Address review comments

Author: Urgau

compiler/rustc_lint/src/lints.rs

@@ -1359,10 +1359,12 @@ pub(crate) enum NonUpperCaseGlobalSub {
         #[primary_span]
         span: Span,
     },
-    #[suggestion(lint_suggestion, code = "{replace}", applicability = "machine-applicable")]
+    #[suggestion(lint_suggestion, code = "{replace}")]
     Suggestion {
         #[primary_span]
         span: Span,
+        #[applicability]
+        applicability: Applicability,
         replace: String,
     },
 }

compiler/rustc_lint/src/nonstandard_style.rs

@@ -1,7 +1,9 @@
 use rustc_abi::ExternAbi;
 use rustc_attr_data_structures::{AttributeKind, ReprAttr};
 use rustc_attr_parsing::AttributeParser;
+use rustc_errors::Applicability;
 use rustc_hir::def::{DefKind, Res};
+use rustc_hir::def_id::DefId;
 use rustc_hir::intravisit::{FnKind, Visitor};
 use rustc_hir::{AttrArgs, AttrItem, Attribute, GenericParamKind, PatExprKind, PatKind};
 use rustc_middle::hir::nested_filter::All;
@@ -495,17 +497,33 @@ impl NonUpperCaseGlobals {
         if name.chars().any(|c| c.is_lowercase()) {
             let uc = NonSnakeCase::to_snake_case(name).to_uppercase();
 
+            // If the item is exported, suggesting changing it's name would be breaking-change
+            // and could break users without a "nice" applicable fix, so let's avoid it.
+            let can_change_usages = if let Some(did) = did {
+                !cx.tcx.effective_visibilities(()).is_exported(did)
+            } else {
+                false
+            };
+
             // We cannot provide meaningful suggestions
             // if the characters are in the category of "Lowercase Letter".
             let sub = if *name != uc {
-                NonUpperCaseGlobalSub::Suggestion { span: ident.span, replace: uc.clone() }
+                NonUpperCaseGlobalSub::Suggestion {
+                    span: ident.span,
+                    replace: uc.clone(),
+                    applicability: if can_change_usages {
+                        Applicability::MachineApplicable
+                    } else {
+                        Applicability::MaybeIncorrect
+                    },
+                }
             } else {
                 NonUpperCaseGlobalSub::Label { span: ident.span }
             };
 
             struct UsageCollector<'a, 'tcx> {
                 cx: &'tcx LateContext<'a>,
-                did: LocalDefId,
+                did: DefId,
                 collected: Vec<Span>,
             }
 
@@ -521,21 +539,23 @@ impl NonUpperCaseGlobals {
                     path: &rustc_hir::Path<'v>,
                     _id: rustc_hir::HirId,
                 ) -> Self::Result {
-                    for seg in path.segments {
-                        if seg.res.opt_def_id() == Some(self.did.to_def_id()) {
-                            self.collected.push(seg.ident.span);
-                        }
+                    if let Some(final_seg) = path.segments.last()
+                        && final_seg.res.opt_def_id() == Some(self.did)
+                    {
+                        self.collected.push(final_seg.ident.span);
                     }
                 }
             }
 
             cx.emit_span_lint_lazy(NON_UPPER_CASE_GLOBALS, ident.span, || {
                 // Compute usages lazily as it can expansive and useless when the lint is allowed.
                 // cf. https://github.com/rust-lang/rust/pull/142645#issuecomment-2993024625
-                let usages = if let Some(did) = did
+                let usages = if can_change_usages
                     && *name != uc
+                    && let Some(did) = did
                 {
-                    let mut usage_collector = UsageCollector { cx, did, collected: Vec::new() };
+                    let mut usage_collector =
+                        UsageCollector { cx, did: did.to_def_id(), collected: Vec::new() };
                     cx.tcx.hir_walk_toplevel_module(&mut usage_collector);
                     usage_collector
                         .collected

tests/ui/lint/lint-non-uppercase-usages.fixed

@@ -15,6 +15,11 @@ const MY_STATIC: u32 = 0;
 const LOL: u32 = MY_STATIC + 0;
 //~^ SUGGESTION MY_STATIC
 
+mod my_mod {
+    const INSIDE_MOD: u32 = super::MY_STATIC + 0;
+    //~^ SUGGESTION MY_STATIC
+}
+
 thread_local! {
     static FOO_FOO: Cell<usize> = unreachable!();
     //~^ WARN constant `fooFOO` should have an upper case name

tests/ui/lint/lint-non-uppercase-usages.rs

@@ -15,6 +15,11 @@ const my_static: u32 = 0;
 const LOL: u32 = my_static + 0;
 //~^ SUGGESTION MY_STATIC
 
+mod my_mod {
+    const INSIDE_MOD: u32 = super::my_static + 0;
+    //~^ SUGGESTION MY_STATIC
+}
+
 thread_local! {
     static fooFOO: Cell<usize> = unreachable!();
     //~^ WARN constant `fooFOO` should have an upper case name

tests/ui/lint/lint-non-uppercase-usages.stderr

@@ -12,7 +12,7 @@ LL + const MY_STATIC: u32 = 0;
    |
 
 warning: constant `fooFOO` should have an upper case name
-  --> $DIR/lint-non-uppercase-usages.rs:19:12
+  --> $DIR/lint-non-uppercase-usages.rs:24:12
    |
 LL |     static fooFOO: Cell<usize> = unreachable!();
    |            ^^^^^^
@@ -24,7 +24,7 @@ LL +     static FOO_FOO: Cell<usize> = unreachable!();
    |
 
 warning: const parameter `foo` should have an upper case name
-  --> $DIR/lint-non-uppercase-usages.rs:24:14
+  --> $DIR/lint-non-uppercase-usages.rs:29:14
    |
 LL | fn foo<const foo: u32>() {
    |              ^^^