Allow attributes before function arguments

This adds support for function calls of the form:

```rust
  (
    #[attr(...)] 1.2,
    #[attr_one(...)]
    #[attr_two(...)]
    1.5,
    ... etc ...
  )
```

Closes https://github.com/rust-analyzer/rust-analyzer/issues/2801

3 files changed, 126 insertions, 0 deletions

diff --git a/crates/ra_parser/src/grammar/expressions.rs b/crates/ra_parser/src/grammar/expressions.rs
index 81d4f75f9..7caed66a0 100644
--- a/crates/ra_parser/src/grammar/expressions.rs
+++ b/crates/ra_parser/src/grammar/expressions.rs
@@ -535,11 +535,22 @@ fn cast_expr(p: &mut Parser, lhs: CompletedMarker) -> CompletedMarker {
     m.complete(p, CAST_EXPR)
 }
 
+// test arg_list
+// fn assert_float(s: &str, n: f64) {}
+// fn foo() {
+//     assert_float(
+//         "1.797693134862315708e+308L",
+//         #[allow(clippy::excessive_precision)]
+//         #[allow(dead_code)]
+//         1.797_693_134_862_315_730_8e+308,
+//     );
+// }
 fn arg_list(p: &mut Parser) {
     assert!(p.at(T!['(']));
     let m = p.start();
     p.bump(T!['(']);
     while !p.at(T![')']) && !p.at(EOF) {
+        attributes::outer_attributes(p);
         if !p.at_ts(EXPR_FIRST) {
             p.error("expected expression");
             break;
diff --git a/crates/ra_syntax/test_data/parser/inline/ok/0152_arg_list.rs b/crates/ra_syntax/test_data/parser/inline/ok/0152_arg_list.rs
new file mode 100644
index 000000000..a4009b392
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/inline/ok/0152_arg_list.rs
@@ -0,0 +1,9 @@
+fn assert_float(s: &str, n: f64) {}
+fn foo() {
+    assert_float(
+        "1.797693134862315708e+308L",
+        #[allow(clippy::excessive_precision)]
+        #[allow(dead_code)]
+        1.797_693_134_862_315_730_8e+308,
+    );
+}
diff --git a/crates/ra_syntax/test_data/parser/inline/ok/0152_arg_list.txt b/crates/ra_syntax/test_data/parser/inline/ok/0152_arg_list.txt
new file mode 100644
index 000000000..6b1992dac
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/inline/ok/0152_arg_list.txt
@@ -0,0 +1,106 @@
+SOURCE_FILE@[0; 228)
+  FN_DEF@[0; 35)
+    FN_KW@[0; 2) "fn"
+    WHITESPACE@[2; 3) " "
+    NAME@[3; 15)
+      IDENT@[3; 15) "assert_float"
+    PARAM_LIST@[15; 32)
+      L_PAREN@[15; 16) "("
+      PARAM@[16; 23)
+        BIND_PAT@[16; 17)
+          NAME@[16; 17)
+            IDENT@[16; 17) "s"
+        COLON@[17; 18) ":"
+        WHITESPACE@[18; 19) " "
+        REFERENCE_TYPE@[19; 23)
+          AMP@[19; 20) "&"
+          PATH_TYPE@[20; 23)
+            PATH@[20; 23)
+              PATH_SEGMENT@[20; 23)
+                NAME_REF@[20; 23)
+                  IDENT@[20; 23) "str"
+      COMMA@[23; 24) ","
+      WHITESPACE@[24; 25) " "
+      PARAM@[25; 31)
+        BIND_PAT@[25; 26)
+          NAME@[25; 26)
+            IDENT@[25; 26) "n"
+        COLON@[26; 27) ":"
+        WHITESPACE@[27; 28) " "
+        PATH_TYPE@[28; 31)
+          PATH@[28; 31)
+            PATH_SEGMENT@[28; 31)
+              NAME_REF@[28; 31)
+                IDENT@[28; 31) "f64"
+      R_PAREN@[31; 32) ")"
+    WHITESPACE@[32; 33) " "
+    BLOCK_EXPR@[33; 35)
+      BLOCK@[33; 35)
+        L_CURLY@[33; 34) "{"
+        R_CURLY@[34; 35) "}"
+  WHITESPACE@[35; 36) "\n"
+  FN_DEF@[36; 227)
+    FN_KW@[36; 38) "fn"
+    WHITESPACE@[38; 39) " "
+    NAME@[39; 42)
+      IDENT@[39; 42) "foo"
+    PARAM_LIST@[42; 44)
+      L_PAREN@[42; 43) "("
+      R_PAREN@[43; 44) ")"
+    WHITESPACE@[44; 45) " "
+    BLOCK_EXPR@[45; 227)
+      BLOCK@[45; 227)
+        L_CURLY@[45; 46) "{"
+        WHITESPACE@[46; 51) "\n    "
+        EXPR_STMT@[51; 225)
+          CALL_EXPR@[51; 224)
+            PATH_EXPR@[51; 63)
+              PATH@[51; 63)
+                PATH_SEGMENT@[51; 63)
+                  NAME_REF@[51; 63)
+                    IDENT@[51; 63) "assert_float"
+            ARG_LIST@[63; 224)
+              L_PAREN@[63; 64) "("
+              WHITESPACE@[64; 73) "\n        "
+              LITERAL@[73; 101)
+                STRING@[73; 101) "\"1.797693134862315708 ..."
+              COMMA@[101; 102) ","
+              WHITESPACE@[102; 111) "\n        "
+              ATTR@[111; 148)
+                POUND@[111; 112) "#"
+                L_BRACK@[112; 113) "["
+                PATH@[113; 118)
+                  PATH_SEGMENT@[113; 118)
+                    NAME_REF@[113; 118)
+                      IDENT@[113; 118) "allow"
+                TOKEN_TREE@[118; 147)
+                  L_PAREN@[118; 119) "("
+                  IDENT@[119; 125) "clippy"
+                  COLON@[125; 126) ":"
+                  COLON@[126; 127) ":"
+                  IDENT@[127; 146) "excessive_precision"
+                  R_PAREN@[146; 147) ")"
+                R_BRACK@[147; 148) "]"
+              WHITESPACE@[148; 157) "\n        "
+              ATTR@[157; 176)
+                POUND@[157; 158) "#"
+                L_BRACK@[158; 159) "["
+                PATH@[159; 164)
+                  PATH_SEGMENT@[159; 164)
+                    NAME_REF@[159; 164)
+                      IDENT@[159; 164) "allow"
+                TOKEN_TREE@[164; 175)
+                  L_PAREN@[164; 165) "("
+                  IDENT@[165; 174) "dead_code"
+                  R_PAREN@[174; 175) ")"
+                R_BRACK@[175; 176) "]"
+              WHITESPACE@[176; 185) "\n        "
+              LITERAL@[185; 217)
+                FLOAT_NUMBER@[185; 217) "1.797_693_134_862_315 ..."
+              COMMA@[217; 218) ","
+              WHITESPACE@[218; 223) "\n    "
+              R_PAREN@[223; 224) ")"
+          SEMI@[224; 225) ";"
+        WHITESPACE@[225; 226) "\n"
+        R_CURLY@[226; 227) "}"
+  WHITESPACE@[227; 228) "\n"