[clangd] Added special HighlightingKind for function parameters.

[jvikstrom]

Summary

This means that function parameters are no longer highlighted as variable.other.cpp but instead as variable.parameter.cpp which is the more "correct" TextMate scope for them.

[ilya-biryukov]

LGTM

clang-tools-extra/clangd/SemanticHighlighting.h

 #include "ClangdUnit.h"
 #include "Protocol.h"
 
 namespace clang {
 namespace clangd {
 
 enum class HighlightingKind {
   Variable = 0,
+  Parameter,
   Function,
   Method,
   Field,
   Class,
   Enum,
   EnumConstant,
   Namespace,
   TemplateParameter,

clang-tools-extra/clangd/SemanticHighlighting.cpp

 //===--- SemanticHighlighting.cpp - ------------------------- ---*- C++ -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #include "SemanticHighlighting.h"
 #include "Logger.h"
 #include "Protocol.h"
 #include "SourceCode.h"
 #include "clang/AST/ASTContext.h"
+#include "clang/AST/Decl.h"
 #include "clang/AST/DeclCXX.h"
 #include "clang/AST/RecursiveASTVisitor.h"
 #include <algorithm>
 
 namespace clang {
 namespace clangd {
 namespace {
 
void addToken(SourceLocation Loc, const NamedDecl *D) {
     if (isa<EnumDecl>(D)) {
       addToken(Loc, HighlightingKind::Enum);
       return;
     }
     if (isa<EnumConstantDecl>(D)) {
       addToken(Loc, HighlightingKind::EnumConstant);
       return;
     }
+    if (isa<ParmVarDecl>(D)) {
+      addToken(Loc, HighlightingKind::Parameter);
+      return;
+    }
     if (isa<VarDecl>(D)) {
       addToken(Loc, HighlightingKind::Variable);
       return;
     }
     if (isa<FunctionDecl>(D)) {
       addToken(Loc, HighlightingKind::Function);
       return;
     }
llvm::StringRef toTextMateScope(HighlightingKind Kind) {
   // FIXME: Add scopes for C and Objective C.
   switch (Kind) {
   case HighlightingKind::Function:
     return "entity.name.function.cpp";
   case HighlightingKind::Method:
     return "entity.name.function.method.cpp";
   case HighlightingKind::Variable:
     return "variable.other.cpp";
+  case HighlightingKind::Parameter:
+    return "variable.parameter.cpp";
   case HighlightingKind::Field:
     return "variable.other.field.cpp";
   case HighlightingKind::Class:
     return "entity.name.type.class.cpp";
   case HighlightingKind::Enum:
     return "entity.name.type.enum.cpp";
   case HighlightingKind::EnumConstant:
     return "variable.other.enummember.cpp";

clang-tools-extra/clangd/test/semantic-highlighting.test

 # RUN: clangd -lit-test < %s | FileCheck -strict-whitespace %s
 {"jsonrpc":"2.0","id":0,"method":"initialize","params":{"processId":123,"rootPath":"clangd","capabilities":{"textDocument":{"semanticHighlightingCapabilities":{"semanticHighlighting":true}}},"trace":"off"}}
 ---
 #      CHECK:  "id": 0,
 # CHECK:      "semanticHighlighting": {
 # CHECK-NEXT:        "scopes": [
 # CHECK-NEXT:          [
 # CHECK-NEXT:            "variable.other.cpp"
 # CHECK-NEXT:          ],
 # CHECK-NEXT:          [
+# CHECK-NEXT:            "variable.parameter.cpp"
+# CHECK-NEXT:          ],
+# CHECK-NEXT:          [
 # CHECK-NEXT:            "entity.name.function.cpp"
 # CHECK-NEXT:          ],
 # CHECK-NEXT:          [
 # CHECK-NEXT:            "entity.name.function.method.cpp"
 # CHECK-NEXT:          ],
 # CHECK-NEXT:          [
 # CHECK-NEXT:            "variable.other.field.cpp"
 # CHECK-NEXT:          ],

