diff --git a/compiler/rustc_typeck/src/check/check.rs b/compiler/rustc_typeck/src/check/check.rs index 9c1fd9b30b460..c5fa8a5db0312 100644 --- a/compiler/rustc_typeck/src/check/check.rs +++ b/compiler/rustc_typeck/src/check/check.rs @@ -32,7 +32,6 @@ use rustc_trait_selection::traits::error_reporting::InferCtxtExt as _; use rustc_trait_selection::traits::{self, ObligationCtxt}; use rustc_ty_utils::representability::{self, Representability}; -use std::iter; use std::ops::ControlFlow; pub(super) fn check_abi(tcx: TyCtxt<'_>, hir_id: hir::HirId, span: Span, abi: Abi) { @@ -1494,76 +1493,109 @@ fn check_enum<'tcx>(tcx: TyCtxt<'tcx>, vs: &'tcx [hir::Variant<'tcx>], def_id: L } } - let mut disr_vals: Vec> = Vec::with_capacity(vs.len()); - // This tracks the previous variant span (in the loop) incase we need it for diagnostics - let mut prev_variant_span: Span = DUMMY_SP; - for ((_, discr), v) in iter::zip(def.discriminants(tcx), vs) { - // Check for duplicate discriminant values - if let Some(i) = disr_vals.iter().position(|&x| x.val == discr.val) { - let variant_did = def.variant(VariantIdx::new(i)).def_id; - let variant_i_hir_id = tcx.hir().local_def_id_to_hir_id(variant_did.expect_local()); - let variant_i = tcx.hir().expect_variant(variant_i_hir_id); - let i_span = match variant_i.disr_expr { - Some(ref expr) => tcx.hir().span(expr.hir_id), - None => tcx.def_span(variant_did), - }; - let span = match v.disr_expr { - Some(ref expr) => tcx.hir().span(expr.hir_id), - None => v.span, - }; - let display_discr = format_discriminant_overflow(tcx, v, discr); - let display_discr_i = format_discriminant_overflow(tcx, variant_i, disr_vals[i]); - let no_disr = v.disr_expr.is_none(); - let mut err = struct_span_err!( - tcx.sess, - sp, - E0081, - "discriminant value `{}` assigned more than once", - discr, - ); - - err.span_label(i_span, format!("first assignment of {display_discr_i}")); - err.span_label(span, format!("second assignment of {display_discr}")); - - if no_disr { - err.span_label( - prev_variant_span, - format!( - "assigned discriminant for `{}` was incremented from this discriminant", - v.ident - ), - ); - } - err.emit(); - } - - disr_vals.push(discr); - prev_variant_span = v.span; - } + detect_discriminant_duplicate(tcx, def.discriminants(tcx).collect(), vs, sp); check_representable(tcx, sp, def_id); check_transparent(tcx, sp, def); } -/// In the case that a discriminant is both a duplicate and an overflowing literal, -/// we insert both the assigned discriminant and the literal it overflowed from into the formatted -/// output. Otherwise we format the discriminant normally. -fn format_discriminant_overflow<'tcx>( +/// Part of enum check. Given the discriminants of an enum, errors if two or more discriminants are equal +fn detect_discriminant_duplicate<'tcx>( tcx: TyCtxt<'tcx>, - variant: &hir::Variant<'_>, - dis: Discr<'tcx>, -) -> String { - if let Some(expr) = &variant.disr_expr { - let body = &tcx.hir().body(expr.body).value; - if let hir::ExprKind::Lit(lit) = &body.kind - && let rustc_ast::LitKind::Int(lit_value, _int_kind) = &lit.node - && dis.val != *lit_value - { - return format!("`{dis}` (overflowed from `{lit_value}`)"); + mut discrs: Vec<(VariantIdx, Discr<'tcx>)>, + vs: &'tcx [hir::Variant<'tcx>], + self_span: Span, +) { + // Helper closure to reduce duplicate code. This gets called everytime we detect a duplicate. + // Here `idx` refers to the order of which the discriminant appears, and its index in `vs` + let report = |dis: Discr<'tcx>, + idx: usize, + err: &mut DiagnosticBuilder<'_, ErrorGuaranteed>| { + let var = &vs[idx]; // HIR for the duplicate discriminant + let (span, display_discr) = match var.disr_expr { + Some(ref expr) => { + // In the case the discriminant is both a duplicate and overflowed, let the user know + if let hir::ExprKind::Lit(lit) = &tcx.hir().body(expr.body).value.kind + && let rustc_ast::LitKind::Int(lit_value, _int_kind) = &lit.node + && *lit_value != dis.val + { + (tcx.hir().span(expr.hir_id), format!