From d101327b9937f319f704d607cd9578b133b82454 Mon Sep 17 00:00:00 2001
From: Nicolas Stucki <nicolas.stucki@gmail.com>
Date: Tue, 27 Apr 2021 11:04:20 +0200
Subject: [PATCH] Support inline val references in top level splices

Fixes #12196
---
 compiler/src/dotty/tools/dotc/transform/Splicer.scala |  8 +++++++-
 tests/neg-macros/i7839.check                          |  1 +
 tests/neg/i12196.scala                                | 10 ++++++++++
 tests/neg/i12196b.scala                               | 10 ++++++++++
 tests/pos-macros/i12196/Macros_1.scala                |  8 ++++++++
 tests/pos-macros/i12196/Test_2.scala                  |  1 +
 6 files changed, 37 insertions(+), 1 deletion(-)
 create mode 100644 tests/neg/i12196.scala
 create mode 100644 tests/neg/i12196b.scala
 create mode 100644 tests/pos-macros/i12196/Macros_1.scala
 create mode 100644 tests/pos-macros/i12196/Test_2.scala

diff --git a/compiler/src/dotty/tools/dotc/transform/Splicer.scala b/compiler/src/dotty/tools/dotc/transform/Splicer.scala
index 6fb008c88889..b150414d11ee 100644
--- a/compiler/src/dotty/tools/dotc/transform/Splicer.scala
+++ b/compiler/src/dotty/tools/dotc/transform/Splicer.scala
@@ -161,7 +161,7 @@ object Splicer {
         case SeqLiteral(elems, _) =>
           elems.foreach(checkIfValidArgument)
 
-        case tree: Ident if summon[Env].contains(tree.symbol) =>
+        case tree: Ident if summon[Env].contains(tree.symbol) || tree.symbol.is(Inline, butNot = Method) =>
           // OK
 
         case _ =>
@@ -172,6 +172,7 @@ object Splicer {
               |Parameters may only be:
               | * Quoted parameters or fields
               | * Literal values of primitive types
+              | * References to `inline val`s
               |""".stripMargin, tree.srcPos)
       }
 
@@ -242,6 +243,11 @@ object Splicer {
       case Literal(Constant(value)) =>
         interpretLiteral(value)
 
+      case tree: Ident if tree.symbol.is(Inline, butNot = Method) =>
+        tree.tpe.widenTermRefExpr match
+          case ConstantType(c) => c.value.asInstanceOf[Object]
+          case _ => throw new StopInterpretation(em"${tree.symbol} could not be inlined", tree.srcPos)
+
       // TODO disallow interpreted method calls as arguments
       case Call(fn, args) =>
         if (fn.symbol.isConstructor && fn.symbol.owner.owner.is(Package))
diff --git a/tests/neg-macros/i7839.check b/tests/neg-macros/i7839.check
index 197867ab809b..3e3fc7b2c0f1 100644
--- a/tests/neg-macros/i7839.check
+++ b/tests/neg-macros/i7839.check
@@ -6,3 +6,4 @@
   |                  Parameters may only be:
   |                   * Quoted parameters or fields
   |                   * Literal values of primitive types
+  |                   * References to `inline val`s
diff --git a/tests/neg/i12196.scala b/tests/neg/i12196.scala
new file mode 100644
index 000000000000..91619ad3c387
--- /dev/null
+++ b/tests/neg/i12196.scala
@@ -0,0 +1,10 @@
+import scala.quoted.*
+
+def qqq(s: String)(using Quotes): Expr[Unit] = '{()}
+
+inline val InlineVal = "i"
+inline def InlineDef = "i"
+
+inline def withInlineVal = ${ qqq(InlineVal) }
+inline def withInlineDef = ${ qqq(InlineDef) } // error
+inline def withString    = ${ qqq("i") }
diff --git a/tests/neg/i12196b.scala b/tests/neg/i12196b.scala
new file mode 100644
index 000000000000..3bd606d9b62e
--- /dev/null
+++ b/tests/neg/i12196b.scala
@@ -0,0 +1,10 @@
+import scala.quoted.*
+
+def qqq(s: String)(using Quotes): Expr[Unit] = '{()}
+
+abstract class Foo:
+  inline val InlineVal: String
+
+val foo: Foo = ???
+
+inline def withInlineVal = ${ qqq(foo.InlineVal) } // error
diff --git a/tests/pos-macros/i12196/Macros_1.scala b/tests/pos-macros/i12196/Macros_1.scala
new file mode 100644
index 000000000000..60e1f56b0b3d
--- /dev/null
+++ b/tests/pos-macros/i12196/Macros_1.scala
@@ -0,0 +1,8 @@
+
+import scala.quoted.*
+
+inline val InlineStringVal = "abc"
+
+inline def withInlineVal = ${ qqq(InlineStringVal) }
+
+def qqq(s: String)(using Quotes): Expr[String] = Expr(s)
diff --git a/tests/pos-macros/i12196/Test_2.scala b/tests/pos-macros/i12196/Test_2.scala
new file mode 100644
index 000000000000..a4b3e340cb52
--- /dev/null
+++ b/tests/pos-macros/i12196/Test_2.scala
@@ -0,0 +1 @@
+def test = withInlineVal