From af45d8a5bb4909e6908c4d7bba80eedcdcd7f961 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Esteban=20K=C3=BCber?= Date: Sat, 13 Jun 2020 12:08:32 -0700 Subject: [PATCH] Suggest new type param on single char ident Suggest new type parameter on single char uppercase ident even if it doesn't appear in a field's type parameter. Address comment in #72641. --- src/librustc_resolve/late/diagnostics.rs | 41 +++++++++++++++---- .../associated-types-eq-1.stderr | 11 ++++- .../type-not-found-in-adt-field.rs | 8 +++- .../type-not-found-in-adt-field.stderr | 16 ++++++-- 4 files changed, 61 insertions(+), 15 deletions(-) diff --git a/src/librustc_resolve/late/diagnostics.rs b/src/librustc_resolve/late/diagnostics.rs index 28ff89f66925e..694e2ac2a36a9 100644 --- a/src/librustc_resolve/late/diagnostics.rs +++ b/src/librustc_resolve/late/diagnostics.rs @@ -919,20 +919,45 @@ impl<'a> LateResolutionVisitor<'a, '_, '_> { &self, path: &[Segment], ) -> Option<(Span, &'static str, String, Applicability)> { - let ident = match path { - [segment] if !segment.has_args => segment.ident, + let (ident, span) = match path { + [segment] if !segment.has_args => (segment.ident.to_string(), segment.ident.span), _ => return None, }; - match ( - self.diagnostic_metadata.current_item, - self.diagnostic_metadata.currently_processing_generics, - ) { - (Some(Item { kind: ItemKind::Fn(..), ident, .. }), true) if ident.name == sym::main => { + let mut iter = ident.chars().map(|c| c.is_uppercase()); + let single_uppercase_char = + matches!(iter.next(), Some(true)) && matches!(iter.next(), None); + if !self.diagnostic_metadata.currently_processing_generics && !single_uppercase_char { + return None; + } + match (self.diagnostic_metadata.current_item, single_uppercase_char) { + (Some(Item { kind: ItemKind::Fn(..), ident, .. }), _) if ident.name == sym::main => { // Ignore `fn main()` as we don't want to suggest `fn main()` } - (Some(Item { kind, .. }), true) => { + ( + Some(Item { + kind: + kind @ ItemKind::Fn(..) + | kind @ ItemKind::Enum(..) + | kind @ ItemKind::Struct(..) + | kind @ ItemKind::Union(..), + .. + }), + true, + ) + | (Some(Item { kind, .. }), false) => { // Likely missing type parameter. if let Some(generics) = kind.generics() { + if span.overlaps(generics.span) { + // Avoid the following: + // error[E0405]: cannot find trait `A` in this scope + // --> $DIR/typo-suggestion-named-underscore.rs:CC:LL + // | + // L | fn foo(x: T) {} // Shouldn't suggest underscore + // | ^- help: you might be missing a type parameter: `, A` + // | | + // | not found in this scope + return None; + } let msg = "you might be missing a type parameter"; let (span, sugg) = if let [.., param] = &generics.params[..] { let span = if let [.., bound] = ¶m.bounds[..] { diff --git a/src/test/ui/associated-types/associated-types-eq-1.stderr b/src/test/ui/associated-types/associated-types-eq-1.stderr index 66c5f34644c01..53a45cf4e4f4d 100644 --- a/src/test/ui/associated-types/associated-types-eq-1.stderr +++ b/src/test/ui/associated-types/associated-types-eq-1.stderr @@ -4,7 +4,16 @@ error[E0412]: cannot find type `A` in this scope LL | fn foo2(x: I) { | - similarly named type parameter `I` defined here LL | let _: A = x.boo(); - | ^ help: a type parameter with a similar name exists: `I` + | ^ + | +help: a type parameter with a similar name exists + | +LL | let _: I = x.boo(); + | ^ +help: you might be missing a type parameter + | +LL | fn foo2(x: I) { + | ^^^ error: aborting due to previous error diff --git a/src/test/ui/suggestions/type-not-found-in-adt-field.rs b/src/test/ui/suggestions/type-not-found-in-adt-field.rs index 6bd42472f5a55..4cbfe58d35703 100644 --- a/src/test/ui/suggestions/type-not-found-in-adt-field.rs +++ b/src/test/ui/suggestions/type-not-found-in-adt-field.rs @@ -1,5 +1,9 @@ -struct S { - m: Vec>, //~ ERROR cannot find type `Hashmap` in this scope +struct Struct { + m: Vec>, //~ ERROR cannot find type `Someunknownname` in this scope + //~^ NOTE not found in this scope +} +struct OtherStruct { //~ HELP you might be missing a type parameter + m: K, //~ ERROR cannot find type `K` in this scope //~^ NOTE not found in this scope } fn main() {} diff --git a/src/test/ui/suggestions/type-not-found-in-adt-field.stderr b/src/test/ui/suggestions/type-not-found-in-adt-field.stderr index cfad8c689d038..e990fb5ba1210 100644 --- a/src/test/ui/suggestions/type-not-found-in-adt-field.stderr +++ b/src/test/ui/suggestions/type-not-found-in-adt-field.stderr @@ -1,9 +1,17 @@ -error[E0412]: cannot find type `Hashmap` in this scope +error[E0412]: cannot find type `Someunknownname` in this scope --> $DIR/type-not-found-in-adt-field.rs:2:12 | -LL | m: Vec>, - | ^^^^^^^ not found in this scope +LL | m: Vec>, + | ^^^^^^^^^^^^^^^ not found in this scope -error: aborting due to previous error +error[E0412]: cannot find type `K` in this scope + --> $DIR/type-not-found-in-adt-field.rs:6:8 + | +LL | struct OtherStruct { + | - help: you might be missing a type parameter: `` +LL | m: K, + | ^ not found in this scope + +error: aborting due to 2 previous errors For more information about this error, try `rustc --explain E0412`.