Add backticks to various diagnostics

src/librustc/infer/error_reporting/mod.rs

@@ -661,7 +661,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
             },
             ObligationCauseCode::IfExpression(box IfExpressionCause { then, outer, semicolon }) => {
                 err.span_label(then, "expected because of this");
-                outer.map(|sp| err.span_label(sp, "if and else have incompatible types"));
+                outer.map(|sp| err.span_label(sp, "`if` and `else` have incompatible types"));
                 if let Some(sp) = semicolon {
                     err.span_suggestion_short(
                         sp,
@@ -1883,13 +1883,13 @@ impl<'tcx> ObligationCause<'tcx> {
                     hir::MatchSource::TryDesugar => {
                         "try expression alternatives have incompatible types"
                     }
-                    _ => "match arms have incompatible types",
+                    _ => "`match` arms have incompatible types",
                 })
             }
-            IfExpression { .. } => Error0308("if and else have incompatible types"),
-            IfExpressionWithNoElse => Error0317("if may be missing an else clause"),
-            MainFunctionType => Error0580("main function has wrong type"),
-            StartFunctionType => Error0308("start function has wrong type"),
+            IfExpression { .. } => Error0308("`if` and `else` have incompatible types"),
+            IfExpressionWithNoElse => Error0317("`if` may be missing an `else` clause"),
+            MainFunctionType => Error0580("`main` function has wrong type"),
+            StartFunctionType => Error0308("`#[start]` function has wrong type"),
             IntrinsicType => Error0308("intrinsic has wrong type"),
             MethodReceiver => Error0308("mismatched `self` parameter type"),
 
@@ -1917,12 +1917,12 @@ impl<'tcx> ObligationCause<'tcx> {
             ExprAssignable => "expression is assignable",
             MatchExpressionArm(box MatchExpressionArmCause { source, .. }) => match source {
                 hir::MatchSource::IfLetDesugar { .. } => "`if let` arms have compatible types",
-                _ => "match arms have compatible types",
+                _ => "`match` arms have compatible types",
             },
-            IfExpression { .. } => "if and else have incompatible types",
-            IfExpressionWithNoElse => "if missing an else returns ()",
+            IfExpression { .. } => "`if` and `else` have incompatible types",
+            IfExpressionWithNoElse => "`if` missing an `else` returns `()`",
             MainFunctionType => "`main` function has the correct type",
-            StartFunctionType => "`start` function has the correct type",
+            StartFunctionType => "`#[start]` function has the correct type",
             IntrinsicType => "intrinsic has the correct type",
             MethodReceiver => "method receiver has the correct type",
             _ => "types are compatible",

src/librustc_passes/entry.rs

@@ -134,7 +134,7 @@ fn find_item(item: &Item<'_>, ctxt: &mut EntryContext<'_, '_>, at_root: bool) {
                 ctxt.start_fn = Some((item.hir_id, item.span));
             } else {
                 struct_span_err!(ctxt.session, item.span, E0138, "multiple `start` functions")
-                    .span_label(ctxt.start_fn.unwrap().1, "previous `start` function here")
+                    .span_label(ctxt.start_fn.unwrap().1, "previous `#[start]` function here")
                     .span_label(item.span, "multiple `start` functions")
                     .emit();
             }

src/librustc_target/spec/wasm32_base.rs

@@ -81,7 +81,7 @@ pub fn options() -> TargetOptions {
         dynamic_linking: true,
         only_cdylib: true,
 
-        // This means we'll just embed a `start` function in the wasm module
+        // This means we'll just embed a `#[start]` function in the wasm module
         executables: true,
 
         // relatively self-explanatory!

src/librustc_typeck/check/_match.rs

@@ -298,7 +298,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             // LL ||         10u32
             //    ||         ^^^^^ expected `i32`, found `u32`
             // LL ||     };
-            //    ||_____- if and else have incompatible types
+            //    ||_____- `if` and `else` have incompatible types
             // ```
             Some(span)
         } else {
@@ -340,7 +340,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 // by not pointing at the entire expression:
                 // ```
                 // 2 |       let x = if true {
-                //   |               ------- if and else have incompatible types
+                //   |               ------- `if` and `else` have incompatible types
                 // 3 |           3
                 //   |           - expected because of this
                 // 4 |       } else {

src/libsyntax/feature_gate/check.rs

@@ -387,8 +387,8 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
                         &self,
                         start,
                         i.span,
-                        "a `#[start]` function is an experimental \
-                                       feature whose signature may change \
+                        "`#[start]` functions are experimental \
+                                       and their signature may change \
                                        over time"
                     );
                 }

src/test/ui/async-await/issue-66387-if-without-else.rs

@@ -1,6 +1,6 @@
 // edition:2018
 async fn f() -> i32 {
-    if true { //~ ERROR if may be missing an else clause
+    if true { //~ ERROR `if` may be missing an `else` clause
         return 0;
     }
     // An `if` block without `else` causes the type table not to have a type for this expr.

