Bring attention to suggestions when the only difference is capitalization

38 files changed, 121 insertions, 71 deletions

diff --git a/src/librustc/session/config.rs b/src/librustc/session/config.rs
index 25e68e6408d..e7542029ac6 100644
--- a/src/librustc/session/config.rs
+++ b/src/librustc/session/config.rs
@@ -23,7 +23,7 @@ use syntax::feature_gate::UnstableFeatures;
 use syntax::source_map::SourceMap;
 
 use errors::emitter::HumanReadableErrorType;
-use errors::{ColorConfig, FatalError, Handler};
+use errors::{ColorConfig, FatalError, Handler, SourceMapperDyn};
 
 use getopts;
 
@@ -1854,6 +1854,7 @@ struct NullEmitter;
 
 impl errors::emitter::Emitter for NullEmitter {
     fn emit_diagnostic(&mut self, _: &errors::Diagnostic) {}
+    fn source_map(&self) -> Option<&Lrc<SourceMapperDyn>> { None }
 }
 
 // Converts strings provided as `--cfg [cfgspec]` into a `crate_cfg`.
diff --git a/src/librustc_codegen_ssa/back/write.rs b/src/librustc_codegen_ssa/back/write.rs
index 481db26e1a8..ef3b115890f 100644
--- a/src/librustc_codegen_ssa/back/write.rs
+++ b/src/librustc_codegen_ssa/back/write.rs
@@ -22,7 +22,8 @@ use rustc::util::common::{time_depth, set_time_depth, print_time_passes_entry};
 use rustc::util::profiling::SelfProfilerRef;
 use rustc_fs_util::link_or_copy;
 use rustc_data_structures::svh::Svh;
-use rustc_errors::{Handler, Level, FatalError, DiagnosticId};
+use rustc_data_structures::sync::Lrc;
+use rustc_errors::{Handler, Level, FatalError, DiagnosticId, SourceMapperDyn};
 use rustc_errors::emitter::{Emitter};
 use rustc_target::spec::MergeFunctions;
 use syntax::attr;
@@ -1681,6 +1682,9 @@ impl Emitter for SharedEmitter {
         }
         drop(self.sender.send(SharedEmitterMessage::AbortIfErrors));
     }
+    fn source_map(&self) -> Option<&Lrc<SourceMapperDyn>> {
+        None
+    }
 }
 
 impl SharedEmitterMain {
diff --git a/src/librustc_errors/annotate_snippet_emitter_writer.rs b/src/librustc_errors/annotate_snippet_emitter_writer.rs
index 0281d10fd93..16a1a28cd3a 100644
--- a/src/librustc_errors/annotate_snippet_emitter_writer.rs
+++ b/src/librustc_errors/annotate_snippet_emitter_writer.rs
@@ -49,6 +49,10 @@ impl Emitter for AnnotateSnippetEmitterWriter {
                                    &suggestions);
     }
 
+    fn source_map(&self) -> Option<&Lrc<SourceMapperDyn>> {
+        self.source_map.as_ref()
+    }
+
     fn should_show_explain(&self) -> bool {
         !self.short_message
     }
diff --git a/src/librustc_errors/emitter.rs b/src/librustc_errors/emitter.rs
index 68f933363da..04084453768 100644
--- a/src/librustc_errors/emitter.rs
+++ b/src/librustc_errors/emitter.rs
@@ -192,6 +192,8 @@ pub trait Emitter {
         true
     }
 
+    fn source_map(&self) -> Option<&Lrc<SourceMapperDyn>>;
+
     /// Formats the substitutions of the primary_span
     ///
     /// The are a lot of conditions to this method, but in short:
@@ -204,7 +206,7 @@ pub trait Emitter {
     ///   we return the original `primary_span` and the original suggestions.
     fn primary_span_formatted<'a>(
         &mut self,
-        db: &'a Diagnostic
+        db: &'a Diagnostic,
     ) -> (MultiSpan, &'a [CodeSuggestion]) {
         let mut primary_span = db.span.clone();
         if let Some((sugg, rest)) = db.suggestions.split_first() {
@@ -234,7 +236,20 @@ pub trait Emitter {
                     format!("help: {}", sugg.msg)
                 } else {
                     // Show the default suggestion text with the substitution
-                    format!("help: {}: `{}`", sugg.msg, substitution)
+                    format!(
+                        "help: {}{}: `{}`",
+                        sugg.msg,
+                        if self.source_map().as_ref().map(|sm| substitution.to_lowercase() == sm
+                            .span_to_snippet(sugg.substitutions[0].parts[0].span)
+                            .unwrap()
+                            .to_lowercase()).unwrap_or(false)
+                        {
+                            " (notice the capitalization)"
+                        } else {
+                            ""
+                        },
+                        substitution,
+                    )
                 };
                 primary_span.push_span_label(sugg.substitutions[0].parts[0].span, msg);
 
