Merge #2489

2489: Implement `format_args` r=flodiebold a=flodiebold

This fixes a huge amount of type mismatches (because every format call was a type mismatch so far); I also hoped to get go to def working within `format!` etc., and the test says it should, but in practice it still doesn't seem to...

Also remove the `len` parameter from `Name::new_inline_ascii`, which I'm assuming was only there because of `const fn` limitations?

cc @edwin0cheng 

Co-authored-by: Florian Diebold <[email protected]>

1 files changed, 30 insertions, 0 deletions

diff --git a/crates/ra_ide/src/goto_definition.rs b/crates/ra_ide/src/goto_definition.rs
index 76a741207..d3c198813 100644
--- a/crates/ra_ide/src/goto_definition.rs
+++ b/crates/ra_ide/src/goto_definition.rs
@@ -689,8 +689,38 @@ mod tests {
                     fo<|>o();
                 }
             }
+            mod confuse_index { fn foo(); }
             ",
             "foo FN_DEF FileId(1) [52; 63) [55; 58)",
         );
     }
+
+    #[should_panic] // currently failing because of expr mapping problems
+    #[test]
+    fn goto_through_format() {
+        check_goto(
+            "
+            //- /lib.rs
+            #[macro_export]
+            macro_rules! format {
+                ($($arg:tt)*) => ($crate::fmt::format($crate::__export::format_args!($($arg)*)))
+            }
+            #[rustc_builtin_macro]
+            #[macro_export]
+            macro_rules! format_args {
+                ($fmt:expr) => ({ /* compiler built-in */ });
+                ($fmt:expr, $($args:tt)*) => ({ /* compiler built-in */ })
+            }
+            pub mod __export {
+                pub use crate::format_args;
+                fn foo() {} // for index confusion
+            }
+            fn foo() -> i8 {}
+            fn test() {
+                format!(\"{}\", fo<|>o())
+            }
+            ",
+            "foo FN_DEF FileId(1) [359; 376) [362; 365)",
+        );
+    }
 }