remove undefined global constraint

compiler/checker/checker.odin

@@ -7891,7 +7891,7 @@ build_compound_expr :: proc(
 		id := source.add(
 			checker.diagnostics,
 			expr.span,
-			"'undefined' is only valid as a mutable local declaration initializer",
+			"'undefined' is only valid as a mutable declaration initializer",
 		)
 		return invalid_hir_expr(checker, expr.span, id, expected)
 	case .Enum_Literal:
@@ -13686,7 +13686,20 @@ build_globals :: proc(checker: ^Checker) {
 		          is_runtime_type(checker, checker.global_types[global_index]) {
 			expected = checker.global_types[global_index]
 		}
-		expr := build_expr(checker, global.expr, nil, &dependencies, &calls, expected, global.pkg, global.file)
+		expr := hir.INVALID_EXPR
+		if !global.immutable && is_undefined_expr(checker, global.expr) {
+			expr = add_hir_expr(checker, hir.Expr{
+				kind=.Undefined,
+				span=checker.ast_module.exprs[global.expr].span,
+				type=checker.global_types[global_index],
+				target=hir.INVALID_REF,
+				left=hir.INVALID_EXPR,
+				right=hir.INVALID_EXPR,
+				diagnostic=source.INVALID_DIAGNOSTIC,
+			})
+		} else {
+			expr = build_expr(checker, global.expr, nil, &dependencies, &calls, expected, global.pkg, global.file)
+		}
 		global_type := checker.global_types[global_index]
 		if is_runtime_type(checker, checker.global_types[global_index]) {
 			expr = coerce_expr(checker, expr, checker.global_types[global_index], global.span)
@@ -13713,17 +13726,6 @@ build_globals :: proc(checker: ^Checker) {
 			global_type = constraint_recovery_type(checker, declared)
 			expr = invalid_hir_expr(checker, global.span, diagnostic, global_type)
 		}
-		if !global.immutable && is_undefined_expr(checker, global.expr) {
-			diagnostic = source.add(
-				checker.diagnostics,
-				global.span,
-				"'undefined' is only valid as a mutable local declaration initializer",
-			)
-			if !is_runtime_type(checker, global_type) {
-				global_type = types.I64
-			}
-			expr = invalid_hir_expr(checker, global.span, diagnostic, global_type)
-		}
 		if diagnostic == source.INVALID_DIAGNOSTIC && !is_runtime_type(checker, global_type) {
 			if types.is_comptime_only(global_type, &checker.module.types) ||
 			   types.is_comptime_only(declared, &checker.module.types) {