@@ -382,6 +397,10 @@ pub trait Emitter {
 }
 
 impl Emitter for EmitterWriter {
+    fn source_map(&self) -> Option<&Lrc<SourceMapperDyn>> {
+        self.sm.as_ref()
+    }
+
     fn emit_diagnostic(&mut self, db: &Diagnostic) {
         let mut children = db.children.clone();
         let (mut primary_span, suggestions) = self.primary_span_formatted(&db);
@@ -1461,7 +1480,9 @@ impl EmitterWriter {
         let suggestions = suggestion.splice_lines(&**sm);
 
         let mut row_num = 2;
-        for &(ref complete, ref parts) in suggestions.iter().take(MAX_SUGGESTIONS) {
+        let mut notice_capitalization = false;
+        for (complete, parts, only_capitalization) in suggestions.iter().take(MAX_SUGGESTIONS) {
+            notice_capitalization |= only_capitalization;
             // Only show underline if the suggestion spans a single line and doesn't cover the
             // entirety of the code output. If you have multiple replacements in the same line
             // of code, show the underline.
@@ -1552,7 +1573,10 @@ impl EmitterWriter {
         }
         if suggestions.len() > MAX_SUGGESTIONS {
             let msg = format!("and {} other candidates", suggestions.len() - MAX_SUGGESTIONS);
-            buffer.puts(row_num, 0, &msg, Style::NoStyle);
+            buffer.puts(row_num, max_line_num_len + 3, &msg, Style::NoStyle);
+        } else if notice_capitalization {
+            let msg = "notice the capitalization difference";
+            buffer.puts(row_num, max_line_num_len + 3, &msg, Style::NoStyle);
         }
         emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
         Ok(())
diff --git a/src/librustc_errors/lib.rs b/src/librustc_errors/lib.rs
index 2fae584c153..babaeb7e532 100644
--- a/src/librustc_errors/lib.rs
+++ b/src/librustc_errors/lib.rs
@@ -37,13 +37,16 @@ pub mod registry;
 mod styled_buffer;
 mod lock;
 
-use syntax_pos::{BytePos,
-                 Loc,
-                 FileLinesResult,
-                 SourceFile,
-                 FileName,
-                 MultiSpan,
-                 Span};
+use syntax_pos::{
+    BytePos,
+    FileLinesResult,
+    FileName,
+    Loc,
+    MultiSpan,
+    SourceFile,
+    Span,
+    SpanSnippetError,
+};
 
 /// Indicates the confidence in the correctness of a suggestion.
 ///
@@ -147,6 +150,7 @@ pub trait SourceMapper {
     fn lookup_char_pos(&self, pos: BytePos) -> Loc;
     fn span_to_lines(&self, sp: Span) -> FileLinesResult;
     fn span_to_string(&self, sp: Span) -> String;
+    fn span_to_snippet(&self, sp: Span) -> Result<String, SpanSnippetError>;
     fn span_to_filename(&self, sp: Span) -> FileName;
     fn merge_spans(&self, sp_lhs: Span, sp_rhs: Span) -> Option<Span>;
     fn call_span_if_macro(&self, sp: Span) -> Span;
@@ -155,9 +159,12 @@ pub trait SourceMapper {
 }
 
 impl CodeSuggestion {
-    /// Returns the assembled code suggestions and whether they should be shown with an underline.
-    pub fn splice_lines(&self, cm: &SourceMapperDyn)
-                        -> Vec<(String, Vec<SubstitutionPart>)> {
+    /// Returns the assembled code suggestions, whether they should be shown with an underline
+    /// and whether the substitution only differs in capitalization.
+    pub fn splice_lines(
+        &self,
+        cm: &SourceMapperDyn,
+    ) -> Vec<(String, Vec<SubstitutionPart>, bool)> {
         use syntax_pos::{CharPos, Pos};
 
         fn push_trailing(buf: &mut String,
@@ -232,6 +239,8 @@ impl CodeSuggestion {
                 prev_hi = cm.lookup_char_pos(part.span.hi());
                 prev_line = fm.get_line(prev_hi.line - 1);
             }
+            let only_capitalization = buf.clone().to_lowercase()
+                == cm.span_to_snippet(bounding_span).unwrap().to_lowercase();
             // if the replacement already ends with a newline, don't print the next line
             if !buf.ends_with('\n') {
                 push_trailing(&mut buf, prev_line.as_ref(), &prev_hi, None);
@@ -240,7 +249,8 @@ impl CodeSuggestion {
             while buf.ends_with('\n') {
                 buf.pop();
             }
-            (buf, substitution.parts)
+            (buf, substitution.parts, only_capitalization)
+            
         }).collect()
     }
 }
diff --git a/src/libsyntax/json.rs b/src/libsyntax/json.rs
index 2423e1070fc..4cf987417b8 100644
--- a/src/libsyntax/json.rs
+++ b/src/libsyntax/json.rs
@@ -12,7 +12,7 @@
 use crate::source_map::{SourceMap, FilePathMapping};
 
 use errors::registry::Registry;
-use errors::{SubDiagnostic, CodeSuggestion, SourceMapper};
+use errors::{SubDiagnostic, CodeSuggestion, SourceMapper, SourceMapperDyn};
 use errors::{DiagnosticId, Applicability};
 use errors::emitter::{Emitter, HumanReadableErrorType};
 
