Fix type annotations in ansi fmt

[pimeys]

Motivation

Latest master cannot infer types in the fmt function.

Solution

Tell the compiler the result type. Funnily I couldn't reproduce this directly from tracing repo, but when I have tracing as a dependency following it from github, the later versions would not pass cargo check

We used to be on this version 16fee661ac1f5dd175491e611ff4c08b33c070fa, and cargo update would break the project.

[davidbarsky]

That's a weird one. Sorry about the trouble, but thanks for the fix!

[davidbarsky]

Before I merge, can this be reproduced from https://crates.io/crates/tracing-subscriber/0.2.0-alpha.1?

[pimeys]

diff --git a/query-engine/prisma/Cargo.toml b/query-engine/prisma/Cargo.toml
index 0d84b535..70d43776 100644
--- a/query-engine/prisma/Cargo.toml
+++ b/query-engine/prisma/Cargo.toml
@@ -37,7 +37,7 @@ clap = "2.33"

 tracing = "0.1"
 tracing-log = "0.1"
-tracing-subscriber = { git = "https://github.com/pimeys/tracing", branch = "fix-type-annotations", features = ["json"] }
+tracing-subscriber = { version = "0.2.0-alpha.1", branch = "fix-type-annotations", features = ["json"] }
 tracing-attributes = "0.1"
 log = "0.4"

   Compiling prisma v0.1.0 (/home/pimeys/code/prisma-engine/query-engine/prisma)
   Compiling tracing-subscriber v0.2.0-alpha.1
   Compiling query-core v0.1.0 (/home/pimeys/code/prisma-engine/query-engine/core)
error[E0282]: type annotations needed
   --> /home/pimeys/.cargo/registry/src/jackfan.us.kg-1ecc6299db9ec823/tracing-subscriber-0.2.0-alpha.1/src/fmt/format/mod.rs:513:9
    |
513 | /         self.ctx.visit_spans(|span| {
514 | |             if seen {
515 | |                 f.pad(":")?;
516 | |             }
...   |
526 | |             Ok(())
527 | |         })?;
    | |___________^ cannot infer type

error: aborting due to previous error

[pimeys]

Yeah super weird... Although sometimes you get weird errors with a super generic codebase, although this is new to me too...