From 1316422a7c2ef26e9da78fa23f170407b1cb39bb Mon Sep 17 00:00:00 2001 From: Phil Ellison Date: Mon, 28 Dec 2020 13:41:15 +0000 Subject: Add diagnostic for filter_map followed by next --- crates/hir_ty/src/diagnostics.rs | 48 ++++++++++++++++++++++-- crates/hir_ty/src/diagnostics/expr.rs | 70 ++++++++++++++++++++++++++++++----- 2 files changed, 105 insertions(+), 13 deletions(-) (limited to 'crates/hir_ty/src') diff --git a/crates/hir_ty/src/diagnostics.rs b/crates/hir_ty/src/diagnostics.rs index 247da43f2..b4cf81c10 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, + pub filter_map_expr: AstPtr, + 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.filter_map_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 +669,19 @@ fn foo() { break; } "#, ); } + + #[test] + fn replace_missing_filter_next_with_find_map() { + check_diagnostics( + 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(..) + } + "#, + ); + } } diff --git a/crates/hir_ty/src/diagnostics/expr.rs b/crates/hir_ty/src/diagnostics/expr.rs index 107417c27..170d23178 100644 --- a/crates/hir_ty/src/diagnostics/expr.rs +++ b/crates/hir_ty/src/diagnostics/expr.rs @@ -24,6 +24,8 @@ pub(crate) use hir_def::{ LocalFieldId, VariantId, }; +use super::ReplaceFilterMapNextWithFindMap; + pub(super) struct ExprValidator<'a, 'b: 'a> { owner: DefWithBodyId, infer: Arc, @@ -39,7 +41,18 @@ impl<'a, 'b> ExprValidator<'a, 'b> { ExprValidator { owner, infer, sink } } + fn bar() { + // LOOK FOR THIS + let m = [1, 2, 3] + .iter() + .filter_map(|x| if *x == 2 { Some(4) } else { None }) + .next(); + } + pub(super) fn validate_body(&mut self, db: &dyn HirDatabase) { + // DO NOT MERGE: just getting something working for now + self.check_for_filter_map_next(db); + let body = db.body(self.owner.into()); for (id, expr) in body.exprs.iter() { @@ -150,20 +163,58 @@ 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) { + let body = db.body(self.owner.into()); + let mut prev = None; + + for (id, expr) in body.exprs.iter() { + if let Expr::MethodCall { receiver, method_name, args, .. } = expr { + let method_name_hack_do_not_merge = format!("{}", method_name); + + if method_name_hack_do_not_merge == "filter_map" && args.len() == 1 { + prev = Some((id, args[0])); + continue; + } + + if method_name_hack_do_not_merge == "next" { + if let Some((filter_map_id, filter_map_args)) = prev { + if *receiver == filter_map_id { + let (_, source_map) = db.body_with_source_map(self.owner.into()); + if let (Ok(filter_map_source_ptr), Ok(next_source_ptr)) = ( + source_map.expr_syntax(filter_map_id), + source_map.expr_syntax(id), + ) { + self.sink.push(ReplaceFilterMapNextWithFindMap { + file: filter_map_source_ptr.file_id, + filter_map_expr: filter_map_source_ptr.value, + 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 +226,25 @@ 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 +267,6 @@ impl<'a, 'b> ExprValidator<'a, 'b> { }); } } - - None } fn validate_match( -- cgit v1.2.3