@@ -113,6 +113,10 @@ impl Emitter for JsonEmitter {
         }
     }
 
+    fn source_map(&self) -> Option<&Lrc<SourceMapperDyn>> {
+        Some(&self.sm)
+    }
+
     fn should_show_explain(&self) -> bool {
         match self.json_rendered {
             HumanReadableErrorType::Short(_) => false,
diff --git a/src/libsyntax/source_map.rs b/src/libsyntax/source_map.rs
index 7d0d2392945..f6ba75dd5b5 100644
--- a/src/libsyntax/source_map.rs
+++ b/src/libsyntax/source_map.rs
@@ -987,6 +987,9 @@ impl SourceMapper for SourceMap {
     fn span_to_string(&self, sp: Span) -> String {
         self.span_to_string(sp)
     }
+    fn span_to_snippet(&self, sp: Span) -> Result<String, SpanSnippetError> {
+        self.span_to_snippet(sp)
+    }
     fn span_to_filename(&self, sp: Span) -> FileName {
         self.span_to_filename(sp)
     }
diff --git a/src/test/ui/const-generics/const-parameter-uppercase-lint.stderr b/src/test/ui/const-generics/const-parameter-uppercase-lint.stderr
index fddb06981bc..32cf8d8a01a 100644
--- a/src/test/ui/const-generics/const-parameter-uppercase-lint.stderr
+++ b/src/test/ui/const-generics/const-parameter-uppercase-lint.stderr
@@ -10,7 +10,7 @@ error: const parameter `x` should have an upper case name
   --> $DIR/const-parameter-uppercase-lint.rs:6:15
    |
 LL | fn noop<const x: u32>() {
-   |               ^ help: convert the identifier to upper case: `X`
+   |               ^ help: convert the identifier to upper case (notice the capitalization): `X`
    |
 note: lint level defined here
   --> $DIR/const-parameter-uppercase-lint.rs:4:9
diff --git a/src/test/ui/consts/const-eval/const_fn_ptr.stderr b/src/test/ui/consts/const-eval/const_fn_ptr.stderr
index 2fbb1932244..9a5871905a0 100644
--- a/src/test/ui/consts/const-eval/const_fn_ptr.stderr
+++ b/src/test/ui/consts/const-eval/const_fn_ptr.stderr
@@ -20,7 +20,7 @@ warning: constant `X_const` should have an upper case name
   --> $DIR/const_fn_ptr.rs:9:7
    |
 LL | const X_const: fn(usize) -> usize = double_const;
-   |       ^^^^^^^ help: convert the identifier to upper case: `X_CONST`
+   |       ^^^^^^^ help: convert the identifier to upper case (notice the capitalization): `X_CONST`
    |
    = note: `#[warn(non_upper_case_globals)]` on by default
 
diff --git a/src/test/ui/did_you_mean/issue-43871-enum-instead-of-variant.stderr b/src/test/ui/did_you_mean/issue-43871-enum-instead-of-variant.stderr
index d8826d4072a..ef68bf52cf3 100644
--- a/src/test/ui/did_you_mean/issue-43871-enum-instead-of-variant.stderr
+++ b/src/test/ui/did_you_mean/issue-43871-enum-instead-of-variant.stderr
@@ -55,7 +55,7 @@ LL |     let z = ManyVariants::Three();
    |             ^^^^^^^^^^^^^^^^^^^
 LL |     let z = ManyVariants::Four();
    |             ^^^^^^^^^^^^^^^^^^
-and 6 other candidates
+     and 6 other candidates
 
 error: aborting due to 5 previous errors
 
diff --git a/src/test/ui/did_you_mean/issue-56028-there-is-an-enum-variant.stderr b/src/test/ui/did_you_mean/issue-56028-there-is-an-enum-variant.stderr
index 8d3a86df023..cb350a1faee 100644
--- a/src/test/ui/did_you_mean/issue-56028-there-is-an-enum-variant.stderr
+++ b/src/test/ui/did_you_mean/issue-56028-there-is-an-enum-variant.stderr
@@ -13,7 +13,7 @@ LL | fn setup() -> Determine { Set }
    |               ^^^^^^^^^
 LL | fn setup() -> PutDown { Set }
    |               ^^^^^^^
-and 3 other candidates
+     and 3 other candidates
 
 error[E0425]: cannot find value `Set` in this scope
   --> $DIR/issue-56028-there-is-an-enum-variant.rs:9:21
@@ -30,7 +30,7 @@ LL | use Determine::Set;
    |
 LL | use PutDown::Set;
    |
-and 3 other candidates
+     and 3 other candidates
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/enable-unstable-lib-feature.stderr b/src/test/ui/enable-unstable-lib-feature.stderr
index d5b8c0efaad..d89f804f15b 100644
--- a/src/test/ui/enable-unstable-lib-feature.stderr
+++ b/src/test/ui/enable-unstable-lib-feature.stderr
@@ -2,7 +2,7 @@ error: function `BOGUS` should have a snake case name
   --> $DIR/enable-unstable-lib-feature.rs:11:8
    |
 LL | pub fn BOGUS() { }
-   |        ^^^^^ help: convert the identifier to snake case: `bogus`
+   |        ^^^^^ help: convert the identifier to snake case (notice the capitalization): `bogus`
    |
 note: lint level defined here
   --> $DIR/enable-unstable-lib-feature.rs:6:9
diff --git a/src/test/ui/error-codes/E0423.stderr b/src/test/ui/error-codes/E0423.stderr
index ce631ca4bf7..754006bc217 100644
--- a/src/test/ui/error-codes/E0423.stderr
+++ b/src/test/ui/error-codes/E0423.stderr
@@ -34,7 +34,7 @@ LL |     let f = Foo();
    |             ^^^
    |             |
    |             did you mean `Foo { /* fields */ }`?
-   |             help: a function with a similar name exists: `foo`
+   |             help: a function with a similar name exists (notice the capitalization): `foo`
 
