diff --git a/crates/hir/src/diagnostics.rs b/crates/hir/src/diagnostics.rs index 447faa04f189..5343a036c019 100644 --- a/crates/hir/src/diagnostics.rs +++ b/crates/hir/src/diagnostics.rs @@ -5,5 +5,5 @@ pub use hir_expand::diagnostics::{ }; pub use hir_ty::diagnostics::{ IncorrectCase, MismatchedArgCount, MissingFields, MissingMatchArms, MissingOkOrSomeInTailExpr, - NoSuchField, RemoveThisSemicolon, + NoSuchField, RemoveThisSemicolon, ReplaceFilterMapNextWithFindMap, }; diff --git a/crates/hir_def/src/path.rs b/crates/hir_def/src/path.rs index e34cd7f2f288..84ea09b5387b 100644 --- a/crates/hir_def/src/path.rs +++ b/crates/hir_def/src/path.rs @@ -304,6 +304,7 @@ pub use hir_expand::name as __name; #[macro_export] macro_rules! __known_path { (core::iter::IntoIterator) => {}; + (core::iter::Iterator) => {}; (core::result::Result) => {}; (core::option::Option) => {}; (core::ops::Range) => {}; diff --git a/crates/hir_expand/src/name.rs b/crates/hir_expand/src/name.rs index d692cec145a1..c7609e90d980 100644 --- a/crates/hir_expand/src/name.rs +++ b/crates/hir_expand/src/name.rs @@ -186,6 +186,9 @@ pub mod known { Neg, Not, Index, + // Components of known path (function name) + filter_map, + next, // Builtin macros file, column, diff --git a/crates/hir_ty/src/diagnostics.rs b/crates/hir_ty/src/diagnostics.rs index 247da43f22d1..323c5f96308e 100644 --- a/crates/hir_ty/src/diagnostics.rs +++ b/crates/hir_ty/src/diagnostics.rs @@ -247,7 +247,7 @@ impl Diagnostic for RemoveThisSemicolon { // Diagnostic: break-outside-of-loop // -// This diagnostic is triggered if `break` keyword is used outside of a loop. +// This diagnostic is triggered if the `break` keyword is used outside of a loop. #[derive(Debug)] pub struct BreakOutsideOfLoop { pub file: HirFileId, @@ -271,7 +271,7 @@ impl Diagnostic for BreakOutsideOfLoop { // Diagnostic: missing-unsafe // -// This diagnostic is triggered if operation marked as `unsafe` is used outside of `unsafe` function or block. +// This diagnostic is triggered if an operation marked as `unsafe` is used outside of an `unsafe` function or block. #[derive(Debug)] pub struct MissingUnsafe { pub file: HirFileId, @@ -295,7 +295,7 @@ impl Diagnostic for MissingUnsafe { // Diagnostic: mismatched-arg-count // -// This diagnostic is triggered if function is invoked with an incorrect amount of arguments. +// This diagnostic is triggered if a function is invoked with an incorrect amount of arguments. #[derive(Debug)] pub struct MismatchedArgCount { pub file: HirFileId, @@ -347,7 +347,7 @@ impl fmt::Display for CaseType { // Diagnostic: incorrect-ident-case // -// This diagnostic is triggered if item name doesn't follow https://doc.rust-lang.org/1.0.0/style/style/naming/README.html[Rust naming convention]. +// This diagnostic is triggered if an item name doesn't follow https://doc.rust-lang.org/1.0.0/style/style/naming/README.html[Rust naming convention]. #[derive(Debug)] pub struct IncorrectCase { pub file: HirFileId, @@ -386,6 +386,31 @@ impl Diagnostic for IncorrectCase { } } +// Diagnostic: replace-filter-map-next-with-find-map +// +// This diagnostic is triggered when `.filter_map(..).next()` is used, rather than the more concise `.find_map(..)