Add regression tests (#17388)

Closes #13376

Author: smarter

tests/neg-macros/i13376a.scala

@@ -0,0 +1,6 @@
+import scala.quoted.*
+trait C:
+  type T
+  def foo: T
+inline def makro(inline x: C): x.T = ${ impl[x.type]('x) } // error // error
+def impl[CC <: C](xp: Expr[CC])(using Quotes): Expr[CC#T] = '{ $xp.foo }

tests/neg-macros/i13376b.scala

@@ -0,0 +1,6 @@
+import scala.quoted.*
+trait C:
+  type T
+  def foo: T
+inline def makro(x: C): x.T = ${ impl[x.type]('x) }
+def impl[CC <: C](xp: Expr[CC])(using Quotes): Expr[CC#T] = '{ $xp.foo } // error

tests/pos-macros/i13376a.scala

@@ -0,0 +1,7 @@
+import scala.quoted.*
+trait C:
+  type T
+  def foo: T
+inline def makro(x: C): x.T = ${ impl[x.T]('x) }
+def impl[U: Type](xp: Expr[C { def foo: U }])(using Quotes): Expr[U] =
+  '{ $xp.foo }

tests/pos-macros/i13376b.scala

@@ -0,0 +1,7 @@
+import scala.quoted.*
+trait C:
+  type T
+  def foo: T
+inline def makro(inline x: C): C#T = ${ impl('x) }
+def impl[U: Type](xp: Expr[C { def foo: U }])(using Quotes): Expr[U] =
+  '{ $xp.foo }