("`{dis}` (overflowed from `{lit_value}`)")) + // Otherwise, format the value as-is + } else { + (tcx.hir().span(expr.hir_id), format!("`{dis}`")) + } + } + None => { + // At this point we know this discriminant is a duplicate, and was not explicitly + // assigned by the user. Here we iterate backwards to fetch the HIR for the last + // explictly assigned discriminant, and letting the user know that this was the + // increment startpoint, and how many steps from there leading to the duplicate + if let Some((n, hir::Variant { span, ident, .. })) = + vs[..idx].iter().rev().enumerate().find(|v| v.1.disr_expr.is_some()) + { + let ve_ident = var.ident; + let n = n + 1; + let sp = if n > 1 { "variants" } else { "variant" }; + + err.span_label( + *span, + format!("discriminant for `{ve_ident}` incremented from this startpoint (`{ident}` + {n} {sp} later => `{ve_ident}` = {dis})"), + ); + } + + (vs[idx].span, format!("`{dis}`")) + } + }; + + err.span_label(span, format!("{display_discr} assigned here")); + }; + + // Here we loop through the discriminants, comparing each discriminant to another. + // When a duplicate is detected, we instatiate an error and point to both + // initial and duplicate value. The duplicate discriminant is then discarded by swapping + // it with the last element and decrementing the `vec.len` (which is why we have to evaluate + // `discrs.len()` anew every iteration, and why this could be tricky to do in a functional + // style as we are mutating `discrs` on the fly). + let mut i = 0; + while i < discrs.len() { + let hir_var_i_idx = discrs[i].0.index(); + let mut error: Option> = None; + + let mut o = i + 1; + while o < discrs.len() { + let hir_var_o_idx = discrs[o].0.index(); + + if discrs[i].1.val == discrs[o].1.val { + let err = error.get_or_insert_with(|| { + let mut ret = struct_span_err!( + tcx.sess, + self_span, + E0081, + "discriminant value `{}` assigned more than once", + discrs[i].1, + ); + + report(discrs[i].1, hir_var_i_idx, &mut ret); + + ret + }); + + report(discrs[o].1, hir_var_o_idx, err); + + // Safe to unwrap here, as we wouldn't reach this point if `discrs` was empty + discrs[o] = *discrs.last().unwrap(); + discrs.pop(); + } else { + o += 1; + } } - } - format!("`{dis}`") + if let Some(mut e) = error { + e.emit(); + } + + i += 1; + } } pub(super) fn check_type_params_are_used<'tcx>( diff --git a/compiler/rustc_typeck/src/check/mod.rs b/compiler/rustc_typeck/src/check/mod.rs index 17c2e4868aac7..199277abbc484 100644 --- a/compiler/rustc_typeck/src/check/mod.rs +++ b/compiler/rustc_typeck/src/check/mod.rs @@ -112,7 +112,6 @@ use rustc_hir::def_id::{DefId, LocalDefId}; use rustc_hir::intravisit::Visitor; use rustc_hir::{HirIdMap, ImplicitSelfKind, Node}; use rustc_index::bit_set::BitSet; -use rustc_index::vec::Idx; use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind}; use rustc_middle::ty::query::Providers; use rustc_middle::ty::subst::{InternalSubsts, Subst, SubstsRef}; diff --git a/src/test/ui/enum/enum-discrim-autosizing.rs b/src/test/ui/enum/enum-discrim-autosizing.rs index 27fab1bb505b2..fc94d281c77e2 100644 --- a/src/test/ui/enum/enum-discrim-autosizing.rs +++ b/src/test/ui/enum/enum-discrim-autosizing.rs @@ -6,9 +6,9 @@ enum Eu64 { //~^ ERROR discriminant value `0` assigned more than once Au64 = 0, - //~^NOTE first assignment of `0` + //~^NOTE `0` assigned here Bu64 = 0x8000_0000_0000_0000 - //~^NOTE second assignment of `0` (overflowed from `9223372036854775808`) + //~^NOTE `0` (overflowed from `9223372036854775808`) assigned