fix #19678 Broken behavior with string ranges in case labels (#20475)

* fix #19678 Broken behavior with string ranges in case labels * Update compiler/semtypes.nim Co-authored-by: Andreas Rumpf <rumpf_a@web.de> Co-authored-by: Andreas Rumpf <rumpf_a@web.de>
nim-lang · Oct 1, 2022 · cbd9fee · cbd9fee
1 parent 8d47bf1
commit cbd9fee
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diff --git a/compiler/semtypes.nim b/compiler/semtypes.nim
@@ -554,6 +554,8 @@ proc semBranchRange(c: PContext, t, a, b: PNode, covered: var Int128): PNode =
   checkMinSonsLen(t, 1, c.config)
   let ac = semConstExpr(c, a)
   let bc = semConstExpr(c, b)
+  if ac.kind in {nkStrLit..nkTripleStrLit} or bc.kind in {nkStrLit..nkTripleStrLit}:
+    localError(c.config, b.info, "range of string is invalid")
   let at = fitNode(c, t[0].typ, ac, ac.info).skipConvTakeType
   let bt = fitNode(c, t[0].typ, bc, bc.info).skipConvTakeType
 

diff --git a/tests/range/t19678.nim b/tests/range/t19678.nim
@@ -0,0 +1,17 @@
+discard """
+  cmd: "nim check --hints:off $file"
+  errormsg: ""
+  nimout: '''
+t19678.nim(13, 13) Error: range of string is invalid
+
+
+
+'''
+"""
+
+case "5":
+  of "0" .. "9":
+    discard
+  else:
+    discard
+