Append .0 to unsuffixed float if it would otherwise become int token

Author: dtolnay

library/proc_macro/src/lib.rs

@@ -1074,7 +1074,11 @@ impl Literal {
         if !n.is_finite() {
             panic!("Invalid float literal {}", n);
         }
-        Literal(bridge::client::Literal::float(&n.to_string()))
+        let mut repr = n.to_string();
+        if !repr.contains('.') {
+            repr.push_str(".0");
+        }
+        Literal(bridge::client::Literal::float(&repr))
     }
 
     /// Creates a new suffixed floating-point literal.
@@ -1115,7 +1119,11 @@ impl Literal {
         if !n.is_finite() {
             panic!("Invalid float literal {}", n);
         }
-        Literal(bridge::client::Literal::float(&n.to_string()))
+        let mut repr = n.to_string();
+        if !repr.contains('.') {
+            repr.push_str(".0");
+        }
+        Literal(bridge::client::Literal::float(&repr))
     }
 
     /// Creates a new suffixed floating-point literal.

src/test/ui/proc-macro/auxiliary/api/parse.rs

@@ -8,6 +8,10 @@ pub fn test() {
 fn test_display_literal() {
     assert_eq!(Literal::isize_unsuffixed(-10).to_string(), "-10");
     assert_eq!(Literal::isize_suffixed(-10).to_string(), "-10isize");
+    assert_eq!(Literal::f32_unsuffixed(-10.0).to_string(), "-10.0");
+    assert_eq!(Literal::f32_suffixed(-10.0).to_string(), "-10f32");
+    assert_eq!(Literal::f64_unsuffixed(-10.0).to_string(), "-10.0");
+    assert_eq!(Literal::f64_suffixed(-10.0).to_string(), "-10f64");
 }
 
 fn test_parse_literal() {