From f90010410e4f10f2f4d684fe58dbb2bc5a6f4785 Mon Sep 17 00:00:00 2001 From: Michael Goulet Date: Thu, 19 Jan 2023 21:13:01 +0000 Subject: [PATCH] Suggest fn call on pattern type mismatch --- compiler/rustc_hir_typeck/src/_match.rs | 2 +- compiler/rustc_hir_typeck/src/check.rs | 2 +- .../rustc_hir_typeck/src/fn_ctxt/checks.rs | 6 ++-- compiler/rustc_hir_typeck/src/pat.rs | 19 ++++++++--- .../suggest-call-on-pat-mismatch.rs | 16 +++++++++ .../suggest-call-on-pat-mismatch.stderr | 33 +++++++++++++++++++ 6 files changed, 68 insertions(+), 10 deletions(-) create mode 100644 tests/ui/suggestions/suggest-call-on-pat-mismatch.rs create mode 100644 tests/ui/suggestions/suggest-call-on-pat-mismatch.stderr diff --git a/compiler/rustc_hir_typeck/src/_match.rs b/compiler/rustc_hir_typeck/src/_match.rs index b6f19d3cc684a..c08c647797be9 100644 --- a/compiler/rustc_hir_typeck/src/_match.rs +++ b/compiler/rustc_hir_typeck/src/_match.rs @@ -41,7 +41,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { // #55810: Type check patterns first so we get types for all bindings. let scrut_span = scrut.span.find_ancestor_inside(expr.span).unwrap_or(scrut.span); for arm in arms { - self.check_pat_top(&arm.pat, scrutinee_ty, Some(scrut_span), true); + self.check_pat_top(&arm.pat, scrutinee_ty, Some(scrut_span), Some(scrut)); } // Now typecheck the blocks. diff --git a/compiler/rustc_hir_typeck/src/check.rs b/compiler/rustc_hir_typeck/src/check.rs index 57feefbcab6c8..549a6d7226588 100644 --- a/compiler/rustc_hir_typeck/src/check.rs +++ b/compiler/rustc_hir_typeck/src/check.rs @@ -90,7 +90,7 @@ pub(super) fn check_fn<'a, 'tcx>( for (idx, (param_ty, param)) in inputs_fn.chain(maybe_va_list).zip(body.params).enumerate() { // Check the pattern. let ty_span = try { inputs_hir?.get(idx)?.span }; - fcx.check_pat_top(¶m.pat, param_ty, ty_span, false); + fcx.check_pat_top(¶m.pat, param_ty, ty_span, None); // Check that argument is Sized. // The check for a non-trivial pattern is a hack to avoid duplicate warnings diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs index c9609e6943981..27157498e99ef 100644 --- a/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs +++ b/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs @@ -1325,11 +1325,11 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { // Does the expected pattern type originate from an expression and what is the span? let (origin_expr, ty_span) = match (decl.ty, decl.init) { - (Some(ty), _) => (false, Some(ty.span)), // Bias towards the explicit user type. + (Some(ty), _) => (None, Some(ty.span)), // Bias towards the explicit user type. (_, Some(init)) => { - (true, Some(init.span.find_ancestor_inside(decl.span).unwrap_or(init.span))) + (Some(init), Some(init.span.find_ancestor_inside(decl.span).unwrap_or(init.span))) } // No explicit type; so use the scrutinee. - _ => (false, None), // We have `let $pat;`, so the expected type is unconstrained. + _ => (None, None), // We have `let $pat;`, so the expected type is unconstrained. }; // Type check the pattern. Override if necessary to avoid knock-on errors. diff --git a/compiler/rustc_hir_typeck/src/pat.rs b/compiler/rustc_hir_typeck/src/pat.rs index 46799245222dc..52236ae56eeaa 100644 --- a/compiler/rustc_hir_typeck/src/pat.rs +++ b/compiler/rustc_hir_typeck/src/pat.rs @@ -46,7 +46,7 @@ struct TopInfo<'tcx> { /// Was the origin of the `span` from a scrutinee expression? /// /// Otherwise there is no scrutinee and it could be e.g. from the type of a formal parameter. - origin_expr: bool, + origin_expr: Option<&'tcx hir::Expr<'tcx>>, /// The span giving rise to the `expected` type, if one could be provided. /// /// If `origin_expr` is `true`, then