diff --git a/loki/transform/transform_scalar_syntax.py b/loki/transform/transform_scalar_syntax.py
index db2b2c62c..60876df58 100644
--- a/loki/transform/transform_scalar_syntax.py
+++ b/loki/transform/transform_scalar_syntax.py
@@ -7,12 +7,13 @@
 
 from loki.expression import (
     Sum, Product, IntLiteral, Scalar, Array, RangeIndex,
-    TypedSymbol, SubstituteExpressions
+    SubstituteExpressions
     )
 from loki.ir import CallStatement
 from loki.visitors import FindNodes, Transformer
 from loki.tools import as_tuple
 from loki.types import BasicType
+import pymbolic.primitives as pmbl
 
 
 __all__ = [
@@ -37,6 +38,39 @@ def check_if_scalar_syntax(arg, dummy):
     return False
 
 
+def single_sum(expr):
+    if isinstance(expr, pmbl.Sum):
+        return expr
+    else:
+        return Sum((expr,))
+
+
+def sum_ints(expr):
+    if isinstance(expr, pmbl.Sum):
+        n = 0
+        new_children = []
+        for c in expr.children:
+            if isinstance(c, IntLiteral):
+                n += c.value
+            elif (isinstance(c, pmbl.Product) and
+                  all(isinstance(cc, IntLiteral) or isinstance(cc,int) for cc in c.children)):
+                m = 1
+                for cc in c.children:
+                    if isinstance(cc, IntLiteral):
+                        m = m*cc.value
+                    else:
+                        m = m*cc
+                n += m
+            else:
+                new_children += [c]
+
+        if n != 0:
+            new_children += [IntLiteral(n)]
+
+        expr.children = as_tuple(new_children)
+                  
+
+
 def construct_range_index(lower, length):
 
     if lower == IntLiteral(1):
@@ -44,11 +78,13 @@ def construct_range_index(lower, length):
     elif isinstance(lower, IntLiteral) and isinstance(length, IntLiteral):
         new_high = IntLiteral(value = length.value + lower.value - 1)
     elif isinstance(lower, IntLiteral):
-        new_high = Sum((length,IntLiteral(value = lower.value - 1)))
+        new_high = single_sum(length) + IntLiteral(value = lower.value - 1)
     elif isinstance(length, IntLiteral):
-        new_high = Sum((lower,IntLiteral(value = length.value - 1)))
+        new_high = single_sum(lower) + IntLiteral(value = length.value - 1)
     else:
-        new_high = Sum((lower, length, Product((-1, IntLiteral(1)))))
+        new_high = single_sum(length) + lower - IntLiteral(1)
+
+    sum_ints(new_high)
 
     return RangeIndex((lower, new_high))
 
@@ -58,13 +94,12 @@ def process_symbol(symbol, caller, call):
     if isinstance(symbol, IntLiteral):
         return symbol
 
-    elif isinstance(symbol, Scalar):
+    elif not symbol.parents:
         if symbol in call.routine.arguments:
             return call.arg_map[symbol]
 
-    elif isinstance(symbol, TypedSymbol):
-        if symbol.parents[0] in call.routine.arguments:
-            return SubstituteExpressions(call.arg_map).visit(symbol)
+    elif symbol.parents[0] in call.routine.arguments:
+        return SubstituteExpressions(call.arg_map).visit(symbol.clone(scope=caller))
 
     if call.routine in caller.members and symbol in caller.variables:
         return symbol
@@ -80,11 +115,11 @@ def construct_length(xrange, routine, call):
     if isinstance(new_start, IntLiteral) and isinstance(new_stop, IntLiteral):
         return IntLiteral(value = new_stop.value - new_start.value + 1)
     elif isinstance(new_start, IntLiteral):
-        return Sum((new_stop, Product((-1,(IntLiteral(value = new_start.value - 1))))))
+        return single_sum(new_stop) - IntLiteral(value = new_start.value - 1)
     elif isinstance(new_stop, IntLiteral):
-        return Sum((IntLiteral(value = new_stop.value + 1), Product((-1,new_start))))
+        return single_sum(IntLiteral(value = new_stop.value + 1)) - new_start
     else:
-        return Sum((new_stop, Product((-1,new_start)), IntLiteral(1)))
+        return single_sum(new_stop) - new_start + IntLiteral(1)
 
 
 def fix_scalar_syntax(routine):