diff --git a/asm-to-pil/src/vm_to_constrained.rs b/asm-to-pil/src/vm_to_constrained.rs
index 33d4d540f..c2dd382ad 100644
--- a/asm-to-pil/src/vm_to_constrained.rs
+++ b/asm-to-pil/src/vm_to_constrained.rs
@@ -1289,7 +1289,7 @@ machine Main {
             }
 
             trait ArraySum<T> {
-                array_sum: T[4 + 1] -> DoubleOpt<T>,
+                array_sum: T[4 + 1] -> DoubleOpt<T>;
             }
         }
 
diff --git a/ast/src/parsed/display.rs b/ast/src/parsed/display.rs
index 9b199b1e7..046dd61ad 100644
--- a/ast/src/parsed/display.rs
+++ b/ast/src/parsed/display.rs
@@ -584,7 +584,7 @@ impl<E: Display> Display for TraitDeclaration<E> {
             name = self.name,
             type_vars = self.type_vars.iter().format(", "),
             functions = indent(
-                self.functions.iter().map(|m| format!("{m},\n")).format(""),
+                self.functions.iter().map(|m| format!("{m};\n")).format(""),
                 1
             )
         )
diff --git a/parser/src/lib.rs b/parser/src/lib.rs
index 186a942e0..0010cb1a4 100644
--- a/parser/src/lib.rs
+++ b/parser/src/lib.rs
@@ -485,12 +485,12 @@ namespace N(2);
     fn parse_trait() {
         let input = r#"
     trait Add<T> {
-        add: T, T -> T,
+        add: T, T -> T;
     }"#;
 
         let expected = r#"
     trait Add<T> {
-        add: T, T -> T,
+        add: T, T -> T;
     }"#;
 
         let printed = format!("{}", parse(Some("input"), input).unwrap_err_to_stderr());
@@ -501,12 +501,12 @@ namespace N(2);
     fn parse_trait_multi_params() {
         let input = r#"
     trait Add<T, Q> {
-        add: T, T -> Q,
+        add: T, T -> Q;
     }"#;
 
         let expected = r#"
     trait Add<T, Q> {
-        add: T, T -> Q,
+        add: T, T -> Q;
     }"#;
 
         let printed = format!("{}", parse(Some("input"), input).unwrap_err_to_stderr());
@@ -518,7 +518,7 @@ namespace N(2);
     fn parse_trait_no_type_vars() {
         let input = r#"
     trait Add {
-        add: int, int -> int,
+        add: int, int -> int;
     }"#;
 
         let _ = format!("{}", parse(Some("input"), input).unwrap_err_to_stderr());
@@ -528,12 +528,12 @@ namespace N(2);
     fn parse_trait_multi_params2() {
         let input = r#"
     trait Iterator<S, I> {
-        next: S -> (S, Option<I>),
+        next: S -> (S, Option<I>);
     }"#;
 
         let expected = r#"
     trait Iterator<S, I> {
-        next: S -> (S, Option<I>),
+        next: S -> (S, Option<I>);
     }"#;
 
         let printed = format!("{}", parse(Some("input"), input).unwrap_err_to_stderr());
diff --git a/parser/src/powdr.lalrpop b/parser/src/powdr.lalrpop
index eb65e6119..bf22e4683 100644
--- a/parser/src/powdr.lalrpop
+++ b/parser/src/powdr.lalrpop
@@ -691,11 +691,11 @@ TraitVars: Vec<String> = {
 
 TraitFunctions: Vec<TraitFunction<Expression>> = {
     => vec![],
-    <mut list:( <TraitFunction> "," )*> <end:TraitFunction> ","  => { list.push(end); list }
+    <mut list:( <TraitFunction> ";" )*> <end:TraitFunction> ";"  => { list.push(end); list }
 }
 
 TraitFunction: TraitFunction<Expression> = {
-    <name:Identifier> ":" <params:TypeTermList> "->" <value:TypeTermBox> => TraitFunction { name, ty: Type::Function(FunctionType{params, value}) }
+    <name:Identifier> ":" <ty:Type> => TraitFunction { name, ty }
 }
 
 
diff --git a/pil-analyzer/tests/parse_display.rs b/pil-analyzer/tests/parse_display.rs
index fd3455bab..e31d42115 100644
--- a/pil-analyzer/tests/parse_display.rs
+++ b/pil-analyzer/tests/parse_display.rs
@@ -718,12 +718,12 @@ namespace T(8);
 #[test]
 fn trait_def() {
     let input = "trait Add<T, Q> {
-        add: T, T -> Q,
+        add: T, T -> Q;
     }
 ";
 
     let expected = "    trait Add<T, Q> {
-        add: T, T -> Q,
+        add: T, T -> Q;
     }
 ";
 
@@ -734,12 +734,12 @@ fn trait_def() {
 #[test]
 fn array_type_trait() {
     let input = "trait ArraySum<T> {
-        array_sum: T[4 + 1] -> T,
+        array_sum: T[4 + 1] -> T;
     }
 ";
 
     let expected = "    trait ArraySum<T> {
-        array_sum: T[5] -> T,
+        array_sum: T[5] -> T;
     }
 ";
 
@@ -751,7 +751,7 @@ fn array_type_trait() {
 #[should_panic = "Duplicate symbol definition: Add"]
 fn trait_enum_collisions() {
     let input = "trait Add<T, Q> {
-        add: T, T -> Q,
+        add: T, T -> Q;
     }
     enum Add {
         X
diff --git a/test_data/asm/trait_parsing.asm b/test_data/asm/trait_parsing.asm
index 99d2579c2..1ce21e363 100644
--- a/test_data/asm/trait_parsing.asm
+++ b/test_data/asm/trait_parsing.asm
@@ -5,7 +5,7 @@ mod types {
     }
 
     trait ArraySum<T> {
-        array_sum: T[4 + 1] -> DoubleOpt<T>,
+        array_sum: T[4 + 1] -> DoubleOpt<T>;
     }
 }