diff --git a/src/check_expr.cpp b/src/check_expr.cpp
index 6f968c368..aaa6bcabf 100644
--- a/src/check_expr.cpp
+++ b/src/check_expr.cpp
@@ -728,35 +728,38 @@ gb_internal i64 check_distance_between_types(CheckerContext *c, Operand *operand
 			if (operand->mode == Addressing_Constant) {
 				if (check_representable_as_constant(c, operand->value, dst, nullptr)) {
 					if (is_type_typed(dst) && src->kind == Type_Basic) {
+						// NOTE: prefer the untyped constant's default type (int, f64, string, bool,
+						// rune) over other members of the same family, so a call like g(1) picks
+						// `int` over `i64` instead of scoring them identically and going ambiguous.
 						switch (src->Basic.kind) {
 						case Basic_UntypedBool:
 							if (is_type_boolean(dst)) {
-								return 1;
+								return are_types_identical(dst, default_type(src)) ? 1 : 2;
 							}
 							break;
 						case Basic_UntypedRune:
 							if (is_type_integer(dst) || is_type_rune(dst)) {
-								return 1;
+								return are_types_identical(dst, default_type(src)) ? 1 : 2;
 							}
 							break;
 						case Basic_UntypedInteger:
 							if (is_type_integer(dst) || is_type_rune(dst)) {
-								return 1;
+								return are_types_identical(dst, default_type(src)) ? 1 : 2;
 							}
 							break;
 						case Basic_UntypedString:
 							if (is_type_string(dst)) {
-								return 1;
+								return are_types_identical(dst, default_type(src)) ? 1 : 2;
 							}
 							break;
 						case Basic_UntypedFloat:
 							if (is_type_float(dst)) {
-								return 1;
+								return are_types_identical(dst, default_type(src)) ? 1 : 2;
 							}
 							break;
 						case Basic_UntypedComplex:
 							if (is_type_complex(dst)) {
-								return 1;
+								return are_types_identical(dst, default_type(src)) ? 1 : 2;
 							}
 							if (is_type_quaternion(dst)) {
 								return 2;
@@ -764,12 +767,13 @@ gb_internal i64 check_distance_between_types(CheckerContext *c, Operand *operand
 							break;
 						case Basic_UntypedQuaternion:
 							if (is_type_quaternion(dst)) {
-								return 1;
+								return are_types_identical(dst, default_type(src)) ? 1 : 2;
 							}
 							break;
 						}
 					}
-					return 2;
+					// A cross-family constant conversion ranks below a same-family one.
+					return 3;
 				}
 				return -1;
 			}
@@ -7012,6 +7016,11 @@ gb_internal CallArgumentError check_call_arguments_internal(CheckerContext *c, A
 						error(o->expr, "'..' in a variadic procedure can only have one variadic argument at the end");
 					}
 					if (data) {
+						// A synthesised default argument is not evidence of a better match: it
+						// contributes assign_score_function(1) as a dummy bonus and is then scored
+						// again as a perfect-match argument. Discount both, plus 1 to break the
+						// resulting tie, so an exact-arity overload wins.
+						score -= dummy_argument_count * (assign_score_function(0) + assign_score_function(1) + 1);
 						data->score = score;
 						data->result_type = final_proc_type->Proc.results;
 						data->gen_entity = gen_entity;
@@ -7041,6 +7050,11 @@ gb_internal CallArgumentError check_call_arguments_internal(CheckerContext *c, A
 	}
 
 	if (data) {
+		// A synthesised default argument is not evidence of a better match: it
+		// contributes assign_score_function(1) as a dummy bonus and is then scored
+		// again as a perfect-match argument. Discount both, plus 1 to break the
+		// resulting tie, so an exact-arity overload wins.
+		score -= dummy_argument_count * (assign_score_function(0) + assign_score_function(1) + 1);
 		data->score = score;
 		data->result_type = final_proc_type->Proc.results;
 		data->gen_entity = gen_entity;
@@ -7593,8 +7607,10 @@ gb_internal CallArgumentData check_call_arguments_proc_group(CheckerContext *c,
 				array_add(&proc_entities, data.gen_entity);
 				index = proc_entities.count-1;
 
-				// prefer non-polymorphic procedures over polymorphic
-				item.score += assign_score_function(1);
+				// Prefer non-polymorphic procedures over polymorphic. This must be a
+				// small tie-break: assign_score_function(1) is ~a full perfect-match
+				// unit, so adding it made a generic beat an exact concrete overload.
+				item.score -= 1;
 			}
 
 			max_matched_features = gb_max(max_matched_features, matched_target_features(&pt->Proc));