Add basic support for array lengths in types

This recognizes `let a = [1u8, 2, 3]` as having type `[u8; 3]` instead
of the previous `[u8; _]`. Byte strings and `[0u8; 2]` kinds of range
array declarations are unsupported as before.

I don't know why a bunch of our rustc tests had single quotes inside
strings un-escaped by `UPDATE_EXPECT=1 cargo t`, but I don't think it's
bad? Maybe something in a nightly?

1 files changed, 3 insertions, 3 deletions

diff --git a/crates/hir_ty/src/tests/patterns.rs b/crates/hir_ty/src/tests/patterns.rs
index f514b3efe..33305f208 100644
--- a/crates/hir_ty/src/tests/patterns.rs
+++ b/crates/hir_ty/src/tests/patterns.rs
@@ -243,8 +243,8 @@ fn infer_pattern_match_slice() {
         expect![[r#"
             10..209 '{     ...   } }': ()
             20..25 'slice': &[f64]
-            36..42 '&[0.0]': &[f64; _]
-            37..42 '[0.0]': [f64; _]
+            36..42 '&[0.0]': &[f64; 1]
+            37..42 '[0.0]': [f64; 1]
             38..41 '0.0': f64
             48..207 'match ...     }': ()
             54..59 'slice': &[f64]
@@ -346,7 +346,7 @@ fn infer_pattern_match_arr() {
         expect![[r#"
             10..179 '{     ...   } }': ()
             20..23 'arr': [f64; _]
-            36..46 '[0.0, 1.0]': [f64; _]
+            36..46 '[0.0, 1.0]': [f64; 2]
             37..40 '0.0': f64
             42..45 '1.0': f64
             52..177 'match ...     }': ()