`. +#[derive(Debug)] +pub struct ReplaceFilterMapNextWithFindMap { + pub file: HirFileId, + /// This expression is the whole method chain up to and including `.filter_map(..).next()`. + pub next_expr: AstPtr, +} + +impl Diagnostic for ReplaceFilterMapNextWithFindMap { + fn code(&self) -> DiagnosticCode { + DiagnosticCode("replace-filter-map-next-with-find-map") + } + fn message(&self) -> String { + "replace filter_map(..).next() with find_map(..)".to_string() + } + fn display_source(&self) -> InFile { + InFile { file_id: self.file, value: self.next_expr.clone().into() } + } + fn as_any(&self) -> &(dyn Any + Send + 'static) { + self + } +} + #[cfg(test)] mod tests { use base_db::{fixture::WithFixture, FileId, SourceDatabase, SourceDatabaseExt}; @@ -644,4 +669,87 @@ fn foo() { break; } "#, ); } + + // Register the required standard library types to make the tests work + fn add_filter_map_with_find_next_boilerplate(body: &str) -> String { + let prefix = r#" + //- /main.rs crate:main deps:core + use core::iter::Iterator; + use core::option::Option::{self, Some, None}; + "#; + let suffix = r#" + //- /core/lib.rs crate:core + pub mod option { + pub enum Option { Some(T), None } + } + pub mod iter { + pub trait Iterator { + type Item; + fn filter_map(self, f: F) -> FilterMap where F: FnMut(Self::Item) -> Option { FilterMap } + fn next(&mut self) -> Option; + } + pub struct FilterMap {} + impl Iterator for FilterMap { + type Item = i32; + fn next(&mut self) -> i32 { 7 } + } + } + "#; + format!("{}{}{}", prefix, body, suffix) + } + + #[test] + fn replace_filter_map_next_with_find_map2() { + check_diagnostics(&add_filter_map_with_find_next_boilerplate( + r#" + fn foo() { + let m = [1, 2, 3].iter().filter_map(|x| if *x == 2 { Some (4) } else { None }).next(); + //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ replace filter_map(..).next() with find_map(..) + } + "#, + )); + } + + #[test] + fn replace_filter_map_next_with_find_map_no_diagnostic_without_next() { + check_diagnostics(&add_filter_map_with_find_next_boilerplate( + r#" + fn foo() { + let m = [1, 2, 3] + .iter() + .filter_map(|x| if *x == 2 { Some (4) } else { None }) + .len(); + } + "#, + )); + } + + #[test] + fn replace_filter_map_next_with_find_map_no_diagnostic_with_intervening_methods() { + check_diagnostics(&add_filter_map_with_find_next_boilerplate( + r#" + fn foo() { + let m = [1, 2, 3] + .iter() + .filter_map(|x| if *x == 2 { Some (4) } else { None }) + .map(|x| x + 2) + .len(); + } + "#, + )); + } + + #[test] + fn replace_filter_map_next_with_find_map_no_diagnostic_if_not_in_chain() { + check_diagnostics(&add_filter_map_with_find_next_boilerplate( + r#" + fn foo() { + let m = [1, 2, 3] + .iter() + .filter_map(|x| if *x == 2 { Some (4) } else { None }); + let n = m.next(); + } + "#, + )); + } } diff --git a/crates/hir_ty/src/diagnostics/expr.rs b/crates/hir_ty/src/diagnostics/expr.rs index 107417c27809..d740b7265554 100644 --- a/crates/hir_ty/src/diagnostics/expr.rs +++ b/crates/hir_ty/src/diagnostics/expr.rs @@ -2,8 +2,10 @@ use std::sync::Arc; -use hir_def::{expr::Statement, path::path, resolver::HasResolver, AdtId, DefWithBodyId}; -use hir_expand::diagnostics::DiagnosticSink; +use hir_def::{ + expr::Statement, path::path, resolver::HasResolver, AdtId, AssocItemId, DefWithBodyId, +}; +use hir_expand::{diagnostics::DiagnosticSink, name}; use rustc_hash::FxHashSet; use syntax::{ast, AstPtr}; @@ -24,6 +26,8 @@ pub(crate) use hir_def::{ LocalFieldId, VariantId, }; +use super::ReplaceFilterMapNextWithFindMap; + pub(super) struct ExprValidator<'a, 'b: 'a> { owner: DefWithBodyId, infer: Arc, @@ -40,6 +44,8 @@ impl<'a, 'b> ExprValidator<'a, 'b> { } pub(super) fn validate_body(&mut self, db: &dyn HirDatabase) { + self.check_for_filter_map_next(db); + let body = db.body(self.owner.into()); for (id, expr) in body.exprs.iter() { @@ -150,20 +156,76 @@ impl<'a, 'b> ExprValidator<'a, 'b> { } } - fn validate_call(&mut self, db: &dyn HirDatabase, call_id: ExprId, expr: &Expr) -> Option<()> { + fn check_for_filter_map_next(&mut self, db: &dyn HirDatabase) { + // Find the FunctionIds for Iterator::filter_map and Iterator::next + let