fixes #794

compiler/seminst.nim

@@ -11,12 +11,12 @@
 # included from sem.nim
 
 proc instantiateGenericParamList(c: PContext, n: PNode, pt: TIdTable,
-                                 entry: var TInstantiation) = 
-  if n.kind != nkGenericParams: 
+                                 entry: var TInstantiation) =
+  if n.kind != nkGenericParams:
     internalError(n.info, "instantiateGenericParamList; no generic params")
   newSeq(entry.concreteTypes, n.len)
   for i, a in n.pairs:
-    if a.kind != nkSym: 
+    if a.kind != nkSym:
       internalError(a.info, "instantiateGenericParamList; no symbol")
     var q = a.sym
     if q.typ.kind notin {tyTypeDesc, tyGenericParam, tyStatic, tyIter}+tyTypeClasses:
@@ -27,13 +27,13 @@ proc instantiateGenericParamList(c: PContext, n: PNode, pt: TIdTable,
     var t = PType(idTableGet(pt, q.typ))
     if t == nil:
       if tfRetType in q.typ.flags:
-        # keep the generic type and allow the return type to be bound 
+        # keep the generic type and allow the return type to be bound
         # later by semAsgn in return type inference scenario
         t = q.typ
       else:
         localError(a.info, errCannotInstantiateX, s.name.s)
         t = errorType(c)
-    elif t.kind == tyGenericParam: 
+    elif t.kind == tyGenericParam:
       localError(a.info, errCannotInstantiateX, q.name.s)
       t = errorType(c)
     elif t.kind == tyGenericInvocation:
@@ -58,17 +58,17 @@ proc genericCacheGet(genericSym: PSym, entry: TInstantiation): PSym =
       if sameInstantiation(entry, inst[]):
         return inst.sym
 
-proc removeDefaultParamValues(n: PNode) = 
+proc removeDefaultParamValues(n: PNode) =
   # we remove default params, because they cannot be instantiated properly
   # and they are not needed anyway for instantiation (each param is already
   # provided).
   when false:
-    for i in countup(1, sonsLen(n)-1): 
+    for i in countup(1, sonsLen(n)-1):
       var a = n.sons[i]
       if a.kind != nkIdentDefs: IllFormedAst(a)
       var L = a.len
       if a.sons[L-1].kind != nkEmpty and a.sons[L-2].kind != nkEmpty:
-        # ``param: typ = defaultVal``. 
+        # ``param: typ = defaultVal``.
         # We don't need defaultVal for semantic checking and it's wrong for
         # ``cmp: proc (a, b: T): int = cmp``. Hm, for ``cmp = cmp`` that is
         # not possible... XXX We don't solve this issue here.
@@ -97,7 +97,7 @@ proc addProcDecls(c: PContext, fn: PSym) =
     var param = fn.typ.n.sons[i].sym
     param.owner = fn
     addParamOrResult(c, param, fn.kind)
-  
+
   maybeAddResult(c, fn, fn.ast)
 
 proc instantiateBody(c: PContext, n, params: PNode, result: PSym) =
@@ -132,9 +132,9 @@ proc fixupInstantiatedSymbols(c: PContext, s: PSym) =
       closeScope(c)
       popInfoContext()
 
-proc sideEffectsCheck(c: PContext, s: PSym) = 
+proc sideEffectsCheck(c: PContext, s: PSym) =
   if {sfNoSideEffect, sfSideEffect} * s.flags ==
-      {sfNoSideEffect, sfSideEffect}: 
+      {sfNoSideEffect, sfSideEffect}:
     localError(s.info, errXhasSideEffects, s.name.s)
 
 proc instGenericContainer(c: PContext, info: TLineInfo, header: PType,
@@ -162,18 +162,18 @@ proc instantiateProcType(c: PContext, pt: TIdTable,
   # Alas, doing this here is probably not enough, because another
   # proc signature could appear in the params:
   # proc foo[T](a: proc (x: T, b: type(x.y))
-  #   
+  #
   # The solution would be to move this logic into semtypinst, but
   # at this point semtypinst have to become part of sem, because it
   # will need to use openScope, addDecl, etc.
   addDecl(c, prc)
-  
+
   pushInfoContext(info)
   var cl = initTypeVars(c, pt, info)
   var result = instCopyType(cl, prc.typ)
   let originalParams = result.n
   result.n = originalParams.shallowCopy
-  
+
   for i in 1 .. <result.len:
     # twrong_field_caching requires these 'resetIdTable' calls:
     if i > 1: resetIdTable(cl.symMap)
@@ -198,10 +198,10 @@ proc instantiateProcType(c: PContext, pt: TIdTable,
   resetIdTable(cl.symMap)
   result.sons[0] = replaceTypeVarsT(cl, result.sons[0])
   result.n.sons[0] = originalParams[0].copyTree
-  
+
   eraseVoidParams(result)
   skipIntLiteralParams(result)
- 
+
   prc.typ = result
   maybeAddResult(c, prc, prc.ast)
   popInfoContext()

compiler/types.nim

@@ -823,8 +823,13 @@ proc sameEnumTypes*(a, b: PType): bool {.inline.} =
 proc sameObjectTree(a, b: PNode, c: var TSameTypeClosure): bool =
   if a == b:
     result = true
-  elif (a != nil) and (b != nil) and (a.kind == b.kind):
-    if sameTypeOrNilAux(a.typ, b.typ, c):
+  elif a != nil and b != nil and a.kind == b.kind:
+    var x = a.typ
+    var y = b.typ
+    if IgnoreTupleFields in c.flags:
+      if x != nil: x = skipTypes(x, {tyRange, tyGenericInst})
+      if y != nil: y = skipTypes(y, {tyRange, tyGenericInst})
+    if sameTypeOrNilAux(x, y, c):
       case a.kind
       of nkSym:
         # same symbol as string is enough:

tests/ccgbugs/tstringslice.nim

@@ -0,0 +1,10 @@
+
+# bug #794
+type TRange = range[0..3]
+
+const str = "123456789"
+
+for i in TRange.low .. TRange.high:
+  echo str[i]                          #This works fine
+  echo str[int(i) .. int(TRange.high)] #So does this
+  echo str[i .. TRange.high]           #The compiler complains about this