Auto merge of rust-lang#7968 - Jarcho:manual_map_unsafe, r=xFrednet

Fix `manual_map` with unsafe functions

fixes: rust-lang#7820
changelog: Fix `manual_map` suggestion when used with unsafe functions and unsafe blocks

Author: bors

clippy_lints/src/manual_map.rs

@@ -2,7 +2,7 @@ use crate::{map_unit_fn::OPTION_MAP_UNIT_FN, matches::MATCH_AS_REF};
 use clippy_utils::diagnostics::span_lint_and_sugg;
 use clippy_utils::higher::IfLetOrMatch;
 use clippy_utils::source::{snippet_with_applicability, snippet_with_context};
-use clippy_utils::ty::{is_type_diagnostic_item, peel_mid_ty_refs_is_mutable};
+use clippy_utils::ty::{is_type_diagnostic_item, peel_mid_ty_refs_is_mutable, type_is_unsafe_function};
 use clippy_utils::{
     can_move_expr_to_closure, in_constant, is_else_clause, is_lang_ctor, is_lint_allowed, path_to_local_id,
     peel_hir_expr_refs, peel_hir_expr_while, CaptureKind,
@@ -11,7 +11,8 @@ use rustc_ast::util::parser::PREC_POSTFIX;
 use rustc_errors::Applicability;
 use rustc_hir::LangItem::{OptionNone, OptionSome};
 use rustc_hir::{
-    def::Res, Arm, BindingAnnotation, Block, Expr, ExprKind, HirId, Mutability, Pat, PatKind, Path, QPath,
+    def::Res, Arm, BindingAnnotation, Block, BlockCheckMode, Expr, ExprKind, HirId, Mutability, Pat, PatKind, Path,
+    QPath, UnsafeSource,
 };
 use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_middle::lint::in_external_macro;
@@ -93,20 +94,20 @@ impl LateLintPass<'_> for ManualMap {
             return;
         }
 
-        let some_expr = match get_some_expr(cx, some_expr, expr_ctxt) {
+        let some_expr = match get_some_expr(cx, some_expr, false, expr_ctxt) {
             Some(expr) => expr,
             None => return,
         };
 
         // These two lints will go back and forth with each other.
-        if cx.typeck_results().expr_ty(some_expr) == cx.tcx.types.unit
+        if cx.typeck_results().expr_ty(some_expr.expr) == cx.tcx.types.unit
             && !is_lint_allowed(cx, OPTION_MAP_UNIT_FN, expr.hir_id)
         {
             return;
         }
 
         // `map` won't perform any adjustments.
-        if !cx.typeck_results().expr_adjustments(some_expr).is_empty() {
+        if !cx.typeck_results().expr_adjustments(some_expr.expr).is_empty() {
             return;
         }
 
@@ -120,7 +121,7 @@ impl LateLintPass<'_> for ManualMap {
             None => "",
         };
 
-        match can_move_expr_to_closure(cx, some_expr) {
+        match can_move_expr_to_closure(cx, some_expr.expr) {
             Some(captures) => {
                 // Check if captures the closure will need conflict with borrows made in the scrutinee.
                 // TODO: check all the references made in the scrutinee expression. This will require interacting
@@ -158,12 +159,14 @@ impl LateLintPass<'_> for ManualMap {
             };
 
         let body_str = if let PatKind::Binding(annotation, id, some_binding, None) = some_pat.kind {
-            match can_pass_as_func(cx, id, some_expr) {
-                Some(func) if func.span.ctxt() == some_expr.span.ctxt() => {
+            if_chain! {
+                if !some_expr.needs_unsafe_block;
+                if let Some(func) = can_pass_as_func(cx, id, some_expr.expr);
+                if func.span.ctxt() == some_expr.expr.span.ctxt();
+                then {
                     snippet_with_applicability(cx, func.span, "..", &mut app).into_owned()
-                },
-                _ => {
-                    if path_to_local_id(some_expr, id)
+                } else {
+                    if path_to_local_id(some_expr.expr, id)
                         && !is_lint_allowed(cx, MATCH_AS_REF, expr.hir_id)
                         && binding_ref.is_some()
                     {
@@ -176,21 +179,23 @@ impl LateLintPass<'_> for ManualMap {
                     } else {
                         ""
                     };
-                    format!(
-                        "|{}{}| {}",
-                        annotation,
-                        some_binding,
-                        snippet_with_context(cx, some_expr.span, expr_ctxt, "..", &mut app).0
-                    )
-                },
+                    let expr_snip = snippet_with_context(cx, some_expr.expr.span, expr_ctxt, "..", &mut app).0;
+                    if some_expr.needs_unsafe_block {
+                        format!("|{}{}| unsafe {{ {} }}", annotation, some_binding, expr_snip)
+                    } else {
+                        format!("|{}{}| {}", annotation, some_binding, expr_snip)
+                    }
+                }
             }
         } else if !is_wild_none && explicit_ref.is_none() {
             // TODO: handle explicit reference annotations.
-            format!(
-                "|{}| {}",
-                snippet_with_context(cx, some_pat.span, expr_ctxt, "..", &mut app).0,
-                snippet_with_context(cx, some_expr.span, expr_ctxt, "..", &mut app).0
-            )
+            let pat_snip = snippet_with_context(cx, some_pat.span, expr_ctxt, "..", &mut app).0;
+            let expr_snip = snippet_with_context(cx, some_expr.expr.span, expr_ctxt, "..", &mut app).0;
+            if some_expr.needs_unsafe_block {
+                format!("|{}| unsafe {{ {} }}", pat_snip, expr_snip)
+            } else {
+                format!("|{}| {}", pat_snip, expr_snip)
+            }
         } else {
             // Refutable bindings and mixed reference annotations can't be handled by `map`.
             return;
@@ -217,7 +222,9 @@ impl LateLintPass<'_> for ManualMap {
 fn can_pass_as_func(cx: &LateContext<'tcx>, binding: HirId, expr: &'tcx Expr<'_>) -> Option<&'tcx Expr<'tcx>> {
     match expr.kind {
         ExprKind::Call(func, [arg])
-            if path_to_local_id(arg, binding) && cx.typeck_results().expr_adjustments(arg).is_empty() =>
+            if path_to_local_id(arg, binding)
+                && cx.typeck_results().expr_adjustments(arg).is_empty()
+                && !type_is_unsafe_function(cx, cx.typeck_results().expr_ty(func).peel_refs()) =>
         {
             Some(func)
         },
@@ -237,6 +244,11 @@ enum OptionPat<'a> {
     },
 }
 
