diff --git a/partiql-parser/src/main/antlr/PartiQLParser.g4 b/partiql-parser/src/main/antlr/PartiQLParser.g4
index ba0614136..54be03c23 100644
--- a/partiql-parser/src/main/antlr/PartiQLParser.g4
+++ b/partiql-parser/src/main/antlr/PartiQLParser.g4
@@ -622,6 +622,8 @@ comparisonOp
 otherOp
     : OPERATOR
     | AMPERSAND
+    // TODO introduce a separate lexical mode for GPML MATCH expressions (https://github.com/partiql/partiql-lang-kotlin/issues/1512)
+    //  This will eliminiate the need for this `AMPERSAND` parse branch.
     ;
 
 // TODO : Opreator precedence of `otherOp` may change in the future.
diff --git a/partiql-parser/src/main/antlr/PartiQLTokens.g4 b/partiql-parser/src/main/antlr/PartiQLTokens.g4
index c43855a20..20e2d9425 100644
--- a/partiql-parser/src/main/antlr/PartiQLTokens.g4
+++ b/partiql-parser/src/main/antlr/PartiQLTokens.g4
@@ -374,6 +374,8 @@ fragment OpBasicEnd
 fragment OpSpecial
     : [~@#%^?]  // TODO support backtick (`)?
     // graph patterns are not matched
+    // TODO make GPML MATCH patterns a separate lexical mode (https://github.com/partiql/partiql-lang-kotlin/issues/1512)
+    //  Creating a separate lexical mode will allow us to get rid of the following semantic predicates.
     | '|' {_input.LA(1) != '!'}?
     | '!' {_input.LA(1) != '%'}?
     | '&' {_input.LA(1) != '%'}?