add details

Author: Soveu

clippy_lints/src/pointer_in_nomem_asm_block.rs

@@ -35,9 +35,8 @@ fn yeet_lint(cx: &LateContext<'_>, asm: &InlineAsm<'_>, asm_span: Span, op_spans
 
     span_lint_and_then(cx, POINTER_IN_NOMEM_ASM_BLOCK, op_spans, "passing pointer to nomem asm block", |diag| {
         if let Some(probably_asm_options_span) = probably_asm_options_span {
-            diag.span_suggestion(probably_asm_options_span, "heeelppp", "suggg", Applicability::MaybeIncorrect);
+            diag.span_note(probably_asm_options_span, "flags declared here");
         }
-        // note_span.inspect(|s| { diag.span_note(*s, "declared here"); });
     });
 }
 
@@ -58,21 +57,28 @@ fn check_asm(cx: &LateContext<'_>, asm: &InlineAsm<'_>, asm_span: Span) {
 
 declare_clippy_lint! {
     /// ### What it does
+    /// Checks if any pointer is being passed to an asm! block with `nomem` option.
     ///
     /// ### Why is this bad?
+    /// `nomem` forbids any reads or writes to memory and passing a pointer suggests
+    /// that either of those will happen.
     ///
     /// ### Example
     /// ```no_run
-    /// // example code where clippy issues a warning
+    /// fn f(p: *mut u32) {
+    ///     unsafe { core::arch::asm!("mov [{p}], 42", p = in(reg) p, options(nomem, nostack)); }
+    /// }
     /// ```
     /// Use instead:
     /// ```no_run
-    /// // example code which does not raise clippy warning
+    /// fn f(p: *mut u32) {
+    ///     unsafe { core::arch::asm!("mov [{p}], 42", p = in(reg) p, options(nostack)); }
+    /// }
     /// ```
     #[clippy::version = "1.81.0"]
     pub POINTER_IN_NOMEM_ASM_BLOCK,
     suspicious,
-    "default lint description"
+    "pointer in nomem asm block"
 }
 
 declare_lint_pass!(PointerInNomemAsmBlock => [POINTER_IN_NOMEM_ASM_BLOCK]);

tests/ui/pointer_in_nomem_asm_block.stderr

@@ -0,0 +1,23 @@
+error: passing pointer to nomem asm block
+  --> tests/ui/pointer_in_nomem_asm_block.rs:8:9
+   |
+LL |           p1 = in(reg) p,
+   |           ^^^^^^^^^^^^^^
+LL |           p2 = in(reg) p as *const _ as usize,
+LL |           p3 = in(reg) p,
+   |           ^^^^^^^^^^^^^^
+LL | /         options(nomem, nostack, preserves_flags)
+LL | |     );
+   | |_____- help: remove `nomem`
+   |
+   = note: `-D clippy::pointer-in-nomem-asm-block` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::pointer_in_nomem_asm_block)]`
+
+error: passing pointer to nomem asm block
+  --> tests/ui/pointer_in_nomem_asm_block.rs:33:34
+   |
+LL |     core::arch::asm!("asdf {p}", p = in(reg) p, options(nomem, nostack, preserves_flags));
+   |                                  ^^^^^^^^^^^^^  ----------------------------------------- help: remove `nomem`
+
+error: aborting due to 2 previous errors
+