Rollup merge of #107102 - compiler-errors:new-solver-new-candidats-4, r=lcnr

Implement some more predicates in the new solver

Implement a few more goals. The subtype goal specifically is important, since it's required for this code to compile:

```
fn main() {
  let mut x = vec![];
  x.push(1i32);
}
```

(I think we emit a subtype goal here because of coercion).

Drive-by: Also implements `--compare-mode=next-solver` -- I've been using this locally a lot to find out what works and what doesn't. I'm also happy to split this out into another PR.

r? `@lcnr`

3 files changed, 7 insertions, 0 deletions

diff --git a/src/tools/compiletest/src/common.rs b/src/tools/compiletest/src/common.rs
index a5f5eb447da..3676f69b100 100644
--- a/src/tools/compiletest/src/common.rs
+++ b/src/tools/compiletest/src/common.rs
@@ -123,6 +123,7 @@ pub enum FailMode {
 pub enum CompareMode {
     Polonius,
     Chalk,
+    NextSolver,
     SplitDwarf,
     SplitDwarfSingle,
 }
@@ -132,6 +133,7 @@ impl CompareMode {
         match *self {
             CompareMode::Polonius => "polonius",
             CompareMode::Chalk => "chalk",
+            CompareMode::NextSolver => "next-solver",
             CompareMode::SplitDwarf => "split-dwarf",
             CompareMode::SplitDwarfSingle => "split-dwarf-single",
         }
@@ -141,6 +143,7 @@ impl CompareMode {
         match s.as_str() {
             "polonius" => CompareMode::Polonius,
             "chalk" => CompareMode::Chalk,
+            "next-solver" => CompareMode::NextSolver,
             "split-dwarf" => CompareMode::SplitDwarf,
             "split-dwarf-single" => CompareMode::SplitDwarfSingle,
             x => panic!("unknown --compare-mode option: {}", x),
diff --git a/src/tools/compiletest/src/header.rs b/src/tools/compiletest/src/header.rs
index 423299495a2..dc30e4bb1be 100644
--- a/src/tools/compiletest/src/header.rs
+++ b/src/tools/compiletest/src/header.rs
@@ -710,6 +710,7 @@ impl Config {
             match self.compare_mode {
                 Some(CompareMode::Polonius) => name == "compare-mode-polonius",
                 Some(CompareMode::Chalk) => name == "compare-mode-chalk",
+                Some(CompareMode::NextSolver) => name == "compare-mode-next-solver",
                 Some(CompareMode::SplitDwarf) => name == "compare-mode-split-dwarf",
                 Some(CompareMode::SplitDwarfSingle) => name == "compare-mode-split-dwarf-single",
                 None => false,
diff --git a/src/tools/compiletest/src/runtest.rs b/src/tools/compiletest/src/runtest.rs
index 859c0f1da06..51c9a27c83d 100644
--- a/src/tools/compiletest/src/runtest.rs
+++ b/src/tools/compiletest/src/runtest.rs
@@ -2030,6 +2030,9 @@ impl<'test> TestCx<'test> {
             Some(CompareMode::Chalk) => {
                 rustc.args(&["-Ztrait-solver=chalk"]);
             }
+            Some(CompareMode::NextSolver) => {
+                rustc.args(&["-Ztrait-solver=next"]);
+            }
             Some(CompareMode::SplitDwarf) if self.config.target.contains("windows") => {
                 rustc.args(&["-Csplit-debuginfo=unpacked", "-Zunstable-options"]);
             }