 error[E0423]: expected value, found struct `T`
   --> $DIR/E0423.rs:14:8
diff --git a/src/test/ui/expr_attr_paren_order.stderr b/src/test/ui/expr_attr_paren_order.stderr
index 89f615f53dd..57a9350c089 100644
--- a/src/test/ui/expr_attr_paren_order.stderr
+++ b/src/test/ui/expr_attr_paren_order.stderr
@@ -2,7 +2,7 @@ error: variable `X` should have a snake case name
   --> $DIR/expr_attr_paren_order.rs:19:17
    |
 LL |             let X = 0;
-   |                 ^ help: convert the identifier to snake case: `x`
+   |                 ^ help: convert the identifier to snake case (notice the capitalization): `x`
    |
 note: lint level defined here
   --> $DIR/expr_attr_paren_order.rs:17:17
diff --git a/src/test/ui/hygiene/extern-prelude-from-opaque-fail.stderr b/src/test/ui/hygiene/extern-prelude-from-opaque-fail.stderr
index 65133eb1e18..1f5e46c133d 100644
--- a/src/test/ui/hygiene/extern-prelude-from-opaque-fail.stderr
+++ b/src/test/ui/hygiene/extern-prelude-from-opaque-fail.stderr
@@ -5,7 +5,7 @@ LL |     use my_core;
    |         ^^^^^^^
    |         |
    |         no `my_core` in the root
-   |         help: a similar name exists in the module: `my_core`
+   |         help: a similar name exists in the module (notice the capitalization): `my_core`
 
 error[E0432]: unresolved import `my_core`
   --> $DIR/extern-prelude-from-opaque-fail.rs:7:13
diff --git a/src/test/ui/hygiene/globs.stderr b/src/test/ui/hygiene/globs.stderr
index 7e0f4e4e0b8..7acb266f49c 100644
--- a/src/test/ui/hygiene/globs.stderr
+++ b/src/test/ui/hygiene/globs.stderr
@@ -34,7 +34,7 @@ LL | use foo::test2::test::g;
    |
 LL | use foo::test::g;
    |
-and 2 other candidates
+     and 2 other candidates
 
 error[E0425]: cannot find function `f` in this scope
   --> $DIR/globs.rs:61:12
diff --git a/src/test/ui/hygiene/rustc-macro-transparency.stderr b/src/test/ui/hygiene/rustc-macro-transparency.stderr
index 5eacfdf8dee..45a2efebbb8 100644
--- a/src/test/ui/hygiene/rustc-macro-transparency.stderr
+++ b/src/test/ui/hygiene/rustc-macro-transparency.stderr
@@ -2,7 +2,7 @@ error[E0425]: cannot find value `Opaque` in this scope
   --> $DIR/rustc-macro-transparency.rs:26:5
    |
 LL |     Opaque;
-   |     ^^^^^^ help: a local variable with a similar name exists: `opaque`
+   |     ^^^^^^ help: a local variable with a similar name exists (notice the capitalization): `opaque`
 
 error[E0423]: expected value, found macro `semitransparent`
   --> $DIR/rustc-macro-transparency.rs:29:5
diff --git a/src/test/ui/issues/issue-10200.stderr b/src/test/ui/issues/issue-10200.stderr
index 544716e89b3..b1057d45869 100644
--- a/src/test/ui/issues/issue-10200.stderr
+++ b/src/test/ui/issues/issue-10200.stderr
@@ -2,7 +2,7 @@ error[E0532]: expected tuple struct/variant, found function `foo`
   --> $DIR/issue-10200.rs:6:9
    |
 LL |         foo(x)
-   |         ^^^ help: a tuple struct with a similar name exists: `Foo`
+   |         ^^^ help: a tuple struct with a similar name exists (notice the capitalization): `Foo`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-17546.stderr b/src/test/ui/issues/issue-17546.stderr
index e27f49b4a3f..1f71e159f18 100644
--- a/src/test/ui/issues/issue-17546.stderr
+++ b/src/test/ui/issues/issue-17546.stderr
@@ -27,7 +27,7 @@ LL |     use std::prelude::v1::Result;
    |
 LL |     use std::result::Result;
    |
-and 1 other candidates
+     and 1 other candidates
 
 error[E0573]: expected type, found variant `Result`
   --> $DIR/issue-17546.rs:28:13
@@ -44,7 +44,7 @@ LL | use std::prelude::v1::Result;
    |
 LL | use std::result::Result;
    |
-and 1 other candidates
+     and 1 other candidates
 
