Merge #8813

8813: Get some more array lengths! r=lf- a=lf-

This is built on #8799 and thus contains its changes. I'll rebase it onto master when that one gets merged. It adds support for r-a understanding the length of:

* `let a: [u8; 2] = ...`
* `let a = b"aaa"`
* `let a = [0u8; 4]`

I have added support for getting the values of byte strings, which was not previously there. I am least confident in the correctness of this part and it probably needs some more tests, as we currently have only one test that exercised that part (!).

Fixes #2922.

Co-authored-by: Jade <[email protected]>

3 files changed, 30 insertions, 2 deletions

diff --git a/crates/ide_assists/src/handlers/add_explicit_type.rs b/crates/ide_assists/src/handlers/add_explicit_type.rs
index 62db31952..36589203d 100644
--- a/crates/ide_assists/src/handlers/add_explicit_type.rs
+++ b/crates/ide_assists/src/handlers/add_explicit_type.rs
@@ -198,6 +198,34 @@ fn main() {
         )
     }
 
+    /// https://github.com/rust-analyzer/rust-analyzer/issues/2922
+    #[test]
+    fn regression_issue_2922() {
+        check_assist(
+            add_explicit_type,
+            r#"
+fn main() {
+    let $0v = [0.0; 2];
+}
+"#,
+            r#"
+fn main() {
+    let v: [f64; 2] = [0.0; 2];
+}
+"#,
+        );
+        // note: this may break later if we add more consteval. it just needs to be something that our
+        // consteval engine doesn't understand
+        check_assist_not_applicable(
+            add_explicit_type,
+            r#"
+fn main() {
+    let $0l = [0.0; 2+2];
+}
+"#,
+        );
+    }
+
     #[test]
     fn default_generics_should_not_be_added() {
         check_assist(
diff --git a/crates/ide_assists/src/handlers/raw_string.rs b/crates/ide_assists/src/handlers/raw_string.rs
index d0f1613f3..d98a55ae4 100644
--- a/crates/ide_assists/src/handlers/raw_string.rs
+++ b/crates/ide_assists/src/handlers/raw_string.rs
@@ -1,6 +1,6 @@
 use std::borrow::Cow;
 
-use syntax::{ast, AstToken, TextRange, TextSize};
+use syntax::{ast, ast::IsString, AstToken, TextRange, TextSize};
 
 use crate::{AssistContext, AssistId, AssistKind, Assists};
 
diff --git a/crates/ide_assists/src/handlers/replace_string_with_char.rs b/crates/ide_assists/src/handlers/replace_string_with_char.rs
index 634b9c0b7..0800d291e 100644
--- a/crates/ide_assists/src/handlers/replace_string_with_char.rs
+++ b/crates/ide_assists/src/handlers/replace_string_with_char.rs
@@ -1,4 +1,4 @@
-use syntax::{ast, AstToken, SyntaxKind::STRING};
+use syntax::{ast, ast::IsString, AstToken, SyntaxKind::STRING};
 
 use crate::{AssistContext, AssistId, AssistKind, Assists};