here } fn main() {} diff --git a/src/test/ui/enum/enum-discrim-autosizing.stderr b/src/test/ui/enum/enum-discrim-autosizing.stderr index eacea86d67e55..be3d7c64e28bd 100644 --- a/src/test/ui/enum/enum-discrim-autosizing.stderr +++ b/src/test/ui/enum/enum-discrim-autosizing.stderr @@ -5,10 +5,10 @@ LL | enum Eu64 { | ^^^^^^^^^ LL | LL | Au64 = 0, - | - first assignment of `0` + | - `0` assigned here LL | LL | Bu64 = 0x8000_0000_0000_0000 - | --------------------- second assignment of `0` (overflowed from `9223372036854775808`) + | --------------------- `0` (overflowed from `9223372036854775808`) assigned here error: aborting due to previous error diff --git a/src/test/ui/error-codes/E0081.rs b/src/test/ui/error-codes/E0081.rs index 5aa6a786339cf..f53fda864d655 100644 --- a/src/test/ui/error-codes/E0081.rs +++ b/src/test/ui/error-codes/E0081.rs @@ -1,9 +1,9 @@ enum Enum { //~^ ERROR discriminant value `3` assigned more than once P = 3, - //~^ NOTE first assignment of `3` + //~^ NOTE `3` assigned here X = 3, - //~^ NOTE second assignment of `3` + //~^ NOTE `3` assigned here Y = 5 } @@ -11,20 +11,43 @@ enum Enum { enum EnumOverflowRepr { //~^ ERROR discriminant value `1` assigned more than once P = 257, - //~^ NOTE first assignment of `1` (overflowed from `257`) + //~^ NOTE `1` (overflowed from `257`) assigned here X = 513, - //~^ NOTE second assignment of `1` (overflowed from `513`) + //~^ NOTE `1` (overflowed from `513`) assigned here } #[repr(i8)] enum NegDisEnum { //~^ ERROR discriminant value `-1` assigned more than once First = -1, - //~^ NOTE first assignment of `-1` + //~^ NOTE `-1` assigned here Second = -2, - //~^ NOTE assigned discriminant for `Last` was incremented from this discriminant + //~^ NOTE discriminant for `Last` incremented from this startpoint (`Second` + 1 variant later => `Last` = -1) Last, - //~^ NOTE second assignment of `-1` + //~^ NOTE `-1` assigned here +} + +enum MultipleDuplicates { + //~^ ERROR discriminant value `0` assigned more than once + //~^^ ERROR discriminant value `-2` assigned more than once + V0, + //~^ NOTE `0` assigned here + V1 = 0, + //~^ NOTE `0` assigned here + V2, + V3, + V4 = 0, + //~^ NOTE `0` assigned here + V5 = -2, + //~^ NOTE discriminant for `V7` incremented from this startpoint (`V5` + 2 variants later => `V7` = 0) + //~^^ NOTE `-2` assigned here + V6, + V7, + //~^ NOTE `0` assigned here + V8 = -3, + //~^ NOTE discriminant for `V9` incremented from this startpoint (`V8` + 1 variant later => `V9` = -2) + V9, + //~^ NOTE `-2` assigned here } fn main() { diff --git a/src/test/ui/error-codes/E0081.stderr b/src/test/ui/error-codes/E0081.stderr index ff6113646bb8a..64562fefc866c 100644 --- a/src/test/ui/error-codes/E0081.stderr +++ b/src/test/ui/error-codes/E0081.stderr @@ -5,10 +5,10 @@ LL | enum Enum { | ^^^^^^^^^ LL | LL | P = 3, - | - first assignment of `3` + | - `3` assigned here LL | LL | X = 3, - | - second assignment of `3` + | - `3` assigned here error[E0081]: discriminant value `1` assigned more than once --> $DIR/E0081.rs:11:1 @@ -17,10 +17,10 @@ LL | enum EnumOverflowRepr { | ^^^^^^^^^^^^^^^^^^^^^ LL | LL | P = 257, - | --- first assignment of `1` (overflowed from `257`) + | --- `1` (overflowed from `257`) assigned here LL | LL | X = 513, - | --- second assignment of `1` (overflowed from `513`) + | --- `1` (overflowed from `513`) assigned here error[E0081]: discriminant value `-1` assigned more than once --> $DIR/E0081.rs:20:1 @@ -29,14 +29,50 @@ LL | enum NegDisEnum { | ^^^^^^^^^^^^^^^ LL | LL | First = -1, - | -- first assignment of `-1` + | -- `-1` assigned here LL | LL | Second = -2, - | ----------- assigned discriminant for `Last` was incremented from this discriminant + | ----------- discriminant for `Last` incremented from this