+struct SomeExpr<'tcx> {
+    expr: &'tcx Expr<'tcx>,
+    needs_unsafe_block: bool,
+}
+
 // Try to parse into a recognized `Option` pattern.
 // i.e. `_`, `None`, `Some(..)`, or a reference to any of those.
 fn try_parse_pattern(cx: &LateContext<'tcx>, pat: &'tcx Pat<'_>, ctxt: SyntaxContext) -> Option<OptionPat<'tcx>> {
@@ -257,7 +269,12 @@ fn try_parse_pattern(cx: &LateContext<'tcx>, pat: &'tcx Pat<'_>, ctxt: SyntaxCon
 }
 
 // Checks for an expression wrapped by the `Some` constructor. Returns the contained expression.
-fn get_some_expr(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, ctxt: SyntaxContext) -> Option<&'tcx Expr<'tcx>> {
+fn get_some_expr(
+    cx: &LateContext<'tcx>,
+    expr: &'tcx Expr<'_>,
+    needs_unsafe_block: bool,
+    ctxt: SyntaxContext,
+) -> Option<SomeExpr<'tcx>> {
     // TODO: Allow more complex expressions.
     match expr.kind {
         ExprKind::Call(
@@ -266,15 +283,24 @@ fn get_some_expr(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, ctxt: SyntaxConte
                 ..
             },
             [arg],
-        ) if ctxt == expr.span.ctxt() && is_lang_ctor(cx, qpath, OptionSome) => Some(arg),
+        ) if ctxt == expr.span.ctxt() && is_lang_ctor(cx, qpath, OptionSome) => Some(SomeExpr {
+            expr: arg,
+            needs_unsafe_block,
+        }),
         ExprKind::Block(
             Block {
                 stmts: [],
                 expr: Some(expr),
+                rules,
                 ..
             },
             _,
-        ) => get_some_expr(cx, expr, ctxt),
+        ) => get_some_expr(
+            cx,
+            expr,
+            needs_unsafe_block || *rules == BlockCheckMode::UnsafeBlock(UnsafeSource::UserProvided),
+            ctxt,
+        ),
         _ => None,
     }
 }

tests/ui/manual_map_option_2.fixed

@@ -47,4 +47,14 @@ fn main() {
     let _ = s.as_ref().map(|x| {
             if let Some(ref s) = s { (x.clone(), s) } else { panic!() }
         });
+
+    // Issue #7820
+    unsafe fn f(x: u32) -> u32 {
+        x
+    }
+    unsafe {
+        let _ = Some(0).map(|x| f(x));
+    }
+    let _ = Some(0).map(|x| unsafe { f(x) });
+    let _ = Some(0).map(|x| unsafe { f(x) });
 }

tests/ui/manual_map_option_2.rs

@@ -53,4 +53,23 @@ fn main() {
         }),
         None => None,
     };
+
+    // Issue #7820
+    unsafe fn f(x: u32) -> u32 {
+        x
+    }
+    unsafe {
+        let _ = match Some(0) {
+            Some(x) => Some(f(x)),
+            None => None,
+        };
+    }
+    let _ = match Some(0) {
+        Some(x) => unsafe { Some(f(x)) },
+        None => None,
+    };
+    let _ = match Some(0) {
+        Some(x) => Some(unsafe { f(x) }),
+        None => None,
+    };
 }

tests/ui/manual_map_option_2.stderr

@@ -39,5 +39,35 @@ LL +             if let Some(ref s) = s { (x.clone(), s) } else { panic!() }
 LL ~         });
    |
 
-error: aborting due to 2 previous errors
+error: manual implementation of `Option::map`
+  --> $DIR/manual_map_option_2.rs:62:17
+   |
+LL |           let _ = match Some(0) {
+   |  _________________^
+LL | |             Some(x) => Some(f(x)),
+LL | |             None => None,
+LL | |         };
+   | |_________^ help: try this: `Some(0).map(|x| f(x))`
+
+error: manual implementation of `Option::map`
+  --> $DIR/manual_map_option_2.rs:67:13
+   |
+LL |       let _ = match Some(0) {
+   |  _____________^
+LL | |         Some(x) => unsafe { Some(f(x)) },
+LL | |         None => None,
+LL | |     };
+   | |_____^ help: try this: `Some(0).map(|x| unsafe { f(x) })`
+
+error: manual implementation of `Option::map`
+  --> $DIR/manual_map_option_2.rs:71:13
+   |
+LL |       let _ = match Some(0) {
+   |  _____________^
+LL | |         Some(x) => Some(unsafe { f(x) }),
+LL | |         None => None,
+LL | |     };
+   | |_____^ help: try this: `Some(0).map(|x| unsafe { f(x) })`
+
+error: aborting due to 5 previous errors