diff --git a/il65/compile.py b/il65/compile.py
index 2caac21d8..0b86b820b 100644
--- a/il65/compile.py
+++ b/il65/compile.py
@@ -137,6 +137,12 @@ class PlyParser:
             if isinstance(node, Block):
                 if node in encountered_blocks:
                     raise CompileError("parse tree malformed; block duplicated", node, node.name, node.sourceref)
+                if node.name is None:
+                    # blocks without names are possible, in this case their address is specified
+                    if node.address is not None:
+                        continue
+                    else:
+                        raise ParseError("block without name must have address", node.sourceref)
                 parentname = (node.parent.name + ".") if node.parent else ""
                 blockname = parentname + node.name
                 if blockname in encountered_block_names:
diff --git a/il65/emit/__init__.py b/il65/emit/__init__.py
index 12124fa0e..0de064138 100644
--- a/il65/emit/__init__.py
+++ b/il65/emit/__init__.py
@@ -127,3 +127,8 @@ def preserving_registers(registers: Set[str], scope: Scope, out: Callable, loads
             out("\t\tpla")
     else:
         yield
+
+
+def scoped_name(node_with_name: AstNode, current_scope: Scope) -> str:
+    node_scope = node_with_name.my_scope()
+    return node_with_name.name if node_scope is current_scope else node_scope.name + "." + node_with_name.name
diff --git a/il65/emit/incrdecr.py b/il65/emit/incrdecr.py
index 489a9f7b7..8eb6b057b 100644
--- a/il65/emit/incrdecr.py
+++ b/il65/emit/incrdecr.py
@@ -9,7 +9,7 @@ Written by Irmen de Jong (irmen@razorvine.net) - license: GNU GPL 3.0
 
 from ..plyparse import VarType, VarDef, Register, IncrDecr, SymbolName, Dereference, LiteralValue, datatype_of
 from ..datatypes import DataType, REGISTER_BYTES
-from . import CodeError, preserving_registers, to_hex, Context
+from . import CodeError, preserving_registers, to_hex, Context, scoped_name
 
 
 def generate_incrdecr(ctx: Context) -> None:
@@ -139,7 +139,7 @@ def generate_incrdecr(ctx: Context) -> None:
     elif isinstance(target, VarDef):
         if target.vartype == VarType.CONST:
             raise CodeError("cannot modify a constant", target)
-        what_str = target.name
+        what_str = scoped_name(target, scope)
         if target.datatype == DataType.BYTE:
             if stmt.howmuch == 1:
                 out("\v{:s}  {:s}".format("inc" if stmt.operator == "++" else "dec", what_str))
diff --git a/il65/optimize.py b/il65/optimize.py
index dd6b373db..2f422eedf 100644
--- a/il65/optimize.py
+++ b/il65/optimize.py
@@ -203,14 +203,14 @@ class Optimizer:
                             new_assignment = self._make_new_assignment(assignment, 1)
                             assignment.my_scope().replace_node(assignment, new_assignment)
                             self.optimizations_performed = True
-                    if assignment.right.value >= 8 and assignment.operator in ("<<=", ">>="):
+                    elif assignment.right.value >= 8 and assignment.operator in ("<<=", ">>="):
                         print("{}: shifting result is always zero".format(assignment.sourceref))
                         new_stmt = Assignment(sourceref=assignment.sourceref)
                         new_stmt.nodes.append(AssignmentTargets(nodes=[assignment.left], sourceref=assignment.sourceref))
                         new_stmt.nodes.append(LiteralValue(value=0, sourceref=assignment.sourceref))
                         assignment.my_scope().replace_node(assignment, new_stmt)
                         self.optimizations_performed = True
-                    if assignment.operator in ("+=", "-=") and 0 < assignment.right.value < 256:
+                    elif assignment.operator in ("+=", "-=") and 0 < assignment.right.value < 256:
                         howmuch = assignment.right
                         if howmuch.value not in (0, 1):
                             _, howmuch = coerce_constant_value(datatype_of(assignment.left, assignment.my_scope()),
@@ -221,7 +221,7 @@ class Optimizer:
                         new_stmt.target.parent = new_stmt
                         assignment.my_scope().replace_node(assignment, new_stmt)
                         self.optimizations_performed = True
-                    if assignment.right.value == 1 and assignment.operator in ("/=", "//=", "*="):
+                    elif assignment.right.value == 1 and assignment.operator in ("/=", "//=", "*="):
                         self.num_warnings += 1
                         print_warning("{}: removed statement that has no effect".format(assignment.sourceref))
                         assignment.my_scope().remove_node(assignment)
diff --git a/il65/plyparse.py b/il65/plyparse.py
index aa09fdd24..3786d7c05 100644
--- a/il65/plyparse.py
+++ b/il65/plyparse.py
@@ -88,6 +88,9 @@ class AstNode:
 
     def all_nodes(self, *nodetypes: type) -> Generator['AstNode', None, None]:
         nodetypes = nodetypes or (AstNode, )
+        if self.nodes is None:
+            # this is the case when a node has been pruned away
+            return
         child_nodes = list(self.nodes)
         for node in child_nodes:
             if isinstance(node, nodetypes):
@@ -1091,6 +1094,14 @@ def p_block_name(p):
     p[0].scope = p[4]
 
 
+def p_block_address(p):
+    """
+    block :  BITINVERT  INTEGER  endl_opt  scope
+    """
+    p[0] = Block(address=p[2], sourceref=_token_sref(p, 2))
+    p[0].scope = p[4]
+
+
 def p_block(p):
     """
     block :  BITINVERT  endl_opt  scope