Port Applications errors to the new scheme

Author: ausmarton

compiler/src/dotty/tools/dotc/reporting/diagnostic/ErrorMessageID.scala

@@ -157,7 +157,8 @@ enum ErrorMessageID extends java.lang.Enum[ErrorMessageID] {
     AbstractCannotBeUsedForObjectsID,
     ModifierRedundantForObjectsID,
     TypedCaseDoesNotExplicitlyExtendTypedEnumID,
-    IllegalRedefinitionOfStandardKindID
+    IllegalRedefinitionOfStandardKindID,
+    UnexpectedPatternForSummonFromID
 
   def errorNumber = ordinal - 2
 }

compiler/src/dotty/tools/dotc/reporting/diagnostic/messages.scala

@@ -2469,4 +2469,25 @@ object messages {
            | Please choose a different name to avoid conflicts
            |""".stripMargin
   }
+
+  case class UnexpectedPatternForSummonFrom(tree: Tree[_])(implicit ctx: Context)
+    extends Message(UnexpectedPatternForSummonFromID) {
+    val kind: String = "Syntax"
+    val msg: String = em"Unexpected pattern for summonFrom. Expected ${hl("`x: T`")} or ${hl("`_`")}"
+
+    val explanation: String =
+      em"""|The pattern "${tree.show}" provided in the ${hl("case")} expression of the ${hl("summonFrom")},
+           | needs to be of the form ${hl("`x: T`")} or ${hl("`_`")}.
+           |
+           | Example usage:
+           | inline def a = summonFrom {
+           |  case x: T => ???
+           | }
+           |
+           | or
+           | inline def a = summonFrom {
+           |  case _ => ???
+           | }
+           |""".stripMargin
+  }
 }

compiler/src/dotty/tools/dotc/typer/Applications.scala

@@ -29,6 +29,7 @@ import config.Printers.{overload, typr, unapp}
 import TypeApplications._
 
 import reporting.diagnostic.Message
+import reporting.diagnostic.messages.UnexpectedPatternForSummonFrom
 import reporting.trace
 import Constants.{Constant, IntTag, LongTag}
 import dotty.tools.dotc.reporting.diagnostic.messages.{UnapplyInvalidReturnType, NotAnExtractor, UnapplyInvalidNumberOfArguments}
@@ -916,7 +917,7 @@ trait Applications extends Compatibility {
                   case CaseDef(Bind(_, Typed(_: Ident, _)), _, _) => // OK
                   case CaseDef(Ident(name), _, _) if name == nme.WILDCARD => // Ok
                   case CaseDef(pat, _, _) =>
-                    ctx.error("Unexpected pattern for summonFrom. Expeced `x: T` or `_`", pat.sourcePos)
+                    ctx.error(UnexpectedPatternForSummonFrom(pat), pat.sourcePos)
                 }
                 typed(untpd.InlineMatch(EmptyTree, cases).withSpan(arg.span), pt)
               case _ =>

compiler/test/dotty/tools/dotc/reporting/ErrorMessagesTests.scala

@@ -1805,4 +1805,38 @@ class ErrorMessagesTests extends ErrorMessagesTest {
         assertEquals("class", kind)
         assertEquals("Any", name.toString)
       }
+
+  @Test def unexpectedPatternForSummonFrom =
+    checkMessagesAfter(RefChecks.name) {
+      """import compiletime.summonFrom
+        |inline def a = summonFrom {
+        |  case x => ???
+        |}
+      """.stripMargin
+    }
+      .expect { (ictx, messages) ⇒
+        implicit val ctx: Context = ictx
+        assertMessageCount(1, messages)
+        val errorMsg = messages.head.msg
+        val UnexpectedPatternForSummonFrom(x) :: Nil = messages
+        assertEquals("Unexpected pattern for summonFrom. Expected `x: T` or `_`", errorMsg)
+        assertEquals("x", x.show)
+      }
+
+  @Test def unexpectedPatternForSummonWithPatternBinder =
+    checkMessagesAfter(RefChecks.name) {
+      """import compiletime.summonFrom
+        |inline def a = summonFrom {
+        |  case x@String => ???
+        |}
+      """.stripMargin
+    }
+      .expect { (ictx, messages) ⇒
+        implicit val ctx: Context = ictx
+        assertMessageCount(1, messages)
+        val errorMsg = messages.head.msg
+        val UnexpectedPatternForSummonFrom(x) :: Nil = messages
+        assertEquals("Unexpected pattern for summonFrom. Expected `x: T` or `_`", errorMsg)
+        assertEquals("given x @ String", x.show)
+      }
 }

tests/neg/SummonFrom.check

@@ -0,0 +1,12 @@
+-- [E150] Syntax Error: tests/neg/SummonFrom.scala:4:7 -----------------------------------------------------------------
+4 |  case x => ??? // error
+  |       ^
+  |       Unexpected pattern for summonFrom. Expected `x: T` or `_`
+
+longer explanation available when compiling with `-explain`
+-- [E150] Syntax Error: tests/neg/SummonFrom.scala:8:7 -----------------------------------------------------------------
+8 |  case x@String => ??? // error
+  |       ^^^^^^^^
+  |       Unexpected pattern for summonFrom. Expected `x: T` or `_`
+
+longer explanation available when compiling with `-explain`

tests/neg/SummonFrom.scala

@@ -0,0 +1,9 @@
+import compiletime.summonFrom
+
+inline def a = summonFrom {
+  case x => ??? // error
+}
+
+inline def b = summonFrom {
+  case x@String => ??? // error
+}