Move desugar_await to clippy_utils

Author: samueltardieu

clippy_lints/src/redundant_async_block.rs

@@ -1,14 +1,9 @@
-use std::ops::ControlFlow;
-
 use clippy_utils::diagnostics::span_lint_and_sugg;
-use clippy_utils::peel_blocks;
 use clippy_utils::source::{snippet, walk_span_to_context};
 use clippy_utils::ty::implements_trait;
-use clippy_utils::visitors::for_each_expr_without_closures;
+use clippy_utils::{desugar_await, peel_blocks};
 use rustc_errors::Applicability;
-use rustc_hir::{
-    Closure, ClosureKind, CoroutineDesugaring, CoroutineKind, CoroutineSource, Expr, ExprKind, MatchSource,
-};
+use rustc_hir::{Closure, ClosureKind, CoroutineDesugaring, CoroutineKind, CoroutineSource, Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::ty::UpvarCapture;
 use rustc_session::declare_lint_pass;
@@ -99,20 +94,3 @@ fn desugar_async_block<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> Op
         None
     }
 }
-
-/// If `expr` is a desugared `.await`, return the original expression if it does not come from a
-/// macro expansion.
-fn desugar_await<'tcx>(expr: &'tcx Expr<'_>) -> Option<&'tcx Expr<'tcx>> {
-    if let ExprKind::Match(match_value, _, MatchSource::AwaitDesugar) = expr.kind
-        && let ExprKind::Call(_, [into_future_arg]) = match_value.kind
-        && let ctxt = expr.span.ctxt()
-        && for_each_expr_without_closures(into_future_arg, |e| {
-            walk_span_to_context(e.span, ctxt).map_or(ControlFlow::Break(()), |_| ControlFlow::Continue(()))
-        })
-        .is_none()
-    {
-        Some(into_future_arg)
-    } else {
-        None
-    }
-}

clippy_utils/src/lib.rs

@@ -126,6 +126,7 @@ use rustc_span::hygiene::{ExpnKind, MacroKind};
 use rustc_span::source_map::SourceMap;
 use rustc_span::symbol::{Ident, Symbol, kw};
 use rustc_span::{InnerSpan, Span, sym};
+use source::walk_span_to_context;
 use visitors::{Visitable, for_each_unconsumed_temporary};
 
 use crate::consts::{ConstEvalCtxt, Constant, mir_to_const};
@@ -3718,3 +3719,20 @@ pub fn peel_hir_ty_options<'tcx>(cx: &LateContext<'tcx>, mut hir_ty: &'tcx hir::
     }
     hir_ty
 }
+
+/// If `expr` is a desugared `.await`, return the original expression if it does not come from a
+/// macro expansion.
+pub fn desugar_await<'tcx>(expr: &'tcx Expr<'_>) -> Option<&'tcx Expr<'tcx>> {
+    if let ExprKind::Match(match_value, _, MatchSource::AwaitDesugar) = expr.kind
+        && let ExprKind::Call(_, [into_future_arg]) = match_value.kind
+        && let ctxt = expr.span.ctxt()
+        && for_each_expr_without_closures(into_future_arg, |e| {
+            walk_span_to_context(e.span, ctxt).map_or(ControlFlow::Break(()), |_| ControlFlow::Continue(()))
+        })
+        .is_none()
+    {
+        Some(into_future_arg)
+    } else {
+        None
+    }
+}