Auto merge of rust-lang#12281 - lnicola:increase-overflow-depth, r=lnicola

Increase defalt chalk overflow depth to match max solver size

TBC:

 - rust-lang#12279: ok above 480
 - ~~rust-lang#12182~~
 - ~~rust-lang#12095~~
 - rust-lang#11902: ok above 350
 - ~~rust-lang#11668~~
 - rust-lang#11370: ok above 450
 - rust-lang#9754: probably ok above 250 (!), and the code in cause and branch are gone

Closes rust-lang#12279
Closes rust-lang#11902
Closes rust-lang#11370
Closes rust-lang#9754

Author: bors

crates/hir-ty/src/traits.rs

@@ -27,7 +27,7 @@ pub(crate) struct ChalkContext<'a> {
 
 fn create_chalk_solver() -> chalk_recursive::RecursiveSolver<Interner> {
     let overflow_depth =
-        var("CHALK_OVERFLOW_DEPTH").ok().and_then(|s| s.parse().ok()).unwrap_or(300);
+        var("CHALK_OVERFLOW_DEPTH").ok().and_then(|s| s.parse().ok()).unwrap_or(500);
     let max_size = var("CHALK_SOLVER_MAX_SIZE").ok().and_then(|s| s.parse().ok()).unwrap_or(150);
     chalk_recursive::RecursiveSolver::new(overflow_depth, max_size, Some(Cache::new()))
 }