Merge #1393

1393: fix: support existential type r=matklad a=csmoe

Closes https://github.com/rust-analyzer/rust-analyzer/issues/1387
r? @matklad 

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

4 files changed, 35 insertions, 3 deletions

diff --git a/crates/ra_syntax/tests/data/parser/err/0011_extern_struct.txt b/crates/ra_syntax/tests/data/parser/err/0011_extern_struct.txt
index 033dac2aa..381147dc0 100644
--- a/crates/ra_syntax/tests/data/parser/err/0011_extern_struct.txt
+++ b/crates/ra_syntax/tests/data/parser/err/0011_extern_struct.txt
@@ -10,4 +10,4 @@ SOURCE_FILE@[0; 19)
       IDENT@[14; 17) "Foo"
     SEMI@[17; 18) ";"
   WHITESPACE@[18; 19) "\n"
-error 6: expected fn, trait or impl
+error 6: expected existential, fn, trait or impl
diff --git a/crates/ra_syntax/tests/data/parser/inline/err/0010_wrong_order_fns.txt b/crates/ra_syntax/tests/data/parser/inline/err/0010_wrong_order_fns.txt
index 9eb4c9b36..b1ef210d3 100644
--- a/crates/ra_syntax/tests/data/parser/inline/err/0010_wrong_order_fns.txt
+++ b/crates/ra_syntax/tests/data/parser/inline/err/0010_wrong_order_fns.txt
@@ -35,5 +35,5 @@ SOURCE_FILE@[0; 50)
       L_CURLY@[47; 48) "{"
       R_CURLY@[48; 49) "}"
   WHITESPACE@[49; 50) "\n"
-error 5: expected fn, trait or impl
-error 31: expected fn, trait or impl
+error 5: expected existential, fn, trait or impl
+error 31: expected existential, fn, trait or impl
diff --git a/crates/ra_syntax/tests/data/parser/inline/ok/0131_existential_type.rs b/crates/ra_syntax/tests/data/parser/inline/ok/0131_existential_type.rs
new file mode 100644
index 000000000..23baf7145
--- /dev/null
+++ b/crates/ra_syntax/tests/data/parser/inline/ok/0131_existential_type.rs
@@ -0,0 +1 @@
+existential type Foo: Fn() -> usize;
diff --git a/crates/ra_syntax/tests/data/parser/inline/ok/0131_existential_type.txt b/crates/ra_syntax/tests/data/parser/inline/ok/0131_existential_type.txt
new file mode 100644
index 000000000..6bfac985a
--- /dev/null
+++ b/crates/ra_syntax/tests/data/parser/inline/ok/0131_existential_type.txt
@@ -0,0 +1,31 @@
+SOURCE_FILE@[0; 37)
+  TYPE_ALIAS_DEF@[0; 36)
+    EXISTENTIAL_KW@[0; 11) "existential"
+    WHITESPACE@[11; 12) " "
+    TYPE_KW@[12; 16) "type"
+    WHITESPACE@[16; 17) " "
+    NAME@[17; 20)
+      IDENT@[17; 20) "Foo"
+    COLON@[20; 21) ":"
+    WHITESPACE@[21; 22) " "
+    TYPE_BOUND_LIST@[22; 35)
+      TYPE_BOUND@[22; 35)
+        PATH_TYPE@[22; 35)
+          PATH@[22; 35)
+            PATH_SEGMENT@[22; 35)
+              NAME_REF@[22; 24)
+                IDENT@[22; 24) "Fn"
+              PARAM_LIST@[24; 26)
+                L_PAREN@[24; 25) "("
+                R_PAREN@[25; 26) ")"
+              WHITESPACE@[26; 27) " "
+              RET_TYPE@[27; 35)
+                THIN_ARROW@[27; 29) "->"
+                WHITESPACE@[29; 30) " "
+                PATH_TYPE@[30; 35)
+                  PATH@[30; 35)
+                    PATH_SEGMENT@[30; 35)
+                      NAME_REF@[30; 35)
+                        IDENT@[30; 35) "usize"
+    SEMI@[35; 36) ";"
+  WHITESPACE@[36; 37) "\n"