 error[E0573]: expected type, found variant `NoResult`
   --> $DIR/issue-17546.rs:33:15
diff --git a/src/test/ui/issues/issue-17718-const-naming.stderr b/src/test/ui/issues/issue-17718-const-naming.stderr
index 1fe1821292c..e320c436f5b 100644
--- a/src/test/ui/issues/issue-17718-const-naming.stderr
+++ b/src/test/ui/issues/issue-17718-const-naming.stderr
@@ -15,7 +15,7 @@ error: constant `foo` should have an upper case name
   --> $DIR/issue-17718-const-naming.rs:4:7
    |
 LL | const foo: isize = 3;
-   |       ^^^ help: convert the identifier to upper case: `FOO`
+   |       ^^^ help: convert the identifier to upper case (notice the capitalization): `FOO`
    |
 note: lint level defined here
   --> $DIR/issue-17718-const-naming.rs:2:9
diff --git a/src/test/ui/issues/issue-46332.stderr b/src/test/ui/issues/issue-46332.stderr
index 812a50000d1..c7e9d71700e 100644
--- a/src/test/ui/issues/issue-46332.stderr
+++ b/src/test/ui/issues/issue-46332.stderr
@@ -2,7 +2,7 @@ error[E0422]: cannot find struct, variant or union type `TyUInt` in this scope
   --> $DIR/issue-46332.rs:9:5
    |
 LL |     TyUInt {};
-   |     ^^^^^^ help: a struct with a similar name exists: `TyUint`
+   |     ^^^^^^ help: a struct with a similar name exists (notice the capitalization): `TyUint`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/lint/lint-group-nonstandard-style.stderr b/src/test/ui/lint/lint-group-nonstandard-style.stderr
index 1cc973d32c2..1ecd0f38826 100644
--- a/src/test/ui/lint/lint-group-nonstandard-style.stderr
+++ b/src/test/ui/lint/lint-group-nonstandard-style.stderr
@@ -41,7 +41,7 @@ error: static variable `bad` should have an upper case name
   --> $DIR/lint-group-nonstandard-style.rs:14:16
    |
 LL |         static bad: isize = 1;
-   |                ^^^ help: convert the identifier to upper case: `BAD`
+   |                ^^^ help: convert the identifier to upper case (notice the capitalization): `BAD`
    |
 note: lint level defined here
   --> $DIR/lint-group-nonstandard-style.rs:10:14
diff --git a/src/test/ui/lint/lint-lowercase-static-const-pattern.stderr b/src/test/ui/lint/lint-lowercase-static-const-pattern.stderr
index d95510ccd2d..5cac1c3d053 100644
--- a/src/test/ui/lint/lint-lowercase-static-const-pattern.stderr
+++ b/src/test/ui/lint/lint-lowercase-static-const-pattern.stderr
@@ -2,7 +2,7 @@ error: constant in pattern `a` should have an upper case name
   --> $DIR/lint-lowercase-static-const-pattern.rs:11:13
    |
 LL |         (0, a) => 0,
-   |             ^ help: convert the identifier to upper case: `A`
+   |             ^ help: convert the identifier to upper case (notice the capitalization): `A`
    |
 note: lint level defined here
   --> $DIR/lint-lowercase-static-const-pattern.rs:4:9
@@ -14,13 +14,13 @@ error: constant in pattern `aha` should have an upper case name
   --> $DIR/lint-lowercase-static-const-pattern.rs:26:13
    |
 LL |         (0, aha) => 0,
-   |             ^^^ help: convert the identifier to upper case: `AHA`
+   |             ^^^ help: convert the identifier to upper case (notice the capitalization): `AHA`
 
 error: constant in pattern `not_okay` should have an upper case name
   --> $DIR/lint-lowercase-static-const-pattern.rs:40:13
    |
 LL |         (0, not_okay) => 0,
-   |             ^^^^^^^^ help: convert the identifier to upper case: `NOT_OKAY`
+   |             ^^^^^^^^ help: convert the identifier to upper case (notice the capitalization): `NOT_OKAY`
 
 error: aborting due to 3 previous errors
 
diff --git a/src/test/ui/lint/lint-non-camel-case-types.stderr b/src/test/ui/lint/lint-non-camel-case-types.stderr
index 432a16debc6..02f7db045e5 100644
--- a/src/test/ui/lint/lint-non-camel-case-types.stderr
+++ b/src/test/ui/lint/lint-non-camel-case-types.stderr
@@ -14,43 +14,43 @@ error: type `foo` should have an upper camel case name
   --> $DIR/lint-non-camel-case-types.rs:7:8
    |
 LL | struct foo {
-   |        ^^^ help: convert the identifier to upper camel case: `Foo`
+   |        ^^^ help: convert the identifier to upper camel case (notice the capitalization): `Foo`
 
 error: type `foo2` should have an upper camel case name
   --> $DIR/lint-non-camel-case-types.rs:11:6
    |
 LL | enum foo2 {
-   |      ^^^^ help: convert the identifier to upper camel case: `Foo2`
+   |      ^^^^ help: convert the identifier to upper camel case (notice the capitalization): `Foo2`
 
 error: type `foo3` should have an upper camel case name
   --> $DIR/lint-non-camel-case-types.rs:15:8
    |
 LL | struct foo3 {
-   |        ^^^^ help: convert the identifier to upper camel case: `Foo3`
+   |        ^^^^ help: convert the identifier to upper camel case (notice the capitalization): `Foo3`
 
 error: type `foo4` should have an upper camel case name
   --> $DIR/lint-non-camel-case-types.rs:19:6
    |
 LL | type foo4 = isize;
-   |      ^^^^ help: convert the identifier to upper camel case: `Foo4`
+   |      ^^^^ help: convert the identifier to upper camel case (notice the capitalization): `Foo4`
 
