Merge #7062

7062: Add diagnostic for filter_map followed by next r=theotherphil a=theotherphil

Fixes https://github.com/rust-analyzer/rust-analyzer/issues/1725

Co-authored-by: Phil Ellison <[email protected]>

2 files changed, 33 insertions, 3 deletions

diff --git a/crates/ide/src/diagnostics.rs b/crates/ide/src/diagnostics.rs
index b35bc2bae..8607139ba 100644
--- a/crates/ide/src/diagnostics.rs
+++ b/crates/ide/src/diagnostics.rs
@@ -136,6 +136,9 @@ pub(crate) fn diagnostics(
         .on::<hir::diagnostics::IncorrectCase, _>(|d| {
             res.borrow_mut().push(warning_with_fix(d, &sema));
         })
+        .on::<hir::diagnostics::ReplaceFilterMapNextWithFindMap, _>(|d| {
+            res.borrow_mut().push(warning_with_fix(d, &sema));
+        })
         .on::<hir::diagnostics::InactiveCode, _>(|d| {
             // If there's inactive code somewhere in a macro, don't propagate to the call-site.
             if d.display_source().file_id.expansion_info(db).is_some() {
diff --git a/crates/ide/src/diagnostics/fixes.rs b/crates/ide/src/diagnostics/fixes.rs
index 579d5a308..cbfc66ab3 100644
--- a/crates/ide/src/diagnostics/fixes.rs
+++ b/crates/ide/src/diagnostics/fixes.rs
@@ -4,7 +4,7 @@ use hir::{
     db::AstDatabase,
     diagnostics::{
         Diagnostic, IncorrectCase, MissingFields, MissingOkOrSomeInTailExpr, NoSuchField,
-        RemoveThisSemicolon, UnresolvedModule,
+        RemoveThisSemicolon, ReplaceFilterMapNextWithFindMap, UnresolvedModule,
     },
     HasSource, HirDisplay, InFile, Semantics, VariantDef,
 };
@@ -15,8 +15,8 @@ use ide_db::{
 };
 use syntax::{
     algo,
-    ast::{self, edit::IndentLevel, make},
-    AstNode,
+    ast::{self, edit::IndentLevel, make, ArgListOwner},
+    AstNode, TextRange,
 };
 use text_edit::TextEdit;
 
@@ -144,6 +144,33 @@ impl DiagnosticWithFix for IncorrectCase {
     }
 }
 
+impl DiagnosticWithFix for ReplaceFilterMapNextWithFindMap {
+    fn fix(&self, sema: &Semantics<RootDatabase>) -> Option<Fix> {
+        let root = sema.db.parse_or_expand(self.file)?;
+        let next_expr = self.next_expr.to_node(&root);
+        let next_call = ast::MethodCallExpr::cast(next_expr.syntax().clone())?;
+
+        let filter_map_call = ast::MethodCallExpr::cast(next_call.receiver()?.syntax().clone())?;
+        let filter_map_name_range = filter_map_call.name_ref()?.ident_token()?.text_range();
+        let filter_map_args = filter_map_call.arg_list()?;
+
+        let range_to_replace =
+            TextRange::new(filter_map_name_range.start(), next_expr.syntax().text_range().end());
+        let replacement = format!("find_map{}", filter_map_args.syntax().text());
+        let trigger_range = next_expr.syntax().text_range();
+
+        let edit = TextEdit::replace(range_to_replace, replacement);
+
+        let source_change = SourceChange::from_text_edit(self.file.original_file(sema.db), edit);
+
+        Some(Fix::new(
+            "Replace filter_map(..).next() with find_map()",
+            source_change,
+            trigger_range,
+        ))
+    }
+}
+
 fn missing_record_expr_field_fix(
     sema: &Semantics<RootDatabase>,
     usage_file_id: FileId,