 # CHECK-NEXT:      },
 ---
 {"jsonrpc":"2.0","method":"textDocument/didOpen","params":{"textDocument":{"uri":"test:///foo.cpp","languageId":"cpp","version":1,"text":"int x = 2;"}}}
 #      CHECK:  "method": "textDocument/semanticHighlighting",
 # CHECK-NEXT:  "params": {
 # CHECK-NEXT:    "lines": [
 # CHECK-NEXT:      {
 # CHECK-NEXT:        "line": 0,
-# CHECK-NEXT:        "tokens": "AAAAAAADAAkAAAAEAAEAAA=="
+# CHECK-NEXT:        "tokens": "AAAAAAADAAoAAAAEAAEAAA=="
 # CHECK-NEXT:      }
 # CHECK-NEXT:    ],
 # CHECK-NEXT:    "textDocument": {
 # CHECK-NEXT:      "uri": "file:///clangd-test/foo.cpp"
 # CHECK-NEXT:    }
 # CHECK-NEXT:  }
 # CHECK-NEXT:}
 ---
 {"jsonrpc":"2.0","method":"textDocument/didOpen","params":{"textDocument":{"uri":"test:///foo2.cpp","languageId":"cpp","version":1,"text":"int x = 2;\nint y = 2;"}}}
 #      CHECK:  "method": "textDocument/semanticHighlighting",
 # CHECK-NEXT:  "params": {
 # CHECK-NEXT:    "lines": [
 # CHECK-NEXT:      {
 # CHECK-NEXT:        "line": 0,
-# CHECK-NEXT:        "tokens": "AAAAAAADAAkAAAAEAAEAAA=="
+# CHECK-NEXT:        "tokens": "AAAAAAADAAoAAAAEAAEAAA=="
 # CHECK-NEXT:      }
 # CHECK-NEXT:      {
 # CHECK-NEXT:        "line": 1,
-# CHECK-NEXT:        "tokens": "AAAAAAADAAkAAAAEAAEAAA=="
+# CHECK-NEXT:        "tokens": "AAAAAAADAAoAAAAEAAEAAA=="
 # CHECK-NEXT:      }
 # CHECK-NEXT:    ],
 # CHECK-NEXT:    "textDocument": {
 # CHECK-NEXT:      "uri": "file:///clangd-test/foo2.cpp"
 # CHECK-NEXT:    }
 # CHECK-NEXT:  }
 # CHECK-NEXT:}
 ---
 {"jsonrpc":"2.0","method":"textDocument/didChange","params":{"textDocument":{"uri":"test:///foo.cpp","version":2},"contentChanges": [{"range":{"start": {"line": 0,"character": 10},"end": {"line": 0,"character": 10}},"rangeLength": 0,"text": "\nint y = 2;"}]}}
 #      CHECK:  "method": "textDocument/semanticHighlighting",
 # CHECK-NEXT:  "params": {
 # CHECK-NEXT:    "lines": [
 # CHECK-NEXT:      {
 # CHECK-NEXT:        "line": 1,
-# CHECK-NEXT:        "tokens": "AAAAAAADAAkAAAAEAAEAAA=="
+# CHECK-NEXT:        "tokens": "AAAAAAADAAoAAAAEAAEAAA=="
 # CHECK-NEXT:      }
 # CHECK-NEXT:   ],
 # CHECK-NEXT:    "textDocument": {
 # CHECK-NEXT:      "uri": "file:///clangd-test/foo.cpp"
 # CHECK-NEXT:    }
 # CHECK-NEXT:  }
 # CHECK-NEXT:}
 ---

clang-tools-extra/clangd/unittests/SemanticHighlightingTests.cpp

makeHighlightingTokens(llvm::ArrayRef<Range> Ranges, HighlightingKind Kind) {
   }
 
   return Tokens;
 }
 
 std::vector<HighlightingToken> getExpectedTokens(Annotations &Test) {
   static const std::map<HighlightingKind, std::string> KindToString{
       {HighlightingKind::Variable, "Variable"},
+      {HighlightingKind::Parameter, "Parameter"},
       {HighlightingKind::Function, "Function"},
       {HighlightingKind::Class, "Class"},
       {HighlightingKind::Enum, "Enum"},
       {HighlightingKind::Namespace, "Namespace"},
       {HighlightingKind::EnumConstant, "EnumConstant"},
       {HighlightingKind::Field, "Field"},
       {HighlightingKind::Method, "Method"},
       {HighlightingKind::TemplateParameter, "TemplateParameter"},