 error: variant `bar` should have an upper camel case name
   --> $DIR/lint-non-camel-case-types.rs:22:5
    |
 LL |     bar
-   |     ^^^ help: convert the identifier to upper camel case: `Bar`
+   |     ^^^ help: convert the identifier to upper camel case (notice the capitalization): `Bar`
 
 error: trait `foo6` should have an upper camel case name
   --> $DIR/lint-non-camel-case-types.rs:25:7
    |
 LL | trait foo6 {
-   |       ^^^^ help: convert the identifier to upper camel case: `Foo6`
+   |       ^^^^ help: convert the identifier to upper camel case (notice the capitalization): `Foo6`
 
 error: type parameter `ty` should have an upper camel case name
   --> $DIR/lint-non-camel-case-types.rs:29:6
    |
 LL | fn f<ty>(_: ty) {}
-   |      ^^ help: convert the identifier to upper camel case: `Ty`
+   |      ^^ help: convert the identifier to upper camel case (notice the capitalization): `Ty`
 
 error: aborting due to 8 previous errors
 
diff --git a/src/test/ui/lint/lint-non-snake-case-functions.stderr b/src/test/ui/lint/lint-non-snake-case-functions.stderr
index 49cbfa94126..2e7b53b05d1 100644
--- a/src/test/ui/lint/lint-non-snake-case-functions.stderr
+++ b/src/test/ui/lint/lint-non-snake-case-functions.stderr
@@ -2,7 +2,7 @@ error: method `Foo_Method` should have a snake case name
   --> $DIR/lint-non-snake-case-functions.rs:7:8
    |
 LL |     fn Foo_Method() {}
-   |        ^^^^^^^^^^ help: convert the identifier to snake case: `foo_method`
+   |        ^^^^^^^^^^ help: convert the identifier to snake case (notice the capitalization): `foo_method`
    |
 note: lint level defined here
   --> $DIR/lint-non-snake-case-functions.rs:1:9
@@ -26,19 +26,19 @@ error: method `render_HTML` should have a snake case name
   --> $DIR/lint-non-snake-case-functions.rs:17:8
    |
 LL |     fn render_HTML() {}
-   |        ^^^^^^^^^^^ help: convert the identifier to snake case: `render_html`
+   |        ^^^^^^^^^^^ help: convert the identifier to snake case (notice the capitalization): `render_html`
 
 error: trait method `ABC` should have a snake case name
   --> $DIR/lint-non-snake-case-functions.rs:22:8
    |
 LL |     fn ABC();
-   |        ^^^ help: convert the identifier to snake case: `abc`
+   |        ^^^ help: convert the identifier to snake case (notice the capitalization): `abc`
 
 error: trait method `a_b_C` should have a snake case name
   --> $DIR/lint-non-snake-case-functions.rs:25:8
    |
 LL |     fn a_b_C(&self) {}
-   |        ^^^^^ help: convert the identifier to snake case: `a_b_c`
+   |        ^^^^^ help: convert the identifier to snake case (notice the capitalization): `a_b_c`
 
 error: trait method `something__else` should have a snake case name
   --> $DIR/lint-non-snake-case-functions.rs:28:8
@@ -50,13 +50,13 @@ error: function `Cookie` should have a snake case name
   --> $DIR/lint-non-snake-case-functions.rs:38:4
    |
 LL | fn Cookie() {}
-   |    ^^^^^^ help: convert the identifier to snake case: `cookie`
+   |    ^^^^^^ help: convert the identifier to snake case (notice the capitalization): `cookie`
 
 error: function `bi_S_Cuit` should have a snake case name
   --> $DIR/lint-non-snake-case-functions.rs:41:8
    |
 LL | pub fn bi_S_Cuit() {}
-   |        ^^^^^^^^^ help: convert the identifier to snake case: `bi_s_cuit`
+   |        ^^^^^^^^^ help: convert the identifier to snake case (notice the capitalization): `bi_s_cuit`
 
