Auto merge of rust-lang#125507 - compiler-errors:type-length-limit, r=lcnr

Re-implement a type-size based limit

r? lcnr

This PR reintroduces the type length limit added in rust-lang#37789, which was accidentally made practically useless by the caching changes to `Ty::walk` in rust-lang#72412, which caused the `walk` function to no longer walk over identical elements.

Hitting this length limit is not fatal unless we are in codegen -- so it shouldn't affect passes like the mir inliner which creates potentially very large types (which we observed, for example, when the new trait solver compiles `itertools` in `--release` mode).

This also increases the type length limit from `1048576 == 2 ** 20` to `2 ** 24`, which covers all of the code that can be reached with craterbot-check. Individual crates can increase the length limit further if desired.

Perf regression is mild and I think we should accept it -- reinstating this limit is important for the new trait solver and to make sure we don't accidentally hit more type-size related regressions in the future.

Fixes rust-lang#125460

Author: bors

clippy_lints/src/assigning_clones.rs

@@ -103,7 +103,7 @@ fn extract_call<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) -> Option<
             let args = cx.typeck_results().node_args(expr.hir_id);
 
             // If we could not resolve the method, don't apply the lint
-            let Ok(Some(resolved_method)) = Instance::resolve(cx.tcx, cx.param_env, fn_def_id, args) else {
+            let Ok(Some(resolved_method)) = Instance::try_resolve(cx.tcx, cx.param_env, fn_def_id, args) else {
                 return None;
             };
             if is_trait_method(cx, expr, sym::Clone) && path.ident.name == sym::clone {
@@ -119,7 +119,7 @@ fn extract_call<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) -> Option<
 
             // If we could not resolve the method, don't apply the lint
             let Ok(Some(resolved_method)) = (match kind {
-                ty::FnDef(_, args) => Instance::resolve(cx.tcx, cx.param_env, fn_def_id, args),
+                ty::FnDef(_, args) => Instance::try_resolve(cx.tcx, cx.param_env, fn_def_id, args),
                 _ => Ok(None),
             }) else {
                 return None;

clippy_lints/src/non_copy_const.rs

@@ -293,7 +293,7 @@ impl<'tcx> NonCopyConst<'tcx> {
         ct: ty::UnevaluatedConst<'tcx>,
         span: Span,
     ) -> EvalToValTreeResult<'tcx> {
-        match ty::Instance::resolve(tcx, param_env, ct.def, ct.args) {
+        match ty::Instance::try_resolve(tcx, param_env, ct.def, ct.args) {
             Ok(Some(instance)) => {
                 let cid = GlobalId {
                     instance,