diff --git a/compiler/src/dotty/tools/dotc/parsing/Parsers.scala b/compiler/src/dotty/tools/dotc/parsing/Parsers.scala
index 6577c6a12ff3..ecedf9c45249 100644
--- a/compiler/src/dotty/tools/dotc/parsing/Parsers.scala
+++ b/compiler/src/dotty/tools/dotc/parsing/Parsers.scala
@@ -2601,11 +2601,13 @@ object Parsers {
       if (isIdent(nme.raw.BAR)) { in.nextToken(); pattern1(location) :: patternAlts(location) }
       else Nil
 
-    /**  Pattern1     ::= Pattern2 [Ascription]
+    /**  Pattern1     ::= PatVar Ascription
+     *                  | SimpleLiteral Ascription
+     *                  | Pattern2
      */
     def pattern1(location: Location = Location.InPattern): Tree =
       val p = pattern2()
-      if in.token == COLON then
+      if (isVarPattern(p) || p.isInstanceOf[Number]) && in.token == COLON then
         in.nextToken()
         ascription(p, location)
       else p
diff --git a/docs/docs/internals/syntax.md b/docs/docs/internals/syntax.md
index 56648a81d4c2..40506f427361 100644
--- a/docs/docs/internals/syntax.md
+++ b/docs/docs/internals/syntax.md
@@ -263,7 +263,9 @@ TypeCaseClauses   ::=  TypeCaseClause { TypeCaseClause }
 TypeCaseClause    ::=  ‘case’ InfixType ‘=>’ Type [nl]
 
 Pattern           ::=  Pattern1 { ‘|’ Pattern1 }                                Alternative(pats)
-Pattern1          ::=  Pattern2 [‘:’ RefinedType]                               Bind(name, Typed(Ident(wildcard), tpe))
+Pattern1          ::=  PatVar ‘:’ RefinedType                                   Bind(name, Typed(Ident(wildcard), tpe))
+                    |  SimpleLiteral ‘:’ RefinedType                            Bind(name, Typed(Ident(wildcard), tpe))
+                    |  Pattern2
 Pattern2          ::=  [id ‘@’] InfixPattern                                    Bind(name, pat)
 InfixPattern      ::=  SimplePattern { id [nl] SimplePattern }                  InfixOp(pat, op, pat)
 SimplePattern     ::=  PatVar                                                   Ident(wildcard)
diff --git a/tests/neg/i10994.scala b/tests/neg/i10994.scala
new file mode 100644
index 000000000000..ce5cb2cf3df9
--- /dev/null
+++ b/tests/neg/i10994.scala
@@ -0,0 +1,2 @@
+def foo = true match
+  case (b: Boolean): Boolean => ()  // error