From 799d2917e7bb36c95224436a39cd2d468f93f45d Mon Sep 17 00:00:00 2001
From: yukang <moorekang@gmail.com>
Date: Mon, 3 Jul 2023 23:54:49 +0800
Subject: [PATCH] Detect extra space in keyword for better hint

---
 .../rustc_parse/src/parser/diagnostics.rs     |  16 ++++++++++++++++
 tests/ui/parser/utf16-be-without-bom.stderr   | Bin 3537 -> 3641 bytes
 tests/ui/parser/utf16-le-without-bom.stderr   | Bin 3500 -> 3603 bytes
 tests/ui/suggestions/issue-89640.rs           |   3 +++
 tests/ui/suggestions/issue-89640.stderr       |  13 +++++++++++++
 5 files changed, 32 insertions(+)
 create mode 100644 tests/ui/suggestions/issue-89640.rs
 create mode 100644 tests/ui/suggestions/issue-89640.stderr

diff --git a/compiler/rustc_parse/src/parser/diagnostics.rs b/compiler/rustc_parse/src/parser/diagnostics.rs
index 228eff1269f11..0ce6a570d258d 100644
--- a/compiler/rustc_parse/src/parser/diagnostics.rs
+++ b/compiler/rustc_parse/src/parser/diagnostics.rs
@@ -605,6 +605,22 @@ impl<'a> Parser<'a> {
             }
         }
 
+        if let TokenKind::Ident(prev, _) = &self.prev_token.kind
+          && let TokenKind::Ident(cur, _) = &self.token.kind
+        {
+                let concat = Symbol::intern(&format!("{}{}", prev, cur));
+                let ident = Ident::new(concat, DUMMY_SP);
+                if ident.is_used_keyword() || ident.is_reserved() || ident.is_raw_guess() {
+                    let span = self.prev_token.span.to(self.token.span);
+                    err.span_suggestion_verbose(
+                        span,
+                        format!("consider removing the space to spell keyword `{}`", concat),
+                        concat,
+                        Applicability::MachineApplicable,
+                    );
+                }
+        }
+
         // `pub` may be used for an item or `pub(crate)`
         if self.prev_token.is_ident_named(sym::public)
             && (self.token.can_begin_item()
diff --git a/tests/ui/parser/utf16-be-without-bom.stderr b/tests/ui/parser/utf16-be-without-bom.stderr
index 768d2c531641732c05cff6bd77f1662976f9f6e0..c041f3ecf53b22d8bfd994f7a8c24d583594e027 100644
GIT binary patch
delta 92
zcmca8y;EkxQeIC51%(=}jMSV0D~06zyyDE1)FOqV)ZF~C%)E4kl8jV^;)2BFRE3g!
rAR{#=M<F}4vOK>iMIj+AFM$iJ*~dqrMu8!1asZbMQ(fKUCA_)-=}{j4

delta 11
Scmdlfb5VN3Qr^kDd^!Le@dN$<

diff --git a/tests/ui/parser/utf16-le-without-bom.stderr b/tests/ui/parser/utf16-le-without-bom.stderr
index 4f4b91e39ed8779be5e03134b51ade7a8154ff05..cc2220441ac1073c755b178c4da74085faedd2a1 100644
GIT binary patch
delta 91
zcmZ1@Jy~W$1FwgIf<g^fMruxhl|piUUU6nhYLP-wYHog6W?s5NNk*zdaY15oszOOV
qkdc~`qmZ3iS)N~%qL7f5m%s(q?Bk<QqmVW^fJ=s{u5NNYuPy+lq8@1g

delta 11
ScmbO%vqpMD1MlSLygC3IumooS

diff --git a/tests/ui/suggestions/issue-89640.rs b/tests/ui/suggestions/issue-89640.rs
new file mode 100644
index 0000000000000..6bb33ad8f302c
--- /dev/null
+++ b/tests/ui/suggestions/issue-89640.rs
@@ -0,0 +1,3 @@
+fn main() {
+    le t x: i32 = 3; //~ ERROR expected one of
+}
diff --git a/tests/ui/suggestions/issue-89640.stderr b/tests/ui/suggestions/issue-89640.stderr
new file mode 100644
index 0000000000000..8ff4ef4f0ecf0
--- /dev/null
+++ b/tests/ui/suggestions/issue-89640.stderr
@@ -0,0 +1,13 @@
+error: expected one of `!`, `.`, `::`, `;`, `?`, `{`, `}`, or an operator, found `t`
+  --> $DIR/issue-89640.rs:2:8
+   |
+LL |     le t x: i32 = 3;
+   |        ^ expected one of 8 possible tokens
+   |
+help: consider removing the space to spell keyword `let`
+   |
+LL |     let x: i32 = 3;
+   |     ~~~
+
+error: aborting due to previous error
+