diff --git a/loopy/codegen/instruction.py b/loopy/codegen/instruction.py
index 0970fa5c4298061fc82e3d8ea1cf2b8460c3fb10..ecb500d901e7e101d78711e7ea22cb0dcd81c1d8 100644
--- a/loopy/codegen/instruction.py
+++ b/loopy/codegen/instruction.py
@@ -9,8 +9,19 @@ def generate_instruction_code(kernel, insn, codegen_state):
 
     ccm = codegen_state.c_code_mapper
 
+    expr = insn.expression
+
+    if ccm.allow_complex:
+        # detect widen-to-complex in assignment, account for it.
+        expr_dtype = ccm.infer_type(expr)
+        var_dtype = kernel.get_var_descriptor(insn.get_assignee_var_name()).dtype
+
+        if var_dtype.kind == "c" and expr_dtype.kind != "c":
+            from pymbolic import var
+            expr = var("%s_fromreal" % ccm.complex_type_name(var_dtype))(expr)
+
     from cgen import Assign
-    insn_code = Assign(ccm(insn.assignee), ccm(insn.expression))
+    insn_code = Assign(ccm(insn.assignee), ccm(expr))
     from loopy.codegen.bounds import wrap_in_bounds_checks
     insn_code, impl_domain = wrap_in_bounds_checks(
             ccm, kernel.domain, kernel.insn_inames(insn),