Auto merge of rust-lang#16723 - norskeld:constants-autocomplete, r=Veykril

fix: autocomplete constants inside format strings

Hi! This PR adds autocompletion for constants (including statics) inside format strings and closes rust-lang#16608.

I'm not sure about adding the `constants` field to the `CompletionContext`. It kinda makes sense, since it's in line with the `locals` field, and this way everything looks a bit cleaner, but at the same time does it really need to be there?

Anyway, let me know if anything should/can be changed. :)

Author: bors

crates/ide-completion/src/completions/format_string.rs

@@ -1,6 +1,7 @@
 //! Completes identifiers in format string literals.
 
-use ide_db::syntax_helpers::format_string::is_format_string;
+use hir::{ModuleDef, ScopeDef};
+use ide_db::{syntax_helpers::format_string::is_format_string, SymbolKind};
 use itertools::Itertools;
 use syntax::{ast, AstToken, TextRange, TextSize};
 
@@ -33,7 +34,23 @@ pub(crate) fn format_string(
     ctx.locals.iter().for_each(|(name, _)| {
         CompletionItem::new(CompletionItemKind::Binding, source_range, name.to_smol_str())
             .add_to(acc, ctx.db);
-    })
+    });
+    ctx.scope.process_all_names(&mut |name, scope| {
+        if let ScopeDef::ModuleDef(module_def) = scope {
+            let symbol_kind = match module_def {
+                ModuleDef::Const(..) => SymbolKind::Const,
+                ModuleDef::Static(..) => SymbolKind::Static,
+                _ => return,
+            };
+
+            CompletionItem::new(
+                CompletionItemKind::SymbolKind(symbol_kind),
+                source_range,
+                name.to_smol_str(),
+            )
+            .add_to(acc, ctx.db);
+        }
+    });
 }
 
 #[cfg(test)]
@@ -110,6 +127,80 @@ fn main() {
     let foobar = 1;
     format_args!("{foobar");
 }
+"#,
+        );
+    }
+
+    #[test]
+    fn completes_constants() {
+        check_edit(
+            "FOOBAR",
+            r#"
+//- minicore: fmt
+fn main() {
+    const FOOBAR: usize = 42;
+    format_args!("{f$0");
+}
+"#,
+            r#"
+fn main() {
+    const FOOBAR: usize = 42;
+    format_args!("{FOOBAR");
+}
+"#,
+        );
+
+        check_edit(
+            "FOOBAR",
+            r#"
+//- minicore: fmt
+fn main() {
+    const FOOBAR: usize = 42;
+    format_args!("{$0");
+}
+"#,
+            r#"
+fn main() {
+    const FOOBAR: usize = 42;
+    format_args!("{FOOBAR");
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn completes_static_constants() {
+        check_edit(
+            "FOOBAR",
+            r#"
+//- minicore: fmt
+fn main() {
+    static FOOBAR: usize = 42;
+    format_args!("{f$0");
+}
+"#,
+            r#"
+fn main() {
+    static FOOBAR: usize = 42;
+    format_args!("{FOOBAR");
+}
+"#,
+        );
+
+        check_edit(
+            "FOOBAR",
+            r#"
+//- minicore: fmt
+fn main() {
+    static FOOBAR: usize = 42;
+    format_args!("{$0");
+}
+"#,
+            r#"
+fn main() {
+    static FOOBAR: usize = 42;
+    format_args!("{FOOBAR");
+}
 "#,
         );
     }