Auto merge of #6787 - matthiaskrgr:lint_msgs, r=llogiq

tests: add test that roughly ensures that our lint messages conform with the diagnostics convention of the rustc dev guide

lint message should not start with uppercase letters
lint messages should not have punctuation at the end of the last line

https://rustc-dev-guide.rust-lang.org/diagnostics.html#diagnostic-structure

The test reads through all the .stderr files in the testsuit and checks lint messages that start with "help: ", "error: " etc.
There is also an exception list for special messages that are deemed acceptable.

changelog: make sure lint messages conform with the rustc dev guide and add test

Author: bors

Cargo.toml

@@ -42,6 +42,7 @@ tester = "0.9"
 clippy-mini-macro-test = { version = "0.2", path = "mini-macro" }
 serde = { version = "1.0", features = ["derive"] }
 derive-new = "0.5"
+regex = "1.4"
 
 # A noop dependency that changes in the Rust repository, it's a bit of a hack.
 # See the `src/tools/rustc-workspace-hack/README.md` file in `rust-lang/rust`

clippy_lints/src/assign_ops.rs

@@ -209,7 +209,7 @@ fn lint_misrefactored_assign_op(
                 diag.span_suggestion(
                     expr.span,
                     &format!(
-                        "Did you mean `{} = {} {} {}` or `{}`? Consider replacing it with",
+                        "did you mean `{} = {} {} {}` or `{}`? Consider replacing it with",
                         snip_a,
                         snip_a,
                         op.node.as_str(),

clippy_lints/src/attrs.rs

@@ -639,7 +639,7 @@ fn check_mismatched_target_os(cx: &EarlyContext<'_>, attr: &Attribute) {
                     diag.span_suggestion(span, "try", sugg, Applicability::MaybeIncorrect);
 
                     if !unix_suggested && is_unix(os) {
-                        diag.help("Did you mean `unix`?");
+                        diag.help("did you mean `unix`?");
                         unix_suggested = true;
                     }
                 }

clippy_lints/src/await_holding_invalid.rs

@@ -116,7 +116,7 @@ fn check_interior_types(cx: &LateContext<'_>, ty_causes: &[GeneratorInteriorType
                     cx,
                     AWAIT_HOLDING_LOCK,
                     ty_cause.span,
-                    "this MutexGuard is held across an 'await' point. Consider using an async-aware Mutex type or ensuring the MutexGuard is dropped before calling await.",
+                    "this MutexGuard is held across an 'await' point. Consider using an async-aware Mutex type or ensuring the MutexGuard is dropped before calling await",
                     ty_cause.scope_span.or(Some(span)),
                     "these are all the await points this lock is held through",
                 );
@@ -126,7 +126,7 @@ fn check_interior_types(cx: &LateContext<'_>, ty_causes: &[GeneratorInteriorType
                         cx,
                         AWAIT_HOLDING_REFCELL_REF,
                         ty_cause.span,
-                        "this RefCell Ref is held across an 'await' point. Consider ensuring the Ref is dropped before calling await.",
+                        "this RefCell Ref is held across an 'await' point. Consider ensuring the Ref is dropped before calling await",
                         ty_cause.scope_span.or(Some(span)),
                         "these are all the await points this ref is held through",
                     );

clippy_lints/src/comparison_chain.rs

@@ -117,7 +117,7 @@ impl<'tcx> LateLintPass<'tcx> for ComparisonChain {
             expr.span,
             "`if` chain can be rewritten with `match`",
             None,
-            "Consider rewriting the `if` chain to use `cmp` and `match`.",
+            "consider rewriting the `if` chain to use `cmp` and `match`",
         )
     }
 }

clippy_lints/src/drop_forget_ref.rs

@@ -98,13 +98,13 @@ declare_clippy_lint! {
 }
 
 const DROP_REF_SUMMARY: &str = "calls to `std::mem::drop` with a reference instead of an owned value. \
-                                Dropping a reference does nothing.";
+                                Dropping a reference does nothing";
 const FORGET_REF_SUMMARY: &str = "calls to `std::mem::forget` with a reference instead of an owned value. \
-                                  Forgetting a reference does nothing.";
+                                  Forgetting a reference does nothing";
 const DROP_COPY_SUMMARY: &str = "calls to `std::mem::drop` with a value that implements `Copy`. \
-                                 Dropping a copy leaves the original intact.";
+                                 Dropping a copy leaves the original intact";
 const FORGET_COPY_SUMMARY: &str = "calls to `std::mem::forget` with a value that implements `Copy`. \
-                                   Forgetting a copy leaves the original intact.";
+                                   Forgetting a copy leaves the original intact";
 
 declare_lint_pass!(DropForgetRef => [DROP_REF, FORGET_REF, DROP_COPY, FORGET_COPY]);
 

