From 2aa5555ad3911536e2d0d363633f1a4cb67b1c49 Mon Sep 17 00:00:00 2001 From: yukang Date: Mon, 23 Jan 2023 00:42:20 +0800 Subject: [PATCH] Fix #106496, suggest remove deref for type mismatch --- compiler/rustc_hir_typeck/src/demand.rs | 16 +++++++ .../issue-88360.fixed | 20 +++++++++ .../generic-associated-types/issue-88360.rs | 2 + .../issue-88360.stderr | 12 +++--- .../ui/suggestions/suggest-remove-deref.fixed | 28 ++++++++++++ tests/ui/suggestions/suggest-remove-deref.rs | 28 ++++++++++++ .../suggestions/suggest-remove-deref.stderr | 43 +++++++++++++++++++ 7 files changed, 144 insertions(+), 5 deletions(-) create mode 100644 tests/ui/generic-associated-types/issue-88360.fixed create mode 100644 tests/ui/suggestions/suggest-remove-deref.fixed create mode 100644 tests/ui/suggestions/suggest-remove-deref.rs create mode 100644 tests/ui/suggestions/suggest-remove-deref.stderr diff --git a/compiler/rustc_hir_typeck/src/demand.rs b/compiler/rustc_hir_typeck/src/demand.rs index 665dc8b6a2f..bd1626dff79 100644 --- a/compiler/rustc_hir_typeck/src/demand.rs +++ b/compiler/rustc_hir_typeck/src/demand.rs @@ -1233,6 +1233,22 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { sugg_sp = receiver.span; } } + + if let hir::ExprKind::Unary(hir::UnOp::Deref, ref inner) = expr.kind + && let Some(1) = self.deref_steps(expected, checked_ty) { + // We have `*&T`, check if what was expected was `&T`. + // If so, we may want to suggest removing a `*`. + sugg_sp = sugg_sp.with_hi(inner.span.lo()); + return Some(( + sugg_sp, + "consider removing deref here".to_string(), + "".to_string(), + Applicability::MachineApplicable, + true, + false, + )); + } + if let Ok(src) = sm.span_to_snippet(sugg_sp) { let needs_parens = match expr.kind { // parenthesize if needed (Issue #46756) diff --git a/tests/ui/generic-associated-types/issue-88360.fixed b/tests/ui/generic-associated-types/issue-88360.fixed new file mode 100644 index 00000000000..3dea8bf7ac8 --- /dev/null +++ b/tests/ui/generic-associated-types/issue-88360.fixed @@ -0,0 +1,20 @@ +// run-rustfix + +trait GatTrait { + type Gat<'a> where Self: 'a; + + fn test(&self) -> Self::Gat<'_>; +} + +trait SuperTrait +where + Self: 'static, + for<'a> Self: GatTrait = &'a T>, +{ + fn copy(&self) -> Self::Gat<'_> where T: Copy { + self.test() + //~^ mismatched types + } +} + +fn main() {} diff --git a/tests/ui/generic-associated-types/issue-88360.rs b/tests/ui/generic-associated-types/issue-88360.rs index c02690618d0..4d4c7ea3180 100644 --- a/tests/ui/generic-associated-types/issue-88360.rs +++ b/tests/ui/generic-associated-types/issue-88360.rs @@ -1,3 +1,5 @@ +// run-rustfix + trait GatTrait { type Gat<'a> where Self: 'a; diff --git a/tests/ui/generic-associated-types/issue-88360.stderr b/tests/ui/generic-associated-types/issue-88360.stderr index cd3750344dd..520aeff1894 100644 --- a/tests/ui/generic-associated-types/issue-88360.stderr +++ b/tests/ui/generic-associated-types/issue-88360.stderr @@ -1,5 +1,5 @@ error[E0308]: mismatched types - --> $DIR/issue-88360.rs:13:9 + --> $DIR/issue-88360.rs:15:9 | LL | trait SuperTrait | - this type parameter @@ -7,13 +7,15 @@ LL | trait SuperTrait LL | fn copy(&self) -> Self::Gat<'_> where T: Copy { | ------------- expected `&T` because of return type LL | *self.test() - | ^^^^^^^^^^^^ - | | - | expected `&T`, found type parameter `T` - | help: consider borrowing here: `&*self.test()` + | ^^^^^^^^^^^^ expected `&T`, found type parameter `T` | = note: expected reference `&T` found type parameter `T` +help: consider removing deref here + | +LL - *self.test() +LL + self.test() + | error: aborting due to previous error diff --git a/tests/ui/suggestions/suggest-remove-deref.fixed b/tests/ui/suggestions/suggest-remove-deref.fixed new file mode 100644 index 00000000000..4dc12da03dd --- /dev/null +++ b/tests/ui/suggestions/suggest-remove-deref.fixed @@ -0,0 +1,28 @@ +// run-rustfix + +//issue #106496 + +struct S; + +trait X {} +impl X for S {} + +fn foo(_: &T) {} +fn test_foo() { + let hello = &S; + foo(hello); + //~^ ERROR mismatched types +} + +fn bar(_: &String) {} +fn test_bar() { + let v = String::from("hello"); + let s = &v; + bar(s); + //~^ ERROR mismatched types +} + +fn main() { + test_foo(); + test_bar(); +} diff --git a/tests/ui/suggestions/suggest-remove-deref.rs b/tests/ui/suggestions/suggest-remove-deref.rs new file mode 100644 index 00000000000..c2d385cbdc3 --- /dev/null +++ b/tests/ui/suggestions/suggest-remove-deref.rs @@ -0,0 +1,28 @@ +// run-rustfix + +//issue #106496 + +struct S; + +trait X {} +impl X for S {} + +fn foo(_: &T) {} +fn test_foo() { + let hello = &S; + foo(*hello); + //~^ ERROR mismatched types +} + +fn bar(_: &String) {} +fn test_bar() { + let v = String::from("hello"); + let s = &v; + bar(*s); + //~^ ERROR mismatched types +} + +fn main() { + test_foo(); + test_bar(); +} diff --git a/tests/ui/suggestions/suggest-remove-deref.stderr b/tests/ui/suggestions/suggest-remove-deref.stderr new file mode 100644 index 00000000000..f5d810e36f0 --- /dev/null +++ b/tests/ui/suggestions/suggest-remove-deref.stderr @@ -0,0 +1,43 @@ +error[E0308]: mismatched types + --> $DIR/suggest-remove-deref.rs:13:9 + | +LL | foo(*hello); + | --- ^^^^^^ expected reference, found struct `S` + | | + | arguments to this function are incorrect + | + = note: expected reference `&_` + found struct `S` +note: function defined here + --> $DIR/suggest-remove-deref.rs:10:4 + | +LL | fn foo(_: &T) {} + | ^^^ ----- +help: consider removing deref here + | +LL - foo(*hello); +LL + foo(hello); + | + +error[E0308]: mismatched types + --> $DIR/suggest-remove-deref.rs:21:9 + | +LL | bar(*s); + | --- ^^ expected `&String`, found struct `String` + | | + | arguments to this function are incorrect + | +note: function defined here + --> $DIR/suggest-remove-deref.rs:17:4 + | +LL | fn bar(_: &String) {} + | ^^^ ---------- +help: consider removing deref here + | +LL - bar(*s); +LL + bar(s); + | + +error: aborting due to 2 previous errors + +For more information about this error, try `rustc --explain E0308`.