Merge #1383

1383: fix: never type with binding r=matklad a=csmoe

Closes https://github.com/rust-analyzer/rust-analyzer/issues/1326
r? @matklad 

Co-authored-by: csmoe <[email protected]>

4 files changed, 42 insertions, 8 deletions

diff --git a/crates/ra_parser/src/grammar/expressions.rs b/crates/ra_parser/src/grammar/expressions.rs
index 99e32c4e8..795dccea1 100644
--- a/crates/ra_parser/src/grammar/expressions.rs
+++ b/crates/ra_parser/src/grammar/expressions.rs
@@ -137,12 +137,14 @@ pub(super) fn stmt(p: &mut Parser, with_semi: StmtWithSemi) {
         m.complete(p, EXPR_STMT);
     }
 
-    // test let_stmt;
+    // test let_stmt
     // fn foo() {
     //     let a;
     //     let b: i32;
     //     let c = 92;
     //     let d: i32 = 92;
+    //     let e: !;
+    //     let _: ! = {};
     // }
     fn let_stmt(p: &mut Parser, m: Marker, with_semi: StmtWithSemi) {
         assert!(p.at(T![let]));
diff --git a/crates/ra_parser/src/parser.rs b/crates/ra_parser/src/parser.rs
index 8f654f04c..8a2e253ac 100644
--- a/crates/ra_parser/src/parser.rs
+++ b/crates/ra_parser/src/parser.rs
@@ -272,7 +272,7 @@ impl<'t> Parser<'t> {
             T![=] if jn1 && la2 == T![=] => Some((T![==], 2)),
             T![=] if jn1 && la2 == T![>] => Some((T![=>], 2)),
 
-            T![!] if la2 == T![=] => Some((T![!=], 2)),
+            T![!] if jn1 && la2 == T![=] => Some((T![!=], 2)),
             T![-] if la2 == T![>] => Some((T![->], 2)),
             _ => None,
         }
diff --git a/crates/ra_syntax/tests/data/parser/inline/ok/0049_let_stmt;.rs b/crates/ra_syntax/tests/data/parser/inline/ok/0130_let_stmt.rs
index 0a9af907f..86803fe08 100644
--- a/crates/ra_syntax/tests/data/parser/inline/ok/0049_let_stmt;.rs
+++ b/crates/ra_syntax/tests/data/parser/inline/ok/0130_let_stmt.rs
@@ -3,4 +3,6 @@ fn foo() {
     let b: i32;
     let c = 92;
     let d: i32 = 92;
+    let e: !;
+    let _: ! = {};
 }
diff --git a/crates/ra_syntax/tests/data/parser/inline/ok/0049_let_stmt;.txt b/crates/ra_syntax/tests/data/parser/inline/ok/0130_let_stmt.txt
index 1f7aa3587..82c1eb009 100644
--- a/crates/ra_syntax/tests/data/parser/inline/ok/0049_let_stmt;.txt
+++ b/crates/ra_syntax/tests/data/parser/inline/ok/0130_let_stmt.txt
@@ -1,5 +1,5 @@
-SOURCE_FILE@[0; 77)
-  FN_DEF@[0; 76)
+SOURCE_FILE@[0; 110)
+  FN_DEF@[0; 109)
     FN_KW@[0; 2) "fn"
     WHITESPACE@[2; 3) " "
     NAME@[3; 6)
@@ -8,7 +8,7 @@ SOURCE_FILE@[0; 77)
       L_PAREN@[6; 7) "("
       R_PAREN@[7; 8) ")"
     WHITESPACE@[8; 9) " "
-    BLOCK@[9; 76)
+    BLOCK@[9; 109)
       L_CURLY@[9; 10) "{"
       WHITESPACE@[10; 15) "\n    "
       LET_STMT@[15; 21)
@@ -66,6 +66,36 @@ SOURCE_FILE@[0; 77)
         LITERAL@[71; 73)
           INT_NUMBER@[71; 73) "92"
         SEMI@[73; 74) ";"
-      WHITESPACE@[74; 75) "\n"
-      R_CURLY@[75; 76) "}"
-  WHITESPACE@[76; 77) "\n"
+      WHITESPACE@[74; 79) "\n    "
+      LET_STMT@[79; 88)
+        LET_KW@[79; 82) "let"
+        WHITESPACE@[82; 83) " "
+        BIND_PAT@[83; 84)
+          NAME@[83; 84)
+            IDENT@[83; 84) "e"
+        COLON@[84; 85) ":"
+        WHITESPACE@[85; 86) " "
+        NEVER_TYPE@[86; 87)
+          EXCL@[86; 87) "!"
+        SEMI@[87; 88) ";"
+      WHITESPACE@[88; 93) "\n    "
+      LET_STMT@[93; 107)
+        LET_KW@[93; 96) "let"
+        WHITESPACE@[96; 97) " "
+        PLACEHOLDER_PAT@[97; 98)
+          UNDERSCORE@[97; 98) "_"
+        COLON@[98; 99) ":"
+        WHITESPACE@[99; 100) " "
+        NEVER_TYPE@[100; 101)
+          EXCL@[100; 101) "!"
+        WHITESPACE@[101; 102) " "
+        EQ@[102; 103) "="
+        WHITESPACE@[103; 104) " "
+        BLOCK_EXPR@[104; 106)
+          BLOCK@[104; 106)
+            L_CURLY@[104; 105) "{"
+            R_CURLY@[105; 106) "}"
+        SEMI@[106; 107) ";"
+      WHITESPACE@[107; 108) "\n"
+      R_CURLY@[108; 109) "}"
+  WHITESPACE@[109; 110) "\n"