 TEST(SemanticHighlighting, GetsCorrectTokens) {
   const char *TestCases[] = {
     R"cpp(
       struct $Class[[AS]] {
         $Primitive[[double]] $Field[[SomeMember]];
       };
       struct {
       } $Variable[[S]];
-      $Primitive[[void]] $Function[[foo]]($Primitive[[int]] $Variable[[A]], $Class[[AS]] $Variable[[As]]) {
+      $Primitive[[void]] $Function[[foo]]($Primitive[[int]] $Parameter[[A]], $Class[[AS]] $Parameter[[As]]) {
         $Primitive[[auto]] $Variable[[VeryLongVariableName]] = 12312;
         $Class[[AS]]     $Variable[[AA]];
-        $Primitive[[auto]] $Variable[[L]] = $Variable[[AA]].$Field[[SomeMember]] + $Variable[[A]];
-        auto $Variable[[FN]] = [ $Variable[[AA]]]($Primitive[[int]] $Variable[[A]]) -> $Primitive[[void]] {};
+        $Primitive[[auto]] $Variable[[L]] = $Variable[[AA]].$Field[[SomeMember]] + $Parameter[[A]];
+        auto $Variable[[FN]] = [ $Variable[[AA]]]($Primitive[[int]] $Parameter[[A]]) -> $Primitive[[void]] {};
         $Variable[[FN]](12312);
       }
     )cpp",
     R"cpp(
       $Primitive[[void]] $Function[[foo]]($Primitive[[int]]);
       $Primitive[[void]] $Function[[Gah]]();
       $Primitive[[void]] $Function[[foo]]() {
         auto $Variable[[Bou]] = $Function[[Gah]];
R"cpp(
         $Class[[Foo]] *$Variable[[FP]] = ($Class[[Foo]]*)$Variable[[B]];
         $Primitive[[int]] $Variable[[I]] = ($Primitive[[int]])$Variable[[B]];
       }
     )cpp"
     R"cpp(
       struct $Class[[B]] {};
       struct $Class[[A]] {
         $Class[[B]] $Field[[BB]];
-        $Class[[A]] &operator=($Class[[A]] &&$Variable[[O]]);
+        $Class[[A]] &operator=($Class[[A]] &&$Parameter[[O]]);
       };
 
-      $Class[[A]] &$Class[[A]]::operator=($Class[[A]] &&$Variable[[O]]) = default;
+      $Class[[A]] &$Class[[A]]::operator=($Class[[A]] &&$Parameter[[O]]) = default;
     )cpp",
     R"cpp(
       enum $Enum[[En]] {
         $EnumConstant[[EC]],
       };
       class $Class[[Foo]] {};
       class $Class[[Bar]] {
         $Class[[Foo]] $Field[[Fo]];
         $Enum[[En]] $Field[[E]];
         $Primitive[[int]] $Field[[I]];
-        $Class[[Bar]] ($Class[[Foo]] $Variable[[F]],
-                $Enum[[En]] $Variable[[E]])
-        : $Field[[Fo]] ($Variable[[F]]), $Field[[E]] ($Variable[[E]]),
+        $Class[[Bar]] ($Class[[Foo]] $Parameter[[F]],
+                $Enum[[En]] $Parameter[[E]])
+        : $Field[[Fo]] ($Parameter[[F]]), $Field[[E]] ($Parameter[[E]]),
           $Field[[I]] (123) {}
       };
       class $Class[[Bar2]] : public $Class[[Bar]] {
         $Class[[Bar2]]() : $Class[[Bar]]($Class[[Foo]](), $EnumConstant[[EC]]) {}
       };
     )cpp",
     R"cpp(
       enum $Enum[[E]] {
std::vector<LineHighlightings> Tokens{
         {HighlightingKind::Function,
          Range{CreatePosition(3, 4), CreatePosition(3, 7)}}}},
       {1,
        {{HighlightingKind::Variable,
          Range{CreatePosition(1, 1), CreatePosition(1, 5)}}}}};
   std::vector<SemanticHighlightingInformation> ActualResults =
       toSemanticHighlightingInformation(Tokens);
   std::vector<SemanticHighlightingInformation> ExpectedResults = {
-      {3, "AAAACAAEAAAAAAAEAAMAAQ=="}, {1, "AAAAAQAEAAA="}};
+      {3, "AAAACAAEAAAAAAAEAAMAAg=="}, {1, "AAAAAQAEAAA="}};
   EXPECT_EQ(ActualResults, ExpectedResults);
 }
 
 TEST(SemanticHighlighting, HighlightingDiffer) {
   struct {
     llvm::StringRef OldCode;
     llvm::StringRef NewCode;
   } TestCases[]{{