[Go] Improve generic type support (#4041)

Addresses some issues described in #3512 with least effort.

It may not address all theoretical edge cases though.

Especially meta scopes don't follow guidelines by any means, so seriously
fixing issues would probably end up in significant refactoring, which is not
scope of this commit/PR.

Go/Go.sublime-syntax

@@ -84,6 +84,9 @@ variables:
 
   keyword_or_ident: \b[[:alpha:]_][[:alnum:]_]*\b
 
+  # Heuristic to scope types, assuming they start with upper case
+  type_ident: \b[[:upper:]_][[:alnum:]_]*\b
+
   # Sublime normalizes newlines from `\r\n` and `\r` into `\n`. Sublime's syntax
   # engine uses regexps line-by-line, so `$` is often equivalent to `\n`. For
   # semantic accuracy, we should use `\n` when possible. However, the last line
@@ -122,8 +125,33 @@ variables:
   #
   # Known defect: fails to recognize multiline type argument lists.
   # We should convert from lookahead to branching.
-  type_argument_list: \[(?:{{noise}}|[^\[\]])*\]
-
+  type_argument_list: |-
+    (?x:
+      \[ (?:
+      {{noise}}
+      | \[ (?:
+        {{noise}}
+        | \[ (?:
+          {{noise}}
+          | \[ (?:
+            {{noise}}
+            | \[ (?:
+              {{noise}}
+              | \[ (?:
+                {{noise}}
+                | [^\[\]]
+                )* \]
+              | [^\[\]]
+              )* \]
+            | [^\[\]]
+            )* \]
+          | [^\[\]]
+          )* \]
+        | [^\[\]]
+        )* \]
+      | [^\[\]]
+      )* \]
+    )
 
   iface_entry_delim: (?://|;|\}|{{newline}})
   struct_entry_delim: (?:"|`|{{iface_entry_delim}})
@@ -490,7 +518,7 @@ contexts:
     - match: '{{ident_anon}}(?!{{noise}}\()'
       scope: variable.language.anonymous.go
       pop: 1
-    - match: '{{ident}}(?!{{noise}}\()'
+    - match: '{{ident}}(?!{{noise}}{{type_argument_list}}?\()'
       scope: variable.other.member.go
       pop: 1
     - match: \(
@@ -1267,6 +1295,10 @@ contexts:
       scope: variable.language.anonymous.go
       push: pop-parameter-type
 
+    - match: '{{type_ident}}'
+      scope: storage.type.go
+      push: pop-type-argument-list
+
     - match: '{{ident}}'
       scope: variable.parameter.go
       push: pop-parameter-type

Go/tests/syntax_test_go.go

@@ -1211,6 +1211,16 @@ by accident, but if necessary, such support could be sacrificed.
 //                               ^^^ meta.type.go storage.type.go
 //                                  ^ meta.type.go punctuation.section.parens.end.go
 
+        Method(Type[TypeArg])
+//      ^^^^^^^^^^^^^^^^^^^^^ meta.type.go
+//      ^^^^^^ entity.name.function.go
+//            ^ punctuation.section.parens.begin.go
+//             ^^^^ storage.type.go
+//                 ^ punctuation.section.brackets.begin.go
+//                  ^^^^^^^ variable.other.type.go
+//                         ^ punctuation.section.brackets.end.go
+//                          ^ punctuation.section.parens.end.go
+
         Inherit
 //      ^^^^^^^ meta.type.go storage.type.go
 
@@ -4931,6 +4941,16 @@ by accident, but if necessary, such support could be sacrificed.
 //  ^^^^ variable.function.go
     )
 
+    ident[Type[TypeArg]]()
+//  ^^^^^ variable.function.go
+//       ^ punctuation.section.brackets.begin.go
+//        ^^^^ variable.other.type.go
+//            ^ punctuation.section.brackets.begin.go
+//             ^^^^^^^ variable.other.go
+//                    ^^ punctuation.section.brackets.end.go
+//                      ^ punctuation.section.parens.begin.go
+//                       ^ punctuation.section.parens.end.go
+
     ident.ident()
 //  ^^^^^ variable.other.go
 //       ^ punctuation.accessor.dot.go
@@ -4953,6 +4973,36 @@ by accident, but if necessary, such support could be sacrificed.
 //                    ^^^^^ variable.other.go
 //                         ^ punctuation.section.parens.end.go
 
+    ident.ident.ident[Type, Type](ident)
+//  ^^^^^ variable.other.go
+//       ^ punctuation.accessor.dot.go
+//        ^^^^^ variable.other.member.go
+//             ^ punctuation.accessor.dot.go
+//              ^^^^^ variable.function.go
+//                   ^ punctuation.section.brackets.begin.go
+//                    ^^^^ variable.other.type.go
+//                        ^ punctuation.separator.go
+//                          ^^^^ variable.other.type.go
+//                              ^ punctuation.section.brackets.end.go
+//                               ^ punctuation.section.parens.begin.go
+//                                ^^^^^ variable.other.go
+//                                     ^ punctuation.section.parens.end.go
+
+    ident.ident.ident[Type[TypeArg]](ident)
+//  ^^^^^ variable.other.go
+//       ^ punctuation.accessor.dot.go
+//        ^^^^^ variable.other.member.go
+//             ^ punctuation.accessor.dot.go
+//              ^^^^^ variable.function.go
+//                   ^ punctuation.section.brackets.begin.go
+//                    ^^^^ variable.other.type.go
+//                        ^ punctuation.section.brackets.begin.go
+//                         ^^^^^^^ variable.other.go
+//                                ^^ punctuation.section.brackets.end.go
+//                                  ^ punctuation.section.parens.begin.go
+//                                   ^^^^^ variable.other.go
+//                                        ^ punctuation.section.parens.end.go
+
     ident /**/ . /**/
 //  ^^^^^ variable.other.go
 //        ^^^^ comment.block.go
@@ -5138,6 +5188,19 @@ by accident, but if necessary, such support could be sacrificed.
     ) typ {}
 //    ^^^ storage.type.go
 
+    func FuncName(param [][]Type) {}
+//  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ meta.function.declaration.go
+//  ^^^^ keyword.declaration.function.go
+//       ^^^^^^^^ entity.name.function.go
+//               ^ punctuation.section.parens.begin.go
+//                ^^^^^ variable.parameter.go
+//                      ^ punctuation.section.brackets.begin.go
+//                       ^ punctuation.section.brackets.end.go
+//                        ^ punctuation.section.brackets.begin.go
+//                         ^ punctuation.section.brackets.end.go
+//                          ^^^^ storage.type.go
+//                              ^ punctuation.section.parens.end.go
+
 /* ### Methods */
 
     func (self Type) Method() {}
@@ -5158,6 +5221,18 @@ by accident, but if necessary, such support could be sacrificed.
 //                    ^ punctuation.section.parens.begin.go
 //                     ^ punctuation.section.parens.end.go
 
+    func(Type, Type[TypeArg])
+//  ^^^^ keyword.declaration.function.go
+//      ^^^^^^^^^^^^^^^^^^^^^ meta.function.declaration.go
+//      ^ punctuation.section.parens.begin.go
+//       ^^^^ storage.type.go
+//           ^ punctuation.separator.go
+//             ^^^^ storage.type.go
+//                 ^ punctuation.section.brackets.begin.go
+//                  ^^^^^^^ variable.other.type.go
+//                         ^ punctuation.section.brackets.end.go
+//                          ^ punctuation.section.parens.end.go
+
     func /**/
 //  ^^^^ keyword.declaration.function.go
 //       ^^^^ comment.block.go