src/test/ui/async-await/issue-66387-if-without-else.stderr

@@ -1,4 +1,4 @@
-error[E0317]: if may be missing an else clause
+error[E0317]: `if` may be missing an `else` clause
   --> $DIR/issue-66387-if-without-else.rs:3:5
    |
 LL | /     if true {

src/test/ui/bad/bad-expr-path.rs

@@ -1,6 +1,6 @@
 mod m1 {}
 
-fn main(arguments: Vec<String>) { //~ ERROR main function has wrong type
+fn main(arguments: Vec<String>) { //~ ERROR `main` function has wrong type
     log(debug, m1::arguments);
     //~^ ERROR cannot find function `log` in this scope
     //~| ERROR cannot find value `debug` in this scope

src/test/ui/bad/bad-expr-path.stderr

@@ -16,7 +16,7 @@ error[E0425]: cannot find value `arguments` in module `m1`
 LL |     log(debug, m1::arguments);
    |                    ^^^^^^^^^ not found in `m1`
 
-error[E0580]: main function has wrong type
+error[E0580]: `main` function has wrong type
   --> $DIR/bad-expr-path.rs:3:1
    |
 LL | fn main(arguments: Vec<String>) {

src/test/ui/bad/bad-expr-path2.rs

@@ -2,7 +2,7 @@ mod m1 {
     pub mod arguments {}
 }
 
-fn main(arguments: Vec<String>) { //~ ERROR main function has wrong type
+fn main(arguments: Vec<String>) { //~ ERROR `main` function has wrong type
     log(debug, m1::arguments);
     //~^ ERROR cannot find function `log` in this scope
     //~| ERROR cannot find value `debug` in this scope

src/test/ui/bad/bad-expr-path2.stderr

@@ -16,7 +16,7 @@ error[E0423]: expected value, found module `m1::arguments`
 LL |     log(debug, m1::arguments);
    |                ^^^^^^^^^^^^^ not a value
 
-error[E0580]: main function has wrong type
+error[E0580]: `main` function has wrong type
   --> $DIR/bad-expr-path2.rs:5:1
    |
 LL | fn main(arguments: Vec<String>) {

src/test/ui/bad/bad-main.rs

@@ -1 +1 @@
-fn main(x: isize) { } //~ ERROR: main function has wrong type [E0580]
+fn main(x: isize) { } //~ ERROR: `main` function has wrong type [E0580]

src/test/ui/bad/bad-main.stderr

@@ -1,4 +1,4 @@
-error[E0580]: main function has wrong type
+error[E0580]: `main` function has wrong type
   --> $DIR/bad-main.rs:1:1
    |
 LL | fn main(x: isize) { }

src/test/ui/consts/control-flow/issue-50577.if_match.stderr

@@ -1,4 +1,4 @@
-error[E0317]: if may be missing an else clause
+error[E0317]: `if` may be missing an `else` clause
   --> $DIR/issue-50577.rs:7:16
    |
 LL |         Drop = assert_eq!(1, 1)

src/test/ui/consts/control-flow/issue-50577.rs

@@ -5,7 +5,7 @@
 fn main() {
     enum Foo {
         Drop = assert_eq!(1, 1)
-        //[stock,if_match]~^ ERROR if may be missing an else clause
+        //[stock,if_match]~^ ERROR `if` may be missing an `else` clause
         //[stock]~^^ ERROR `match` is not allowed in a `const`
         //[stock]~| ERROR `match` is not allowed in a `const`
         //[stock]~| ERROR `if` is not allowed in a `const`

src/test/ui/consts/control-flow/issue-50577.stock.stderr

@@ -28,7 +28,7 @@ LL |         Drop = assert_eq!(1, 1)
    = help: add `#![feature(const_if_match)]` to the crate attributes to enable
    = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
 
