diff --git a/crates/hir-def/src/body/pretty.rs b/crates/hir-def/src/body/pretty.rs
index 9aff712f4c..16e409dfe6 100644
--- a/crates/hir-def/src/body/pretty.rs
+++ b/crates/hir-def/src/body/pretty.rs
@@ -69,7 +69,9 @@ pub(super) fn print_body_hir(db: &dyn DefDatabase, body: &Body, owner: DefWithBo
             p.buf.push(' ');
         });
         // remove the last ", " in param list
-        p.buf.truncate(p.buf.len() - 2);
+        if body.params.len() > 0 {
+            p.buf.truncate(p.buf.len() - 2);
+        }
         p.buf.push(')');
         p.buf.push(' ');
         // return type
diff --git a/crates/hir-def/src/body/tests.rs b/crates/hir-def/src/body/tests.rs
index e8b26d5373..0011d3a20c 100644
--- a/crates/hir-def/src/body/tests.rs
+++ b/crates/hir-def/src/body/tests.rs
@@ -156,7 +156,7 @@ fn main() {
     );
 
     expect![[r#"
-        fn main() {
+        fn main() -> () {
             let are = "are";
             let count = 10;
             builtin#lang(Arguments::new_v1_formatted)(
@@ -258,7 +258,7 @@ impl SsrError {
 
     assert_eq!(db.body_with_source_map(def).1.diagnostics(), &[]);
     expect![[r#"
-        fn main() {
+        fn main() -> () {
             _ = $crate::error::SsrError::new(
                 builtin#lang(Arguments::new_v1_formatted)(
                     &[
@@ -303,7 +303,7 @@ macro_rules! m {
     };
 }
 
-fn f() {
+fn f(a: i32, b: u32) -> String {
     m!();
 }
 "#,
@@ -317,7 +317,7 @@ fn f() {
     }
 
     expect![[r#"
-        fn f() {
+        fn f(a: i32, b: u32) -> String {
             {
                 $crate::panicking::panic_fmt(
                     builtin#lang(Arguments::new_v1_formatted)(