 error: aborting due to 9 previous errors
 
diff --git a/src/test/ui/lint/lint-non-uppercase-associated-const.stderr b/src/test/ui/lint/lint-non-uppercase-associated-const.stderr
index 2185d5a0ab4..233048ee1dd 100644
--- a/src/test/ui/lint/lint-non-uppercase-associated-const.stderr
+++ b/src/test/ui/lint/lint-non-uppercase-associated-const.stderr
@@ -2,7 +2,7 @@ error: associated constant `not_upper` should have an upper case name
   --> $DIR/lint-non-uppercase-associated-const.rs:7:11
    |
 LL |     const not_upper: bool = true;
-   |           ^^^^^^^^^ help: convert the identifier to upper case: `NOT_UPPER`
+   |           ^^^^^^^^^ help: convert the identifier to upper case (notice the capitalization): `NOT_UPPER`
    |
 note: lint level defined here
   --> $DIR/lint-non-uppercase-associated-const.rs:1:9
diff --git a/src/test/ui/lint/lint-non-uppercase-statics.stderr b/src/test/ui/lint/lint-non-uppercase-statics.stderr
index 8b477276efc..a03bdf52a0a 100644
--- a/src/test/ui/lint/lint-non-uppercase-statics.stderr
+++ b/src/test/ui/lint/lint-non-uppercase-statics.stderr
@@ -2,7 +2,7 @@ error: static variable `foo` should have an upper case name
   --> $DIR/lint-non-uppercase-statics.rs:4:8
    |
 LL | static foo: isize = 1;
-   |        ^^^ help: convert the identifier to upper case: `FOO`
+   |        ^^^ help: convert the identifier to upper case (notice the capitalization): `FOO`
    |
 note: lint level defined here
   --> $DIR/lint-non-uppercase-statics.rs:1:11
@@ -14,7 +14,7 @@ error: static variable `bar` should have an upper case name
   --> $DIR/lint-non-uppercase-statics.rs:6:12
    |
 LL | static mut bar: isize = 1;
-   |            ^^^ help: convert the identifier to upper case: `BAR`
+   |            ^^^ help: convert the identifier to upper case (notice the capitalization): `BAR`
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/lint/lint-uppercase-variables.stderr b/src/test/ui/lint/lint-uppercase-variables.stderr
index 9ea3795f89e..cc2be3d0bd9 100644
--- a/src/test/ui/lint/lint-uppercase-variables.stderr
+++ b/src/test/ui/lint/lint-uppercase-variables.stderr
@@ -21,7 +21,7 @@ error: structure field `X` should have a snake case name
   --> $DIR/lint-uppercase-variables.rs:10:5
    |
 LL |     X: usize
-   |     ^ help: convert the identifier to snake case: `x`
+   |     ^ help: convert the identifier to snake case (notice the capitalization): `x`
    |
 note: lint level defined here
   --> $DIR/lint-uppercase-variables.rs:3:9
@@ -33,19 +33,19 @@ error: variable `Xx` should have a snake case name
   --> $DIR/lint-uppercase-variables.rs:13:9
    |
 LL | fn test(Xx: usize) {
-   |         ^^ help: convert the identifier to snake case: `xx`
+   |         ^^ help: convert the identifier to snake case (notice the capitalization): `xx`
 
 error: variable `Test` should have a snake case name
   --> $DIR/lint-uppercase-variables.rs:18:9
    |
 LL |     let Test: usize = 0;
-   |         ^^^^ help: convert the identifier to snake case: `test`
+   |         ^^^^ help: convert the identifier to snake case (notice the capitalization): `test`
 
 error: variable `Foo` should have a snake case name
   --> $DIR/lint-uppercase-variables.rs:22:9
    |
 LL |         Foo => {}
-   |         ^^^ help: convert the identifier to snake case: `foo`
+   |         ^^^ help: convert the identifier to snake case (notice the capitalization): `foo`
 
 error: aborting due to 4 previous errors
 
diff --git a/src/test/ui/lint/not_found.stderr b/src/test/ui/lint/not_found.stderr
index 70d49a4e69c..8614e9f1173 100644
--- a/src/test/ui/lint/not_found.stderr
+++ b/src/test/ui/lint/not_found.stderr
@@ -10,11 +10,11 @@ warning: unknown lint: `DEAD_CODE`
   --> $DIR/not_found.rs:8:8
    |
 LL | #[warn(DEAD_CODE)]
-   |        ^^^^^^^^^ help: did you mean: `dead_code`
+   |        ^^^^^^^^^ help: did you mean (notice the capitalization): `dead_code`
 
 warning: unknown lint: `Warnings`
   --> $DIR/not_found.rs:10:8
    |
 LL | #[deny(Warnings)]
-   |        ^^^^^^^^ help: did you mean: `warnings`
+   |        ^^^^^^^^ help: did you mean (notice the capitalization): `warnings`
 
diff --git a/src/test/ui/lint/reasons.stderr b/src/test/ui/lint/reasons.stderr
index cb5f4ddf47b..139b3f13fd6 100644
--- a/src/test/ui/lint/reasons.stderr
+++ b/src/test/ui/lint/reasons.stderr
@@ -15,7 +15,7 @@ warning: variable `Social_exchange_psychology` should have a snake case name
   --> $DIR/reasons.rs:30:9
    |
 LL |     let Social_exchange_psychology = CheaterDetectionMechanism {};
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: convert the identifier to snake case: `social_exchange_psychology`
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: convert the identifier to snake case (notice the capitalization): `social_exchange_psychology`
    |
    = note: people shouldn't have to change their usual style habits
            to contribute to our project
diff --git a/src/test/ui/lint/use_suggestion_json.stderr b/src/test/ui/lint/use_suggestion_json.stderr
index 678c88849b5..1da5acc9661 100644
--- a/src/test/ui/lint/use_suggestion_json.stderr
+++ b/src/test/ui/lint/use_suggestion_json.stderr
@@ -395,7 +395,7 @@ mod foo {
 \u001b[0m   \u001b[0m\u001b[0m\u001b[1m\u001b[38;5;12m|\u001b[0m
 \u001b[0m\u001b[1m\u001b[38;5;12mLL\u001b[0m\u001b[0m \u001b[0m\u001b[0m\u001b[1m\u001b[38;5;12m| \u001b[0m\u001b[0muse std::collections::hash_map::Iter;\u001b[0m
 \u001b[0m   \u001b[0m\u001b[0m\u001b[1m\u001b[38;5;12m|\u001b[0m
-\u001b[0mand 8 other candidates\u001b[0m
+\u001b[0m     and 8 other candidates\u001b[0m
 