this is the span of the scrutinee as in: @@ -74,7 +74,8 @@ struct TopInfo<'tcx> { impl<'tcx> FnCtxt<'_, 'tcx> { fn pattern_cause(&self, ti: TopInfo<'tcx>, cause_span: Span) -> ObligationCause<'tcx> { - let code = Pattern { span: ti.span, root_ty: ti.expected, origin_expr: ti.origin_expr }; + let code = + Pattern { span: ti.span, root_ty: ti.expected, origin_expr: ti.origin_expr.is_some() }; self.cause(cause_span, code) } @@ -85,7 +86,14 @@ impl<'tcx> FnCtxt<'_, 'tcx> { actual: Ty<'tcx>, ti: TopInfo<'tcx>, ) -> Option> { - self.demand_eqtype_with_origin(&self.pattern_cause(ti, cause_span), expected, actual) + let mut diag = + self.demand_eqtype_with_origin(&self.pattern_cause(ti, cause_span), expected, actual)?; + if let Some(expr) = ti.origin_expr { + self.suggest_fn_call(&mut diag, expr, expected, |output| { + self.can_eq(self.param_env, output, actual).is_ok() + }); + } + Some(diag) } fn demand_eqtype_pat( @@ -127,7 +135,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { pat: &'tcx Pat<'tcx>, expected: Ty<'tcx>, span: Option, - origin_expr: bool, + origin_expr: Option<&'tcx hir::Expr<'tcx>>, ) { let info = TopInfo { expected, origin_expr, span }; self.check_pat(pat, expected, INITIAL_BM, info); @@ -2146,7 +2154,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { err.help("the semantics of slice patterns changed recently; see issue #62254"); } else if self.autoderef(span, expected_ty) .any(|(ty, _)| matches!(ty.kind(), ty::Slice(..) | ty::Array(..))) - && let (Some(span), true) = (ti.span, ti.origin_expr) + && let Some(span) = ti.span + && let Some(_) = ti.origin_expr && let Ok(snippet) = self.tcx.sess.source_map().span_to_snippet(span) { let ty = self.resolve_vars_if_possible(ti.expected); diff --git a/tests/ui/suggestions/suggest-call-on-pat-mismatch.rs b/tests/ui/suggestions/suggest-call-on-pat-mismatch.rs new file mode 100644 index 0000000000000..657dd9c22c21b --- /dev/null +++ b/tests/ui/suggestions/suggest-call-on-pat-mismatch.rs @@ -0,0 +1,16 @@ +enum E { + One(i32, i32), +} + +fn main() { + let var = E::One; + if let E::One(var1, var2) = var { + //~^ ERROR mismatched types + //~| HELP use parentheses to construct this tuple variant + println!("{var1} {var2}"); + } + + let Some(x) = Some; + //~^ ERROR mismatched types + //~| HELP use parentheses to construct this tuple variant +} diff --git a/tests/ui/suggestions/suggest-call-on-pat-mismatch.stderr b/tests/ui/suggestions/suggest-call-on-pat-mismatch.stderr new file mode 100644 index 0000000000000..99d37f4672184 --- /dev/null +++ b/tests/ui/suggestions/suggest-call-on-pat-mismatch.stderr @@ -0,0 +1,33 @@ +error[E0308]: mismatched types + --> $DIR/suggest-call-on-pat-mismatch.rs:7:12 + | +LL | if let E::One(var1, var2) = var { + | ^^^^^^^^^^^^^^^^^^ --- this expression has type `fn(i32, i32) -> E {E::One}` + | | + | expected enum constructor, found enum `E` + | + = note: expected enum constructor `fn(i32, i32) -> E {E::One}` + found enum `E` +help: use parentheses to construct this tuple variant + | +LL | if let E::One(var1, var2) = var(/* i32 */, /* i32 */) { + | ++++++++++++++++++++++ + +error[E0308]: mismatched types + --> $DIR/suggest-call-on-pat-mismatch.rs:13:9 + | +LL | let Some(x) = Some; + | ^^^^^^^ ---- this expression has type `fn(_) -> Option<_> {Option::<_>::Some}` + | | + | expected enum constructor, found enum `Option` + | + = note: expected enum constructor `fn(_) -> Option<_> {Option::<_>::Some}` + found enum `Option<_>` +help: use parentheses to construct this tuple variant + | +LL | let Some(x) = Some(/* value */); + | +++++++++++++ + +error: aborting due to 2 previous errors + +For more information about this error, try `rustc --explain E0308`.