Suggest adding return if the type of unused semi return value can c… · rust-lang/rust@25d38c4 (original) (raw)
`@@ -11,7 +11,7 @@ use crate::{
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`use rustc_ast as ast;
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`use rustc_data_structures::fx::FxIndexSet;
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`use rustc_errors::{
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``
`-
pluralize, Applicability, Diagnostic, DiagnosticId, ErrorGuaranteed, MultiSpan,
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``
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`+
pluralize, Applicability, Diagnostic, DiagnosticId, ErrorGuaranteed, MultiSpan, StashKey,
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`};
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`use rustc_hir as hir;
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`use rustc_hir::def::{CtorOf, DefKind, Res};
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`@@ -27,6 +27,7 @@ use rustc_infer::infer::error_reporting::{FailureCode, ObligationCauseExt};
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`use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
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`use rustc_infer::infer::TypeTrace;
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`use rustc_infer::infer::{DefineOpaqueTypes, InferOk};
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``
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`+
use rustc_middle::traits::ObligationCauseCode::ExprBindingObligation;
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`use rustc_middle::ty::adjustment::AllowTwoPhase;
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`use rustc_middle::ty::visit::TypeVisitableExt;
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`use rustc_middle::ty::{self, IsSuggestable, Ty, TyCtxt};
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`@@ -1375,7 +1376,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
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`}
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` _ => bug!("unexpected type: {:?}", ty.normalized),
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`},
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``
`-
Res::Def(DefKind::Struct | DefKind::Union | DefKind::TyAlias | DefKind::AssocTy, _)
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Res::Def(
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DefKind::Struct | DefKind::Union | DefKind::TyAlias { .. } | DefKind::AssocTy,
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_,
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``
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)
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` | Res::SelfTyParam { .. }
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` | Res::SelfTyAlias { .. } => match ty.normalized.ty_adt_def() {
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`Some(adt) if !adt.is_enum() => {
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`@@ -1845,6 +1849,55 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
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`}
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`}
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``
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pub(super) fn collect_unused_stmts_for_coerce_return_ty(
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&self,
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errors_causecode: Vec<(Span, ObligationCauseCode<'tcx>)>,
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) {
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for (span, code) in errors_causecode {
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let Some(mut diag) =
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self.tcx.sess.diagnostic().steal_diagnostic(span, StashKey::MaybeForgetReturn)
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else {
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continue;
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};
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``
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if let Some(fn_sig) = self.body_fn_sig()
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&& let ExprBindingObligation(_, _, hir_id, ..) = code
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&& !fn_sig.output().is_unit()
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{
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let mut block_num = 0;
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let mut found_semi = false;
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for (_, node) in self.tcx.hir().parent_iter(hir_id) {
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match node {
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hir::Node::Stmt(stmt) => if let hir::StmtKind::Semi(ref expr) = stmt.kind {
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let expr_ty = self.typeck_results.borrow().expr_ty(expr);
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let return_ty = fn_sig.output();
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if !matches!(expr.kind, hir::ExprKind::Ret(..)) &&
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self.can_coerce(expr_ty, return_ty) {
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found_semi = true;
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}
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},
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hir::Node::Block(_block) => if found_semi {
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block_num += 1;
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}
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hir::Node::Item(item) => if let hir::ItemKind::Fn(..) = item.kind {
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break;
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}
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_ => {}
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}
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}
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if block_num > 1 && found_semi {
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diag.span_suggestion_verbose(
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span.shrink_to_lo(),
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"you might have meant to return this to infer its type parameters",
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"return ",
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Applicability::MaybeIncorrect,
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);
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}
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}
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diag.emit();
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}
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}
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`/// Given a vector of fulfillment errors, try to adjust the spans of the
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`/// errors to more accurately point at the cause of the failure.
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`///
`