-error[E0317]: if may be missing an else clause
+error[E0317]: `if` may be missing an `else` clause
   --> $DIR/issue-50577.rs:7:16
    |
 LL |         Drop = assert_eq!(1, 1)

src/test/ui/error-codes/E0138.stderr

@@ -2,7 +2,7 @@ error[E0138]: multiple `start` functions
   --> $DIR/E0138.rs:7:1
    |
 LL | fn foo(argc: isize, argv: *const *const u8) -> isize { 0 }
-   | ---------------------------------------------------------- previous `start` function here
+   | ---------------------------------------------------------- previous `#[start]` function here
 ...
 LL | fn f(argc: isize, argv: *const *const u8) -> isize { 0 }
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ multiple `start` functions

src/test/ui/extern/extern-main-fn.rs

@@ -1 +1 @@
-extern fn main() {} //~ ERROR: main function has wrong type [E0580]
+extern fn main() {} //~ ERROR: `main` function has wrong type [E0580]

src/test/ui/extern/extern-main-fn.stderr

@@ -1,4 +1,4 @@
-error[E0580]: main function has wrong type
+error[E0580]: `main` function has wrong type
   --> $DIR/extern-main-fn.rs:1:1
    |
 LL | extern fn main() {}

src/test/ui/feature-gates/feature-gate-start.rs

@@ -1,3 +1,3 @@
 #[start]
 fn foo(_: isize, _: *const *const u8) -> isize { 0 }
-//~^ ERROR a `#[start]` function is an experimental feature
+//~^ ERROR `#[start]` functions are experimental

src/test/ui/feature-gates/feature-gate-start.stderr

@@ -1,4 +1,4 @@
-error[E0658]: a `#[start]` function is an experimental feature whose signature may change over time
+error[E0658]: `#[start]` functions are experimental and their signature may change over time
   --> $DIR/feature-gate-start.rs:2:1
    |
 LL | fn foo(_: isize, _: *const *const u8) -> isize { 0 }

src/test/ui/if-else-type-mismatch.rs

@@ -4,43 +4,43 @@ fn main() {
     } else {
         2u32
     };
-    //~^^ ERROR if and else have incompatible types
+    //~^^ ERROR `if` and `else` have incompatible types
     let _ = if true { 42i32 } else { 42u32 };
-    //~^ ERROR if and else have incompatible types
+    //~^ ERROR `if` and `else` have incompatible types
     let _ = if true {
         3u32;
     } else {
         4u32
     };
-    //~^^ ERROR if and else have incompatible types
+    //~^^ ERROR `if` and `else` have incompatible types
     let _ = if true {
         5u32
     } else {
         6u32;
     };
-    //~^^ ERROR if and else have incompatible types
+    //~^^ ERROR `if` and `else` have incompatible types
     let _ = if true {
         7i32;
     } else {
         8u32
     };
-    //~^^ ERROR if and else have incompatible types
+    //~^^ ERROR `if` and `else` have incompatible types
     let _ = if true {
         9i32
     } else {
         10u32;
     };
-    //~^^ ERROR if and else have incompatible types
+    //~^^ ERROR `if` and `else` have incompatible types
     let _ = if true {
 
     } else {
         11u32
     };
-    //~^^ ERROR if and else have incompatible types
+    //~^^ ERROR `if` and `else` have incompatible types
     let _ = if true {
         12i32
     } else {
 
     };
-    //~^^^ ERROR if and else have incompatible types
+    //~^^^ ERROR `if` and `else` have incompatible types
 }

src/test/ui/if-else-type-mismatch.stderr

@@ -1,4 +1,4 @@
-error[E0308]: if and else have incompatible types
+error[E0308]: `if` and `else` have incompatible types
   --> $DIR/if-else-type-mismatch.rs:5:9
    |
 LL |       let _ = if true {
@@ -9,17 +9,17 @@ LL | |     } else {
 LL | |         2u32
    | |         ^^^^ expected `i32`, found `u32`
 LL | |     };
-   | |_____- if and else have incompatible types
+   | |_____- `if` and `else` have incompatible types
 
-error[E0308]: if and else have incompatible types
+error[E0308]: `if` and `else` have incompatible types
   --> $DIR/if-else-type-mismatch.rs:8:38
    |
 LL |     let _ = if true { 42i32 } else { 42u32 };
    |                       -----          ^^^^^ expected `i32`, found `u32`
    |                       |
    |                       expected because of this
 
