fixup! Add invalid null pointer usage lint.

Author: boxdot

clippy_lints/src/ptr.rs

@@ -15,6 +15,7 @@ use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::ty;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::source_map::Span;
+use rustc_span::symbol::Symbol;
 use rustc_span::{sym, MultiSpan};
 use std::borrow::Cow;
 
@@ -189,53 +190,50 @@ impl<'tcx> LateLintPass<'tcx> for Ptr {
 }
 
 fn check_invalid_ptr_usage<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
-    // (fn_path, arg_idx, num_args) -
-    //   `arg_idx` is the `arg` position where null would cause U.B.
-    //   `num_args` is the numbers of arguments of the function
-    const INVALID_NULL_PTR_USAGE_TABLE: [(&[&str], usize, usize); 20] = [
-        (&paths::SLICE_FROM_RAW_PARTS, 0, 2),
-        (&paths::SLICE_FROM_RAW_PARTS_MUT, 0, 2),
-        (&paths::PTR_COPY, 0, 3),
-        (&paths::PTR_COPY, 1, 3),
-        (&paths::PTR_COPY_NONOVERLAPPING, 0, 3),
-        (&paths::PTR_COPY_NONOVERLAPPING, 1, 3),
-        (&paths::PTR_READ, 0, 1),
-        (&paths::PTR_READ_UNALIGNED, 0, 1),
-        (&paths::PTR_READ_VOLATILE, 0, 1),
-        (&paths::PTR_REPLACE, 0, 2),
-        (&paths::PTR_SLICE_FROM_RAW_PARTS, 0, 2),
-        (&paths::PTR_SLICE_FROM_RAW_PARTS_MUT, 0, 2),
-        (&paths::PTR_SWAP, 0, 2),
-        (&paths::PTR_SWAP, 1, 2),
-        (&paths::PTR_SWAP_NONOVERLAPPING, 0, 3),
-        (&paths::PTR_SWAP_NONOVERLAPPING, 1, 3),
-        (&paths::PTR_WRITE, 0, 2),
-        (&paths::PTR_WRITE_UNALIGNED, 0, 2),
-        (&paths::PTR_WRITE_VOLATILE, 0, 2),
-        (&paths::PTR_WRITE_BYTES, 0, 3),
+    // (fn_path, arg_indices) - `arg_indices` are the `arg` positions where null would cause U.B.
+    const INVALID_NULL_PTR_USAGE_TABLE: [(&[&str], &[usize]); 16] = [
+        (&paths::SLICE_FROM_RAW_PARTS, &[0]),
+        (&paths::SLICE_FROM_RAW_PARTS_MUT, &[0]),
+        (&paths::PTR_COPY, &[0, 1]),
+        (&paths::PTR_COPY_NONOVERLAPPING, &[0, 1]),
+        (&paths::PTR_READ, &[0]),
+        (&paths::PTR_READ_UNALIGNED, &[0]),
+        (&paths::PTR_READ_VOLATILE, &[0]),
+        (&paths::PTR_REPLACE, &[0]),
+        (&paths::PTR_SLICE_FROM_RAW_PARTS, &[0]),
+        (&paths::PTR_SLICE_FROM_RAW_PARTS_MUT, &[0]),
+        (&paths::PTR_SWAP, &[0, 1]),
+        (&paths::PTR_SWAP_NONOVERLAPPING, &[0, 1]),
+        (&paths::PTR_WRITE, &[0]),
+        (&paths::PTR_WRITE_UNALIGNED, &[0]),
+        (&paths::PTR_WRITE_VOLATILE, &[0]),
+        (&paths::PTR_WRITE_BYTES, &[0]),
     ];
 
-    for (fn_path, arg_idx, num_args) in &INVALID_NULL_PTR_USAGE_TABLE {
-        if_chain! {
-            if let ExprKind::Call(ref fun, ref args) = expr.kind;
-            if args.len() == *num_args;
-            if let ExprKind::Path(ref qpath) = fun.kind;
-            if let Some(arg) = args.get(*arg_idx);
-            if let Some(fun_def_id) = cx.qpath_res(qpath, fun.hir_id).opt_def_id();
-            if match_def_path(cx, fun_def_id, fn_path);
-            if is_null_path(cx, arg);
-            then {
-                span_lint_and_sugg(
-                    cx,
-                    INVALID_NULL_PTR_USAGE,
-                    arg.span,
-                    "pointer must be non-null",
-                    "change this to",
-                    "core::ptr::NonNull::dangling().as_ptr()".to_string(),
-                    Applicability::MachineApplicable,
-                );
-                return;
+    if_chain! {
+        if let ExprKind::Call(ref fun, ref args) = expr.kind;
+        if let ExprKind::Path(ref qpath) = fun.kind;
+        if let Some(fun_def_id) = cx.qpath_res(qpath, fun.hir_id).opt_def_id();
+        let fun_def_path = cx.get_def_path(fun_def_id).into_iter().map(Symbol::to_ident_string).collect::<Vec<_>>();
+        if let Some(arg) = INVALID_NULL_PTR_USAGE_TABLE.iter().find_map(|(fn_path, arg_indices)| {
+            if fn_path == &fun_def_path {
+                arg_indices.iter().find_map(|arg_idx| {
+                    args.get(*arg_idx).filter(|arg| is_null_path(cx, arg))
+                })
+            } else {
+                None
             }
+        });
+        then {
+            span_lint_and_sugg(
+                cx,
+                INVALID_NULL_PTR_USAGE,
+                arg.span,
+                "pointer must be non-null",
+                "change this to",
+                "core::ptr::NonNull::dangling().as_ptr()".to_string(),
+                Applicability::MachineApplicable,
+            );
         }
     }
 }
@@ -422,8 +420,7 @@ fn get_rptr_lm<'tcx>(ty: &'tcx Ty<'tcx>) -> Option<(&'tcx Lifetime, Mutability,
 
 fn is_null_path(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
     if_chain! {
-        if let ExprKind::Call(path, args) = expr.kind;
-        if args.is_empty();
+        if let ExprKind::Call(path, []) = expr.kind;
         if let ExprKind::Path(ref qpath) = path.kind;
         if let Some(fn_def_id) = cx.qpath_res(qpath, path.hir_id).opt_def_id();
         then {

clippy_utils/src/paths.rs

@@ -144,7 +144,6 @@ pub const STD_CONVERT_IDENTITY: [&str; 3] = ["std", "convert", "identity"];
 pub const STD_FS_CREATE_DIR: [&str; 3] = ["std", "fs", "create_dir"];
 pub const STD_MEM_TRANSMUTE: [&str; 3] = ["std", "mem", "transmute"];
 pub const STD_PTR_NULL: [&str; 3] = ["std", "ptr", "null"];
-pub const STD_PTR_NULL_MUT: [&str; 3] = ["std", "ptr", "null_mut"];
 pub const STRING_AS_MUT_STR: [&str; 4] = ["alloc", "string", "String", "as_mut_str"];
 pub const STRING_AS_STR: [&str; 4] = ["alloc", "string", "String", "as_str"];
 pub const STR_ENDS_WITH: [&str; 4] = ["core", "str", "<impl str>", "ends_with"];