From 197e7841401a3daec02cfddd0282eafc223a7c64 Mon Sep 17 00:00:00 2001
From: Jon Ross-Perkins <jperkins@google.com>
Date: Mon, 24 Feb 2025 18:07:10 -0800
Subject: [PATCH] Add parsing for partial types (#5009)

---
 toolchain/check/handle_operator.cpp            |  5 +++++
 toolchain/parse/node_kind.def                  |  1 +
 toolchain/parse/precedence.cpp                 |  2 ++
 .../parse/testdata/operators/prefix.carbon     | 18 ++++++++++++++++++
 4 files changed, 26 insertions(+)

diff --git a/toolchain/check/handle_operator.cpp b/toolchain/check/handle_operator.cpp
index 403fbc3ab750..ada2c8c88293 100644
--- a/toolchain/check/handle_operator.cpp
+++ b/toolchain/check/handle_operator.cpp
@@ -300,6 +300,11 @@ auto HandleParseNode(Context& context, Parse::PrefixOperatorNotId node_id)
   return true;
 }
 
+auto HandleParseNode(Context& context, Parse::PrefixOperatorPartialId node_id)
+    -> bool {
+  return context.TODO(node_id, "partial operator");
+}
+
 auto HandleParseNode(Context& context, Parse::PrefixOperatorPlusPlusId node_id)
     -> bool {
   return HandleUnaryOperator(context, node_id, {"Inc"});
diff --git a/toolchain/parse/node_kind.def b/toolchain/parse/node_kind.def
index 1ff2fc68d40c..bf54e99969a2 100644
--- a/toolchain/parse/node_kind.def
+++ b/toolchain/parse/node_kind.def
@@ -244,6 +244,7 @@ CARBON_PARSE_NODE_KIND_PREFIX_OPERATOR(Const)
 CARBON_PARSE_NODE_KIND_PREFIX_OPERATOR(Not)
 CARBON_PARSE_NODE_KIND_PREFIX_OPERATOR(Minus)
 CARBON_PARSE_NODE_KIND_PREFIX_OPERATOR(MinusMinus)
+CARBON_PARSE_NODE_KIND_PREFIX_OPERATOR(Partial)
 CARBON_PARSE_NODE_KIND_PREFIX_OPERATOR(PlusPlus)
 CARBON_PARSE_NODE_KIND_PREFIX_OPERATOR(Star)
 
diff --git a/toolchain/parse/precedence.cpp b/toolchain/parse/precedence.cpp
index c81f0155d75d..7500232a5835 100644
--- a/toolchain/parse/precedence.cpp
+++ b/toolchain/parse/precedence.cpp
@@ -164,6 +164,7 @@ auto PrecedenceGroup::ForLeading(Lex::TokenKind kind)
       return PrecedenceGroup(If);
 
     case Lex::TokenKind::Const:
+    case Lex::TokenKind::Partial:
       return PrecedenceGroup(TypePrefix);
 
     default:
@@ -243,6 +244,7 @@ auto PrecedenceGroup::ForTrailing(Lex::TokenKind kind, bool infix)
     case Lex::TokenKind::Const:
     case Lex::TokenKind::MinusMinus:
     case Lex::TokenKind::Not:
+    case Lex::TokenKind::Partial:
     case Lex::TokenKind::PlusPlus:
       break;
 
diff --git a/toolchain/parse/testdata/operators/prefix.carbon b/toolchain/parse/testdata/operators/prefix.carbon
index 29d1f295ba74..f3d372ba0646 100644
--- a/toolchain/parse/testdata/operators/prefix.carbon
+++ b/toolchain/parse/testdata/operators/prefix.carbon
@@ -11,6 +11,9 @@
 var n: i8 = -n;
 var b: bool = not true;
 
+var c: const bool;
+var d: partial C*;
+
 // CHECK:STDOUT: - filename: prefix.carbon
 // CHECK:STDOUT:   parse_tree: [
 // CHECK:STDOUT:     {kind: 'FileStart', text: ''},
@@ -32,5 +35,20 @@ var b: bool = not true;
 // CHECK:STDOUT:         {kind: 'BoolLiteralTrue', text: 'true'},
 // CHECK:STDOUT:       {kind: 'PrefixOperatorNot', text: 'not', subtree_size: 2},
 // CHECK:STDOUT:     {kind: 'VariableDecl', text: ';', subtree_size: 9},
+// CHECK:STDOUT:       {kind: 'VariableIntroducer', text: 'var'},
+// CHECK:STDOUT:           {kind: 'IdentifierNameNotBeforeParams', text: 'c'},
+// CHECK:STDOUT:             {kind: 'BoolTypeLiteral', text: 'bool'},
+// CHECK:STDOUT:           {kind: 'PrefixOperatorConst', text: 'const', subtree_size: 2},
+// CHECK:STDOUT:         {kind: 'VarBindingPattern', text: ':', subtree_size: 4},
+// CHECK:STDOUT:       {kind: 'VariablePattern', text: 'var', subtree_size: 5},
+// CHECK:STDOUT:     {kind: 'VariableDecl', text: ';', subtree_size: 7},
+// CHECK:STDOUT:       {kind: 'VariableIntroducer', text: 'var'},
+// CHECK:STDOUT:           {kind: 'IdentifierNameNotBeforeParams', text: 'd'},
+// CHECK:STDOUT:               {kind: 'IdentifierNameExpr', text: 'C'},
+// CHECK:STDOUT:             {kind: 'PrefixOperatorPartial', text: 'partial', subtree_size: 2},
+// CHECK:STDOUT:           {kind: 'PostfixOperatorStar', text: '*', subtree_size: 3},
+// CHECK:STDOUT:         {kind: 'VarBindingPattern', text: ':', subtree_size: 5},
+// CHECK:STDOUT:       {kind: 'VariablePattern', text: 'var', subtree_size: 6},
+// CHECK:STDOUT:     {kind: 'VariableDecl', text: ';', subtree_size: 8},
 // CHECK:STDOUT:     {kind: 'FileEnd', text: ''},
 // CHECK:STDOUT:   ]