypeRef), ts)`
`924`	`923`	`else if (arity == 0) unitLiteral`
	`924`	`+ else if (ctx.mode is Mode.Type) AppliedTypeTree(ref(tupleTypeRef), ts)`
`925`	`925`	`else Apply(ref(tupleTypeRef.classSymbol.companionModule.termRef), ts)`
`926`	`926`	`}`
`927`	`927`
Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,3 @@`
	`1`	`+object test {`
	`2`	`+ val foo = (()) => () // error: not a legal formal parameter`
	`3`	`+}`