diff --git a/artiq/compiler/transforms/artiq_ir_generator.py b/artiq/compiler/transforms/artiq_ir_generator.py
index b0ce78c91..a822f8815 100644
--- a/artiq/compiler/transforms/artiq_ir_generator.py
+++ b/artiq/compiler/transforms/artiq_ir_generator.py
@@ -186,7 +186,7 @@ class ARTIQIRGenerator(algorithm.Visitor):
                 optargs.append(ir.Argument(ir.TOption(typ.optargs[arg_name]), "arg." + arg_name))
 
             func = ir.Function(typ, ".".join(self.name), [env_arg] + args + optargs,
-                               loc=node.keyword_loc)
+                               loc=node.lambda_loc if is_lambda else node.keyword_loc)
             func.is_internal = is_internal
             self.functions.append(func)
             old_func, self.current_function = self.current_function, func
diff --git a/artiq/compiler/transforms/inferencer.py b/artiq/compiler/transforms/inferencer.py
index a256f9775..0fe000189 100644
--- a/artiq/compiler/transforms/inferencer.py
+++ b/artiq/compiler/transforms/inferencer.py
@@ -728,7 +728,7 @@ class Inferencer(algorithm.Visitor):
             elif keyword.arg in typ.optargs:
                 self._unify(keyword.value.type, typ.optargs[keyword.arg],
                             keyword.value.loc, None)
-            passed_args.add(keyword.arg)
+            passed_args[keyword.arg] = keyword.arg_loc
 
         for formalname in typ.args:
             if formalname not in passed_args:
diff --git a/artiq/compiler/transforms/llvm_ir_generator.py b/artiq/compiler/transforms/llvm_ir_generator.py
index 4eaf34e68..4fd341763 100644
--- a/artiq/compiler/transforms/llvm_ir_generator.py
+++ b/artiq/compiler/transforms/llvm_ir_generator.py
@@ -403,7 +403,7 @@ class LLVMIRGenerator:
         finally:
             self.llfunction = None
             self.llmap = {}
-            self.llphis = []
+            self.phis = []
 
     def process_Phi(self, insn):
         llinsn = self.llbuilder.phi(self.llty_of_type(insn.type), name=insn.name)
diff --git a/lit-test/test/inferencer/error_builtin_calls.py b/lit-test/test/inferencer/error_builtin_calls.py
index 32ce8b294..8eab7a203 100644
--- a/lit-test/test/inferencer/error_builtin_calls.py
+++ b/lit-test/test/inferencer/error_builtin_calls.py
@@ -11,5 +11,5 @@ len(1)
 # CHECK-L: ${LINE:+1}: error: the argument of list() must be of an iterable type
 list(1)
 
-# CHECK-L: ${LINE:+1}: error: an argument of range() must be of a numeric type
+# CHECK-L: ${LINE:+1}: error: an argument of range() must be of an integer type
 range([])
diff --git a/lit-test/test/inferencer/error_call.py b/lit-test/test/inferencer/error_call.py
index 21ba5bdf6..739ffa249 100644
--- a/lit-test/test/inferencer/error_call.py
+++ b/lit-test/test/inferencer/error_call.py
@@ -13,7 +13,7 @@ f(*[])
 # CHECK-L: ${LINE:+1}: error: variadic arguments are not supported
 f(**[])
 
-# CHECK-L: ${LINE:+1}: error: the argument 'x' is already passed
+# CHECK-L: ${LINE:+1}: error: the argument 'x' has been passed earlier as positional
 f(1, x=1)
 
 # CHECK-L: ${LINE:+1}: error: mandatory argument 'x' is not passed