startpoint (`Second` + 1 variant later => `Last` = -1) LL | LL | Last, - | ---- second assignment of `-1` + | ---- `-1` assigned here -error: aborting due to 3 previous errors +error[E0081]: discriminant value `0` assigned more than once + --> $DIR/E0081.rs:30:1 + | +LL | enum MultipleDuplicates { + | ^^^^^^^^^^^^^^^^^^^^^^^ +... +LL | V0, + | -- `0` assigned here +LL | +LL | V1 = 0, + | - `0` assigned here +... +LL | V4 = 0, + | - `0` assigned here +LL | +LL | V5 = -2, + | ------- discriminant for `V7` incremented from this startpoint (`V5` + 2 variants later => `V7` = 0) +... +LL | V7, + | -- `0` assigned here + +error[E0081]: discriminant value `-2` assigned more than once + --> $DIR/E0081.rs:30:1 + | +LL | enum MultipleDuplicates { + | ^^^^^^^^^^^^^^^^^^^^^^^ +... +LL | V5 = -2, + | -- `-2` assigned here +... +LL | V8 = -3, + | ------- discriminant for `V9` incremented from this startpoint (`V8` + 1 variant later => `V9` = -2) +LL | +LL | V9, + | -- `-2` assigned here + +error: aborting due to 5 previous errors For more information about this error, try `rustc --explain E0081`. diff --git a/src/test/ui/issues/issue-15524.rs b/src/test/ui/issues/issue-15524.rs deleted file mode 100644 index 565db2d0fcab8..0000000000000 --- a/src/test/ui/issues/issue-15524.rs +++ /dev/null @@ -1,16 +0,0 @@ -const N: isize = 1; - -enum Foo { - //~^ ERROR discriminant value `1` assigned more than once - //~| ERROR discriminant value `1` assigned more than once - //~| ERROR discriminant value `1` assigned more than once - A = 1, - B = 1, - C = 0, - D, - - E = N, - -} - -fn main() {} diff --git a/src/test/ui/issues/issue-15524.stderr b/src/test/ui/issues/issue-15524.stderr deleted file mode 100644 index 1195e0a346ddf..0000000000000 --- a/src/test/ui/issues/issue-15524.stderr +++ /dev/null @@ -1,40 +0,0 @@ -error[E0081]: discriminant value `1` assigned more than once - --> $DIR/issue-15524.rs:3:1 - | -LL | enum Foo { - | ^^^^^^^^ -... -LL | A = 1, - | - first assignment of `1` -LL | B = 1, - | - second assignment of `1` - -error[E0081]: discriminant value `1` assigned more than once - --> $DIR/issue-15524.rs:3:1 - | -LL | enum Foo { - | ^^^^^^^^ -... -LL | A = 1, - | - first assignment of `1` -LL | B = 1, -LL | C = 0, - | ----- assigned discriminant for `D` was incremented from this discriminant -LL | D, - | - second assignment of `1` - -error[E0081]: discriminant value `1` assigned more than once - --> $DIR/issue-15524.rs:3:1 - | -LL | enum Foo { - | ^^^^^^^^ -... -LL | A = 1, - | - first assignment of `1` -... -LL | E = N, - | - second assignment of `1` - -error: aborting due to 3 previous errors - -For more information about this error, try `rustc --explain E0081`. diff --git a/src/test/ui/tag-variant-disr-dup.rs b/src/test/ui/tag-variant-disr-dup.rs deleted file mode 100644 index e497f993da280..0000000000000 --- a/src/test/ui/tag-variant-disr-dup.rs +++ /dev/null @@ -1,12 +0,0 @@ -// Black and White have the same discriminator value ... - -enum Color { - //~^ ERROR discriminant value `0` assigned more than once - Red = 0xff0000, - Green = 0x00ff00, - Blue = 0x0000ff, - Black = 0x000000, - White = 0x000000, -} - -fn main() { } diff --git a/src/test/ui/tag-variant-disr-dup.stderr b/src/test/ui/tag-variant-disr-dup.stderr deleted file mode 100644 index 6b1ba43d2ba6e..0000000000000 --- a/src/test/ui/tag-variant-disr-dup.stderr +++ /dev/null @@ -1,14 +0,0 @@ -error[E0081]: discriminant value `0` assigned more than once - --> $DIR/tag-variant-disr-dup.rs:3:1 - | -LL | enum Color { - | ^^^^^^^^^^ -... -LL | Black = 0x000000, - | -------- first assignment of `0` -LL | White = 0x000000, - | -------- second assignment of `0` - -error: aborting due to previous error - -For more information about this error, try `rustc --explain E0081`.