diff --git a/apps/boko-framework/src/Boko.bux b/apps/boko-framework/src/Boko.bux
index 77371cb..7afe4bd 100644
--- a/apps/boko-framework/src/Boko.bux
+++ b/apps/boko-framework/src/Boko.bux
@@ -242,8 +242,7 @@ func Query_Parse(queryString: String) -> StringMap<String> {
     }
 
     let pairCount: uint = String_SplitCount(queryString, "&");
-    var i: uint = 0;
-    while i < pairCount {
+    for i in 0..pairCount {
         let pair: String = String_SplitPart(queryString, "&", i);
         let eqPos: String = String_Find(pair, "=");
         var key: String = pair;
@@ -258,7 +257,6 @@ func Query_Parse(queryString: String) -> StringMap<String> {
             }
         }
         StringMap_Set<String>(&map, key, value);
-        i = i + 1;
     }
     return map;
 }
@@ -317,8 +315,7 @@ func Request_Parse(raw: String) -> Request {
     }
 
     // Parse headers
-    var i: uint = 1;
-    while i < lineCount {
+    for i in 1..lineCount {
         let line: String = String_SplitPart(headerBlock, "\r\n", i);
         let colonPos: String = String_Find(line, ": ");
         if !String_IsNull(colonPos) {
@@ -332,7 +329,6 @@ func Request_Parse(raw: String) -> Request {
             }
             StringMap_Set<String>(&req.headers, key, value);
         }
-        i = i + 1;
     }
 
     return req;
@@ -349,8 +345,7 @@ func Path_Match(pattern: String, path: String, req: *Request) -> bool {
 
     req.pathParams = StringMap_New<String>(8);
 
-    var i: uint = 0;
-    while i < patParts {
+    for i in 0..patParts {
         let patPart: String = String_SplitPart(pattern, "/", i);
         let pathPart: String = String_SplitPart(path, "/", i);
 
@@ -361,7 +356,6 @@ func Path_Match(pattern: String, path: String, req: *Request) -> bool {
         } else {
             if !String_Eq(patPart, pathPart) { return false; }
         }
-        i = i + 1;
     }
 
     return true;
@@ -462,10 +456,8 @@ func App_Run(app: *App) {
     PrintLine("");
 
     // Spawn workers
-    var i: int = 0;
-    while i < app.threadCount - 1 {
+    for i in 0..(app.threadCount - 1) {
         spawn App_Worker(fd);
-        i = i + 1;
     }
 
     // Main thread is the last worker
diff --git a/bootstrap/hir_lower.nim b/bootstrap/hir_lower.nim
index 73760e4..7f62e41 100644
--- a/bootstrap/hir_lower.nim
+++ b/bootstrap/hir_lower.nim
@@ -481,7 +481,15 @@ proc resolveExprType(ctx: var LowerCtx, expr: Expr): Type =
     return makeSlice(makeUnknown())
   of ekRange:
     let loType = ctx.resolveExprType(expr.exprRangeLo)
-    return makeRange(loType)
+    let hiType = ctx.resolveExprType(expr.exprRangeHi)
+    if loType == hiType:
+      return makeRange(loType)
+    elif loType.isAssignableTo(hiType):
+      return makeRange(hiType)
+    elif hiType.isAssignableTo(loType):
+      return makeRange(loType)
+    else:
+      return makeRange(loType)
   of ekTuple:
     var elems: seq[Type] = @[]
     for e in expr.exprTupleElements:
@@ -1377,7 +1385,8 @@ proc lowerStmt(ctx: var LowerCtx, stmt: Stmt): HirNode =
       let inclusive = iterExpr.exprRangeInclusive
       
       # Determine loop variable type from range bounds
-      let varType = ctx.resolveExprType(iterExpr.exprRangeLo)
+      let rangeType = ctx.resolveExprType(iterExpr)
+      let varType = if rangeType.inner.len > 0: rangeType.inner[0] else: ctx.resolveExprType(iterExpr.exprRangeLo)
       
       # Create: var i = lo; while i < hi { body; i = i + 1; }
       let initStmt = hirAlloca(varName, varType, loc)
diff --git a/bootstrap/sema.nim b/bootstrap/sema.nim
index b4a04ee..1473c73 100644
--- a/bootstrap/sema.nim
+++ b/bootstrap/sema.nim
@@ -1007,9 +1007,16 @@ proc checkExpr(sema: var Sema, expr: Expr, scope: Scope): Type =
   of ekRange:
     let lo = sema.checkExpr(expr.exprRangeLo, scope)
     let hi = sema.checkExpr(expr.exprRangeHi, scope)
-    if lo != hi:
+    var rangeType: Type = lo
+    if lo == hi:
+      rangeType = lo
+    elif lo.isAssignableTo(hi):
+      rangeType = hi
+    elif hi.isAssignableTo(lo):
+      rangeType = lo
+    else:
       sema.emitError(expr.loc, "range bounds must have same type")
-    return makeRange(lo)
+    return makeRange(rangeType)
   of ekCall:
     if expr.exprCallCallee == nil:
       sema.emitError(expr.loc, "internal error: nil callee in call expression")