clippy_lints/src/fallible_impl_from.rs

@@ -133,7 +133,7 @@ fn lint_impl_body<'tcx>(cx: &LateContext<'tcx>, impl_span: Span, impl_items: &[h
                         move |diag| {
                             diag.help(
                                 "`From` is intended for infallible conversions only. \
-                                Use `TryFrom` if there's a possibility for the conversion to fail.");
+                                Use `TryFrom` if there's a possibility for the conversion to fail");
                             diag.span_note(fpu.result, "potential failure(s)");
                         });
                 }

clippy_lints/src/indexing_slicing.rs

@@ -132,13 +132,13 @@ impl<'tcx> LateLintPass<'tcx> for IndexingSlicing {
                 }
 
                 let help_msg = match (range.start, range.end) {
-                    (None, Some(_)) => "Consider using `.get(..n)`or `.get_mut(..n)` instead",
-                    (Some(_), None) => "Consider using `.get(n..)` or .get_mut(n..)` instead",
-                    (Some(_), Some(_)) => "Consider using `.get(n..m)` or `.get_mut(n..m)` instead",
+                    (None, Some(_)) => "consider using `.get(..n)`or `.get_mut(..n)` instead",
+                    (Some(_), None) => "consider using `.get(n..)` or .get_mut(n..)` instead",
+                    (Some(_), Some(_)) => "consider using `.get(n..m)` or `.get_mut(n..m)` instead",
                     (None, None) => return, // [..] is ok.
                 };
 
-                span_lint_and_help(cx, INDEXING_SLICING, expr.span, "slicing may panic.", None, help_msg);
+                span_lint_and_help(cx, INDEXING_SLICING, expr.span, "slicing may panic", None, help_msg);
             } else {
                 // Catchall non-range index, i.e., [n] or [n << m]
                 if let ty::Array(..) = ty.kind() {
@@ -153,9 +153,9 @@ impl<'tcx> LateLintPass<'tcx> for IndexingSlicing {
                     cx,
                     INDEXING_SLICING,
                     expr.span,
-                    "indexing may panic.",
+                    "indexing may panic",
                     None,
-                    "Consider using `.get(n)` or `.get_mut(n)` instead",
+                    "consider using `.get(n)` or `.get_mut(n)` instead",
                 );
             }
         }

clippy_lints/src/integer_division.rs

@@ -39,7 +39,7 @@ impl<'tcx> LateLintPass<'tcx> for IntegerDivision {
                 expr.span,
                 "integer division",
                 None,
-                "division of integers may cause loss of precision. consider using floats.",
+                "division of integers may cause loss of precision. consider using floats",
             );
         }
     }

clippy_lints/src/loops.rs

@@ -1625,10 +1625,7 @@ fn check_for_loop_range<'tcx>(
                         cx,
                         NEEDLESS_RANGE_LOOP,
                         expr.span,
-                        &format!(
-                            "the loop variable `{}` is only used to index `{}`.",
-                            ident.name, indexed
-                        ),
+                        &format!("the loop variable `{}` is only used to index `{}`", ident.name, indexed),
                         |diag| {
                             multispan_sugg(
                                 diag,
@@ -1763,7 +1760,7 @@ fn check_arg_type(cx: &LateContext<'_>, pat: &Pat<'_>, arg: &Expr<'_>) {
             arg.span,
             &format!(
                 "for loop over `{0}`, which is an `Option`. This is more readably written as an \
-                `if let` statement.",
+                `if let` statement",
                 snippet(cx, arg.span, "_")
             ),
             None,
@@ -1780,7 +1777,7 @@ fn check_arg_type(cx: &LateContext<'_>, pat: &Pat<'_>, arg: &Expr<'_>) {
             arg.span,
             &format!(
                 "for loop over `{0}`, which is a `Result`. This is more readably written as an \
-                `if let` statement.",
+                `if let` statement",
                 snippet(cx, arg.span, "_")
             ),
             None,
@@ -1826,7 +1823,7 @@ fn check_for_loop_explicit_counter<'tcx>(
                         cx,
                         EXPLICIT_COUNTER_LOOP,
                         for_span.with_hi(arg.span.hi()),
-                        &format!("the variable `{}` is used as a loop counter.", name),
+                        &format!("the variable `{}` is used as a loop counter", name),
                         "consider using",
                         format!(
                             "for ({}, {}) in {}.enumerate()",
@@ -3055,16 +3052,16 @@ impl IterFunction {
     fn get_suggestion_text(&self) -> &'static str {
         match &self.func {
             IterFunctionKind::IntoIter => {
-                "Use the original Iterator instead of collecting it and then producing a new one"
+                "use the original Iterator instead of collecting it and then producing a new one"
             },
             IterFunctionKind::Len => {
-                "Take the original Iterator's count instead of collecting it and finding the length"
+                "take the original Iterator's count instead of collecting it and finding the length"
             },
             IterFunctionKind::IsEmpty => {
-                "Check if the original Iterator has anything instead of collecting it and seeing if it's empty"
+                "check if the original Iterator has anything instead of collecting it and seeing if it's empty"
             },
             IterFunctionKind::Contains(_) => {
-                "Check if the original Iterator contains an element instead of collecting then checking"
+                "check if the original Iterator contains an element instead of collecting then checking"
             },
         }
     }