-error[E0308]: if and else have incompatible types
+error[E0308]: `if` and `else` have incompatible types
   --> $DIR/if-else-type-mismatch.rs:13:9
    |
 LL |       let _ = if true {
@@ -33,9 +33,9 @@ LL | |     } else {
 LL | |         4u32
    | |         ^^^^ expected `()`, found `u32`
 LL | |     };
-   | |_____- if and else have incompatible types
+   | |_____- `if` and `else` have incompatible types
 
-error[E0308]: if and else have incompatible types
+error[E0308]: `if` and `else` have incompatible types
   --> $DIR/if-else-type-mismatch.rs:19:9
    |
 LL |       let _ = if true {
@@ -49,9 +49,9 @@ LL | |         6u32;
    | |         |   help: consider removing this semicolon
    | |         expected `u32`, found `()`
 LL | |     };
-   | |_____- if and else have incompatible types
+   | |_____- `if` and `else` have incompatible types
 
-error[E0308]: if and else have incompatible types
+error[E0308]: `if` and `else` have incompatible types
   --> $DIR/if-else-type-mismatch.rs:25:9
    |
 LL |       let _ = if true {
@@ -62,9 +62,9 @@ LL | |     } else {
 LL | |         8u32
    | |         ^^^^ expected `()`, found `u32`
 LL | |     };
-   | |_____- if and else have incompatible types
+   | |_____- `if` and `else` have incompatible types
 
-error[E0308]: if and else have incompatible types
+error[E0308]: `if` and `else` have incompatible types
   --> $DIR/if-else-type-mismatch.rs:31:9
    |
 LL |       let _ = if true {
@@ -75,9 +75,9 @@ LL | |     } else {
 LL | |         10u32;
    | |         ^^^^^^ expected `i32`, found `()`
 LL | |     };
-   | |_____- if and else have incompatible types
+   | |_____- `if` and `else` have incompatible types
 
-error[E0308]: if and else have incompatible types
+error[E0308]: `if` and `else` have incompatible types
   --> $DIR/if-else-type-mismatch.rs:37:9
    |
 LL |       let _ = if true {
@@ -88,11 +88,11 @@ LL | |     } else {
 LL |           11u32
    |           ^^^^^ expected `()`, found `u32`
 
-error[E0308]: if and else have incompatible types
+error[E0308]: `if` and `else` have incompatible types
   --> $DIR/if-else-type-mismatch.rs:42:12
    |
 LL |       let _ = if true {
-   |               ------- if and else have incompatible types
+   |               ------- `if` and `else` have incompatible types
 LL |           12i32
    |           ----- expected because of this
 LL |       } else {

src/test/ui/if/if-branch-types.rs

@@ -1,5 +1,5 @@
 fn main() {
     let x = if true { 10i32 } else { 10u32 };
-    //~^ ERROR if and else have incompatible types
+    //~^ ERROR `if` and `else` have incompatible types
     //~| expected `i32`, found `u32`
 }

src/test/ui/if/if-branch-types.stderr

@@ -1,4 +1,4 @@
-error[E0308]: if and else have incompatible types
+error[E0308]: `if` and `else` have incompatible types
   --> $DIR/if-branch-types.rs:2:38
    |
 LL |     let x = if true { 10i32 } else { 10u32 };

src/test/ui/if/if-let-arm-types.rs

@@ -1,11 +1,11 @@
 fn main() {
     if let Some(b) = None {
-        //~^ NOTE if and else have incompatible types
+        //~^ NOTE `if` and `else` have incompatible types
         ()
         //~^ NOTE expected because of this
     } else {
         1
     };
-    //~^^ ERROR: if and else have incompatible types
+    //~^^ ERROR: `if` and `else` have incompatible types
     //~| NOTE expected `()`, found integer
 }

src/test/ui/if/if-let-arm-types.stderr

@@ -1,4 +1,4 @@
-error[E0308]: if and else have incompatible types
+error[E0308]: `if` and `else` have incompatible types
   --> $DIR/if-let-arm-types.rs:7:9
    |
 LL | /     if let Some(b) = None {
@@ -10,7 +10,7 @@ LL | |     } else {
 LL | |         1
    | |         ^ expected `()`, found integer
 LL | |     };
-   | |_____- if and else have incompatible types
+   | |_____- `if` and `else` have incompatible types
 
 error: aborting due to previous error