 "
 }
diff --git a/src/test/ui/resolve/issue-21221-1.stderr b/src/test/ui/resolve/issue-21221-1.stderr
index d00d87393aa..513e02f74e3 100644
--- a/src/test/ui/resolve/issue-21221-1.stderr
+++ b/src/test/ui/resolve/issue-21221-1.stderr
@@ -27,7 +27,7 @@ LL | use mul3::Mul;
    |
 LL | use mul4::Mul;
    |
-and 2 other candidates
+     and 2 other candidates
 
 error[E0405]: cannot find trait `ThisTraitReallyDoesntExistInAnyModuleReally` in this scope
   --> $DIR/issue-21221-1.rs:63:6
diff --git a/src/test/ui/resolve/issue-39226.stderr b/src/test/ui/resolve/issue-39226.stderr
index d9a28e63dce..ad596c25551 100644
--- a/src/test/ui/resolve/issue-39226.stderr
+++ b/src/test/ui/resolve/issue-39226.stderr
@@ -8,7 +8,7 @@ LL |         handle: Handle
    |                 ^^^^^^
    |                 |
    |                 did you mean `Handle { /* fields */ }`?
-   |                 help: a local variable with a similar name exists: `handle`
+   |                 help: a local variable with a similar name exists (notice the capitalization): `handle`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/resolve/levenshtein.stderr b/src/test/ui/resolve/levenshtein.stderr
index 2e3c0f5448e..e693a0ef91f 100644
--- a/src/test/ui/resolve/levenshtein.stderr
+++ b/src/test/ui/resolve/levenshtein.stderr
@@ -38,13 +38,13 @@ error[E0412]: cannot find type `first` in module `m`
   --> $DIR/levenshtein.rs:28:15
    |
 LL |     let b: m::first = m::second; // Misspelled item in module.
-   |               ^^^^^ help: a struct with a similar name exists: `First`
+   |               ^^^^^ help: a struct with a similar name exists (notice the capitalization): `First`
 
 error[E0425]: cannot find value `second` in module `m`
   --> $DIR/levenshtein.rs:28:26
    |
 LL |     let b: m::first = m::second; // Misspelled item in module.
-   |                          ^^^^^^ help: a unit struct with a similar name exists: `Second`
+   |                          ^^^^^^ help: a unit struct with a similar name exists (notice the capitalization): `Second`
 
 error: aborting due to 8 previous errors
 
diff --git a/src/test/ui/rust-2018/issue-52202-use-suggestions.stderr b/src/test/ui/rust-2018/issue-52202-use-suggestions.stderr
index 030fa56dcff..973c486970e 100644
--- a/src/test/ui/rust-2018/issue-52202-use-suggestions.stderr
+++ b/src/test/ui/rust-2018/issue-52202-use-suggestions.stderr
@@ -13,7 +13,7 @@ LL | use std::collections::hash_map::Drain;
    |
 LL | use std::collections::hash_set::Drain;
    |
-and 3 other candidates
+     and 3 other candidates
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/test-attrs/inaccessible-test-modules.stderr b/src/test/ui/test-attrs/inaccessible-test-modules.stderr
index a94ea1e79bc..0b94619f689 100644
--- a/src/test/ui/test-attrs/inaccessible-test-modules.stderr
+++ b/src/test/ui/test-attrs/inaccessible-test-modules.stderr
@@ -5,7 +5,7 @@ LL | use main as x;
    |     ----^^^^^
    |     |
    |     no `main` in the root
-   |     help: a similar name exists in the module: `main`
+   |     help: a similar name exists in the module (notice the capitalization): `main`
 
 error[E0432]: unresolved import `test`
   --> $DIR/inaccessible-test-modules.rs:6:5
@@ -14,7 +14,7 @@ LL | use test as y;
    |     ----^^^^^
    |     |
    |     no `test` in the root
-   |     help: a similar name exists in the module: `test`
+   |     help: a similar name exists in the module (notice the capitalization): `test`
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/traits/trait-impl-for-module.stderr b/src/test/ui/traits/trait-impl-for-module.stderr
index 4a06cd777d4..8b81192aa47 100644
--- a/src/test/ui/traits/trait-impl-for-module.stderr
+++ b/src/test/ui/traits/trait-impl-for-module.stderr
@@ -2,7 +2,7 @@ error[E0573]: expected type, found module `a`
   --> $DIR/trait-impl-for-module.rs:7:12
    |
 LL | impl A for a {
-   |            ^ help: a trait with a similar name exists: `A`
+   |            ^ help: a trait with a similar name exists (notice the capitalization): `A`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/utf8_idents.stderr b/src/test/ui/utf8_idents.stderr
index 56de63da4f9..869bed61ea0 100644
--- a/src/test/ui/utf8_idents.stderr
+++ b/src/test/ui/utf8_idents.stderr
@@ -38,7 +38,7 @@ warning: type parameter `γ` should have an upper camel case name
   --> $DIR/utf8_idents.rs:3:5
    |
 LL |     γ
-   |     ^ help: convert the identifier to upper camel case: `Γ`
+   |     ^ help: convert the identifier to upper camel case (notice the capitalization): `Γ`
    |
    = note: `#[warn(non_camel_case_types)]` on by default