bugfix: case exhaustiveness checking

compiler/astalgo.nim

@@ -156,6 +156,10 @@ proc skipConv*(n: PNode): PNode =
     result = n.sons[1]
   else: result = n
 
+proc skipConvTakeType*(n: PNode): PNode =
+  result = n.skipConv
+  result.typ = n.typ
+
 proc SameValue*(a, b: PNode): bool = 
   result = false
   case a.kind

compiler/nimsets.nim

@@ -44,9 +44,9 @@ proc inSet(s: PNode, elem: PNode): bool =
         return true
   result = false
 
-proc overlap(a, b: PNode): bool = 
-  if a.kind == nkRange: 
-    if b.kind == nkRange: 
+proc overlap(a, b: PNode): bool =
+  if a.kind == nkRange:
+    if b.kind == nkRange:
       # X..Y and C..D overlap iff (X <= D and C <= Y)
       result = leValue(a.sons[0], b.sons[1]) and
                leValue(b.sons[0], a.sons[1])

compiler/semtypes.nim

@@ -323,8 +323,8 @@ proc semBranchRange(c: PContext, t, a, b: PNode, covered: var biggestInt): PNode
   checkMinSonsLen(t, 1)
   let ac = semConstExpr(c, a)
   let bc = semConstExpr(c, b)
-  let at = fitNode(c, t.sons[0].typ, ac)
-  let bt = fitNode(c, t.sons[0].typ, bc)
+  let at = fitNode(c, t.sons[0].typ, ac).skipConvTakeType
+  let bt = fitNode(c, t.sons[0].typ, bc).skipConvTakeType
   
   result = newNodeI(nkRange, a.info)
   result.add(at)

tests/reject/tcaseoverlaprange2.nim

@@ -0,0 +1,18 @@
+discard """
+  line: 13
+  errormsg: "duplicate case label"
+"""
+
+
+
+
+proc checkDuplicates(myval: int32): bool = 
+  case myval
+  of 0x7B:
+    echo "this should not compile"
+  of 0x78 .. 0x7D:
+    result = true
+  else:
+    nil
+
+echo checkDuplicates(0x7B)

todo.txt

@@ -31,7 +31,6 @@ Bugs
 - osproc execProcesses can deadlock if all processes fail (as experienced
   in c++ mode)
 - bootstrapping does not work in C++ mode
-- case statement exhaustiveness checking is still wrong
 - the new m&s GC is still buggy