iterator_path = path![core::iter::Iterator]; + let resolver = self.owner.resolver(db.upcast()); + let iterator_trait_id = match resolver.resolve_known_trait(db.upcast(), &iterator_path) { + Some(id) => id, + None => return, + }; + let iterator_trait_items = &db.trait_data(iterator_trait_id).items; + let filter_map_function_id = + match iterator_trait_items.iter().find(|item| item.0 == name![filter_map]) { + Some((_, AssocItemId::FunctionId(id))) => id, + _ => return, + }; + let next_function_id = match iterator_trait_items.iter().find(|item| item.0 == name![next]) + { + Some((_, AssocItemId::FunctionId(id))) => id, + _ => return, + }; + + // Search function body for instances of .filter_map(..).next() + let body = db.body(self.owner.into()); + let mut prev = None; + for (id, expr) in body.exprs.iter() { + if let Expr::MethodCall { receiver, .. } = expr { + let function_id = match self.infer.method_resolution(id) { + Some(id) => id, + None => continue, + }; + + if function_id == *filter_map_function_id { + prev = Some(id); + continue; + } + + if function_id == *next_function_id { + if let Some(filter_map_id) = prev { + if *receiver == filter_map_id { + let (_, source_map) = db.body_with_source_map(self.owner.into()); + if let Ok(next_source_ptr) = source_map.expr_syntax(id) { + self.sink.push(ReplaceFilterMapNextWithFindMap { + file: next_source_ptr.file_id, + next_expr: next_source_ptr.value, + }); + } + } + } + } + } + prev = None; + } + } + + fn validate_call(&mut self, db: &dyn HirDatabase, call_id: ExprId, expr: &Expr) { // Check that the number of arguments matches the number of parameters. // FIXME: Due to shortcomings in the current type system implementation, only emit this // diagnostic if there are no type mismatches in the containing function. if self.infer.type_mismatches.iter().next().is_some() { - return None; + return; } let is_method_call = matches!(expr, Expr::MethodCall { .. }); let (sig, args) = match expr { Expr::Call { callee, args } => { let callee = &self.infer.type_of_expr[*callee]; - let sig = callee.callable_sig(db)?; + let sig = match callee.callable_sig(db) { + Some(sig) => sig, + None => return, + }; (sig, args.clone()) } Expr::MethodCall { receiver, args, .. } => { @@ -175,22 +237,25 @@ impl<'a, 'b> ExprValidator<'a, 'b> { // if the receiver is of unknown type, it's very likely we // don't know enough to correctly resolve the method call. // This is kind of a band-aid for #6975. - return None; + return; } // FIXME: note that we erase information about substs here. This // is not right, but, luckily, doesn't matter as we care only // about the number of params - let callee = self.infer.method_resolution(call_id)?; + let callee = match self.infer.method_resolution(call_id) { + Some(callee) => callee, + None => return, + }; let sig = db.callable_item_signature(callee.into()).value; (sig, args) } - _ => return None, + _ => return, }; if sig.is_varargs { - return None; + return; } let params = sig.params(); @@ -213,8 +278,6 @@ impl<'a, 'b> ExprValidator<'a, 'b> { }); } } - - None } fn validate_match( diff --git a/crates/ide/src/diagnostics.rs b/crates/ide/src/diagnostics.rs index b35bc2bae22f..8607139ba3cb 100644 --- a/crates/ide/src/diagnostics.rs +++ b/crates/ide/src/diagnostics.rs @@ -136,6 +136,9 @@ pub(crate) fn diagnostics( .on::(|d| { res.borrow_mut().push(warning_with_fix(d, &sema)); }) + .on::(|d| { + res.borrow_mut().push(warning_with_fix(d, &sema)); + }) .on::(|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 579d5a30889a..cbfc66ab3c0f 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) -> Option { + 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, usage_file_id: FileId,