Merge #1661

1661: Parse function parameters attributes r=matklad a=eupn

Fixes #1397. The [RFC-2565](https://github.com/rust-lang/rfcs/blob/master/text/2565-formal-function-parameter-attributes.md) specifies `#[attributes]` to function parameters:

```rust
fn foo(#[attr] a, #[unused] b, #[must_use] ...) {
    // ...
}
```

This PR adds those attributes into grammar and to the parser, extending corresponding inline tests.

Co-authored-by: Evgenii P <[email protected]>

4 files changed, 57 insertions, 0 deletions

diff --git a/crates/ra_syntax/test_data/parser/inline/ok/0138_self_param_outer_attr.rs b/crates/ra_syntax/test_data/parser/inline/ok/0138_self_param_outer_attr.rs
new file mode 100644
index 000000000..35155057a
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/inline/ok/0138_self_param_outer_attr.rs
@@ -0,0 +1 @@
+fn f(#[must_use] self) {}
diff --git a/crates/ra_syntax/test_data/parser/inline/ok/0138_self_param_outer_attr.txt b/crates/ra_syntax/test_data/parser/inline/ok/0138_self_param_outer_attr.txt
new file mode 100644
index 000000000..49b14e632
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/inline/ok/0138_self_param_outer_attr.txt
@@ -0,0 +1,23 @@
+SOURCE_FILE@[0; 26)
+  FN_DEF@[0; 25)
+    FN_KW@[0; 2) "fn"
+    WHITESPACE@[2; 3) " "
+    NAME@[3; 4)
+      IDENT@[3; 4) "f"
+    PARAM_LIST@[4; 22)
+      L_PAREN@[4; 5) "("
+      ATTR@[5; 16)
+        POUND@[5; 6) "#"
+        TOKEN_TREE@[6; 16)
+          L_BRACK@[6; 7) "["
+          IDENT@[7; 15) "must_use"
+          R_BRACK@[15; 16) "]"
+      WHITESPACE@[16; 17) " "
+      SELF_PARAM@[17; 21)
+        SELF_KW@[17; 21) "self"
+      R_PAREN@[21; 22) ")"
+    WHITESPACE@[22; 23) " "
+    BLOCK@[23; 25)
+      L_CURLY@[23; 24) "{"
+      R_CURLY@[24; 25) "}"
+  WHITESPACE@[25; 26) "\n"
diff --git a/crates/ra_syntax/test_data/parser/inline/ok/0139_param_outer_arg.rs b/crates/ra_syntax/test_data/parser/inline/ok/0139_param_outer_arg.rs
new file mode 100644
index 000000000..c238be791
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/inline/ok/0139_param_outer_arg.rs
@@ -0,0 +1 @@
+fn f(#[attr1] pat: Type) {}
diff --git a/crates/ra_syntax/test_data/parser/inline/ok/0139_param_outer_arg.txt b/crates/ra_syntax/test_data/parser/inline/ok/0139_param_outer_arg.txt
new file mode 100644
index 000000000..91c5e5f9a
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/inline/ok/0139_param_outer_arg.txt
@@ -0,0 +1,32 @@
+SOURCE_FILE@[0; 28)
+  FN_DEF@[0; 27)
+    FN_KW@[0; 2) "fn"
+    WHITESPACE@[2; 3) " "
+    NAME@[3; 4)
+      IDENT@[3; 4) "f"
+    PARAM_LIST@[4; 24)
+      L_PAREN@[4; 5) "("
+      ATTR@[5; 13)
+        POUND@[5; 6) "#"
+        TOKEN_TREE@[6; 13)
+          L_BRACK@[6; 7) "["
+          IDENT@[7; 12) "attr1"
+          R_BRACK@[12; 13) "]"
+      WHITESPACE@[13; 14) " "
+      PARAM@[14; 23)
+        BIND_PAT@[14; 17)
+          NAME@[14; 17)
+            IDENT@[14; 17) "pat"
+        COLON@[17; 18) ":"
+        WHITESPACE@[18; 19) " "
+        PATH_TYPE@[19; 23)
+          PATH@[19; 23)
+            PATH_SEGMENT@[19; 23)
+              NAME_REF@[19; 23)
+                IDENT@[19; 23) "Type"
+      R_PAREN@[23; 24) ")"
+    WHITESPACE@[24; 25) " "
+    BLOCK@[25; 27)
+      L_CURLY@[25; 26) "{"
+      R_CURLY@[26; 27) "}"
+  WHITESPACE@[27; 28) "\n"