From 1c57fd8914a9f12e2e50ccf9bb61fe0cb0773bf8 Mon Sep 17 00:00:00 2001
From: Martin Odersky <odersky@gmail.com>
Date: Mon, 9 Dec 2019 09:56:34 +0100
Subject: [PATCH 1/2] Fix infix of match

`match` should have the same precedence as alphanumeric operators. This
means that `a match { ... } + 1` should give a syntax error.
---
 .../src/dotty/tools/dotc/parsing/Parsers.scala     | 14 ++++++++++----
 tests/neg/match-infix.scala                        |  3 +++
 2 files changed, 13 insertions(+), 4 deletions(-)
 create mode 100644 tests/neg/match-infix.scala

diff --git a/compiler/src/dotty/tools/dotc/parsing/Parsers.scala b/compiler/src/dotty/tools/dotc/parsing/Parsers.scala
index 992b98fffbf5..297c44d1a07d 100644
--- a/compiler/src/dotty/tools/dotc/parsing/Parsers.scala
+++ b/compiler/src/dotty/tools/dotc/parsing/Parsers.scala
@@ -983,9 +983,15 @@ object Parsers {
         }
         else
           val t = reduceStack(base, top, minPrec, leftAssoc = true, in.name, isType)
-          if !isType && in.token == MATCH then recur(matchClause(t))
+          if !isType && in.token == MATCH then recurAtMinPrec(matchClause(t))
           else t
 
+      def recurAtMinPrec(top: Tree): Tree =
+        if isIdent && isOperator && precedence(in.name) == minInfixPrec
+           || in.token == MATCH
+        then recur(top)
+        else top
+
       recur(first)
     }
 
@@ -2758,8 +2764,8 @@ object Parsers {
     /** OLD: GivenTypes   ::=  AnnotType {‘,’ AnnotType}
      *  NEW: GivenTypes   ::=  Type {‘,’ Type}
      */
-    def givenTypes(newStyle: Boolean, nparams: Int, ofClass: Boolean): List[ValDef] =
-      val tps = commaSeparated(() => if newStyle then typ() else annotType())
+    def givenTypes(nparams: Int, ofClass: Boolean): List[ValDef] =
+      val tps = commaSeparated(typ)
       var counter = nparams
       def nextIdx = { counter += 1; counter }
       val paramFlags = if ofClass then Private | Local | ParamAccessor else Param
@@ -2862,7 +2868,7 @@ object Parsers {
                 || startParamTokens.contains(in.token)
                 || isIdent && (in.name == nme.inline || in.lookaheadIn(BitSet(COLON)))
               if isParams then commaSeparated(() => param())
-              else givenTypes(true, nparams, ofClass)
+              else givenTypes(nparams, ofClass)
           checkVarArgsRules(clause)
           clause
       }
diff --git a/tests/neg/match-infix.scala b/tests/neg/match-infix.scala
new file mode 100644
index 000000000000..12b57f4dc418
--- /dev/null
+++ b/tests/neg/match-infix.scala
@@ -0,0 +1,3 @@
+def f = 1 + 1 match {
+  case 2 => 3
+} + 1   // error // error

From dff5ade7e84df3c0acc94ab9c44bf81bb752fb47 Mon Sep 17 00:00:00 2001
From: Martin Odersky <odersky@gmail.com>
Date: Mon, 9 Dec 2019 10:51:29 +0100
Subject: [PATCH 2/2] Avoid lookahead in constrApps

---
 compiler/src/dotty/tools/dotc/parsing/Parsers.scala | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/compiler/src/dotty/tools/dotc/parsing/Parsers.scala b/compiler/src/dotty/tools/dotc/parsing/Parsers.scala
index 297c44d1a07d..34f871ba7a5b 100644
--- a/compiler/src/dotty/tools/dotc/parsing/Parsers.scala
+++ b/compiler/src/dotty/tools/dotc/parsing/Parsers.scala
@@ -3483,12 +3483,11 @@ object Parsers {
       val t = constrApp()
       val ts =
         if in.token == WITH then
-          val lookahead = in.LookaheadScanner(indent = true)
-          lookahead.nextToken()
-          if templateCanFollow && (lookahead.token == LBRACE || lookahead.token == INDENT) then
+          in.nextToken()
+          newLineOptWhenFollowedBy(LBRACE)
+          if templateCanFollow && (in.token == LBRACE || in.token == INDENT) then
             Nil
           else
-            in.nextToken()
             checkNotWithAtEOL()
             constrApps(commaOK, templateCanFollow)
         else if commaOK && in.token == COMMA then