Properly print @use and @consume parameters

Author: Linyxus

compiler/src/dotty/tools/dotc/core/Definitions.scala

@@ -1117,7 +1117,7 @@ class Definitions {
 
   // Set of annotations that are not printed in types except under -Yprint-debug
   @tu lazy val SilentAnnots: Set[Symbol] =
-    Set(InlineParamAnnot, ErasedParamAnnot, RefineOverrideAnnot, SilentIntoAnnot)
+    Set(InlineParamAnnot, ErasedParamAnnot, RefineOverrideAnnot, SilentIntoAnnot, UseAnnot, ConsumeAnnot)
 
   // A list of annotations that are commonly used to indicate that a field/method argument or return
   // type is not null. These annotations are used by the nullification logic in JavaNullInterop to

compiler/src/dotty/tools/dotc/printing/PlainPrinter.scala

@@ -379,7 +379,11 @@ class PlainPrinter(_ctx: Context) extends Printer {
   protected def paramsText(lam: LambdaType): Text = {
     def paramText(ref: ParamRef) =
       val erased = ref.underlying.hasAnnotation(defn.ErasedParamAnnot)
-      keywordText("erased ").provided(erased) ~ ParamRefNameString(ref) ~ hashStr(lam) ~ toTextRHS(ref.underlying, isParameter = true)
+      def maybeAnnotsText(sym: ClassSymbol): Text =
+        Str(s"@${sym.name} ").provided(ref.underlying.hasAnnotation(sym))
+      keywordText("erased ").provided(erased)
+        ~ maybeAnnotsText(defn.UseAnnot) ~ maybeAnnotsText(defn.ConsumeAnnot)
+        ~ ParamRefNameString(ref) ~ hashStr(lam) ~ toTextRHS(ref.underlying, isParameter = true)
     Text(lam.paramRefs.map(paramText), ", ")
   }
 

tests/neg-custom-args/captures/unbox-overrides.check

@@ -1,21 +1,21 @@
 -- [E164] Declaration Error: tests/neg-custom-args/captures/unbox-overrides.scala:8:6 ----------------------------------
 8 |  def foo(x: C): C        // error
   |      ^
-  |error overriding method foo in trait A of type (x: C): C;
+  |error overriding method foo in trait A of type (@use x: C): C;
   |  method foo of type (x: C): C has a parameter x with different @use status than the corresponding parameter in the overridden definition
   |
   | longer explanation available when compiling with `-explain`
 -- [E164] Declaration Error: tests/neg-custom-args/captures/unbox-overrides.scala:9:6 ----------------------------------
 9 |  def bar(@use x: C): C // error
   |      ^
   |error overriding method bar in trait A of type (x: C): C;
-  |  method bar of type (x: C): C has a parameter x with different @use status than the corresponding parameter in the overridden definition
+  |  method bar of type (@use x: C): C has a parameter x with different @use status than the corresponding parameter in the overridden definition
   |
   | longer explanation available when compiling with `-explain`
 -- [E164] Declaration Error: tests/neg-custom-args/captures/unbox-overrides.scala:15:15 --------------------------------
 15 |abstract class C extends A[C], B2 // error
    |               ^
-   |error overriding method foo in trait A of type (x: C): C;
+   |error overriding method foo in trait A of type (@use x: C): C;
    |  method foo in trait B2 of type (x: C): C has a parameter x with different @use status than the corresponding parameter in the overridden definition
    |
    | longer explanation available when compiling with `-explain`

tests/neg-custom-args/captures/unsound-reach-4.check

@@ -18,9 +18,9 @@
 17 |  def use(@consume x: F): File^ = x // error @consume override
    |      ^
    |      error overriding method use in trait Foo of type (x: File^): box File^;
-   |        method use of type (x: File^): File^² has incompatible type
+   |        method use of type (@consume x: File^): File^² has incompatible type
    |
    |      where:    ^  refers to the universal root capability
-   |                ^² refers to a root capability associated with the result type of (x: File^): File^²
+   |                ^² refers to a root capability associated with the result type of (@consume x: File^): File^²
    |
    | longer explanation available when compiling with `-explain`