diff --git a/CHANGELOG.md b/CHANGELOG.md
index c9eb542..8b5a166 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,8 @@
 
 ## [Unreleased](https://github.com/dalance/sv-parser/compare/v0.6.1...Unreleased) - ReleaseDate
 
+* [Fixed] parse error of cast
+
 ## [v0.6.1](https://github.com/dalance/sv-parser/compare/v0.6.0...v0.6.1) - 2020-02-09
 
 * [Changed] update str-concat
diff --git a/sv-parser-parser/src/declarations/net_and_variable_types.rs b/sv-parser-parser/src/declarations/net_and_variable_types.rs
index a5eae98..93ffcbc 100644
--- a/sv-parser-parser/src/declarations/net_and_variable_types.rs
+++ b/sv-parser-parser/src/declarations/net_and_variable_types.rs
@@ -12,7 +12,23 @@ pub(crate) fn casting_type(s: Span) -> IResult<Span, CastingType> {
         map(signing, |x| CastingType::Signing(Box::new(x))),
         map(keyword("string"), |x| CastingType::String(Box::new(x))),
         map(keyword("const"), |x| CastingType::Const(Box::new(x))),
-        map(constant_primary, |x| {
+        map(constant_primary_without_cast, |x| {
+            CastingType::ConstantPrimary(Box::new(x))
+        }),
+    ))(s)
+}
+
+#[recursive_parser]
+#[packrat_parser]
+#[tracable_parser]
+#[packrat_parser]
+pub(crate) fn constant_casting_type(s: Span) -> IResult<Span, CastingType> {
+    alt((
+        map(simple_type, |x| CastingType::SimpleType(Box::new(x))),
+        map(signing, |x| CastingType::Signing(Box::new(x))),
+        map(keyword("string"), |x| CastingType::String(Box::new(x))),
+        map(keyword("const"), |x| CastingType::Const(Box::new(x))),
+        map(constant_primary_without_cast, |x| {
             CastingType::ConstantPrimary(Box::new(x))
         }),
     ))(s)
diff --git a/sv-parser-parser/src/expressions/primaries.rs b/sv-parser-parser/src/expressions/primaries.rs
index 1ad2819..1b75e54 100644
--- a/sv-parser-parser/src/expressions/primaries.rs
+++ b/sv-parser-parser/src/expressions/primaries.rs
@@ -41,6 +41,42 @@ pub(crate) fn constant_primary(s: Span) -> IResult<Span, ConstantPrimary> {
     ))(s)
 }
 
+#[tracable_parser]
+#[packrat_parser]
+pub(crate) fn constant_primary_without_cast(s: Span) -> IResult<Span, ConstantPrimary> {
+    alt((
+        // BNF-WA
+        map(keyword("$"), |x| ConstantPrimary::Dollar(Box::new(x))),
+        map(keyword("null"), |x| ConstantPrimary::Null(Box::new(x))),
+        map(constant_assignment_pattern_expression, |x| {
+            ConstantPrimary::ConstantAssignmentPatternExpression(Box::new(x))
+        }),
+        map(primary_literal, |x| {
+            ConstantPrimary::PrimaryLiteral(Box::new(x))
+        }),
+        constant_primary_mintypmax_expression,
+        map(
+            terminated(constant_function_call, peek(not(one_of("[.")))),
+            |x| ConstantPrimary::ConstantFunctionCall(Box::new(x)),
+        ),
+        constant_primary_ps_parameter,
+        constant_primary_specparam,
+        map(genvar_identifier, |x| {
+            ConstantPrimary::GenvarIdentifier(Box::new(x))
+        }),
+        constant_primary_formal_port,
+        constant_primary_enum,
+        constant_primary_concatenation,
+        constant_primary_multiple_concatenation,
+        map(constant_let_expression, |x| {
+            ConstantPrimary::ConstantLetExpression(Box::new(x))
+        }),
+        map(type_reference, |x| {
+            ConstantPrimary::TypeReference(Box::new(x))
+        }),
+    ))(s)
+}
+
 #[tracable_parser]
 #[packrat_parser]
 pub(crate) fn constant_primary_ps_parameter(s: Span) -> IResult<Span, ConstantPrimary> {
@@ -402,7 +438,7 @@ pub(crate) fn constant_select(s: Span) -> IResult<Span, ConstantSelect> {
 #[tracable_parser]
 #[packrat_parser]
 pub(crate) fn constant_cast(s: Span) -> IResult<Span, ConstantCast> {
-    let (s, a) = casting_type(s)?;
+    let (s, a) = constant_casting_type(s)?;
     let (s, b) = symbol("'")(s)?;
     let (s, c) = paren(constant_expression)(s)?;
     Ok((s, ConstantCast { nodes: (a, b, c) }))
diff --git a/sv-parser-parser/src/tests.rs b/sv-parser-parser/src/tests.rs
index 11ef683..793d569 100644
--- a/sv-parser-parser/src/tests.rs
+++ b/sv-parser-parser/src/tests.rs
@@ -418,6 +418,11 @@ mod unit {
             r##"module test(); specify $setup(posedge CSB, edge[01,0x,x1,1x] CL, tps, a); endspecify endmodule"##,
             Ok((_, _))
         );
+        test!(
+            source_text,
+            r##"module a; assign a = a[$clog2(a)'(a)]; endmodule"##,
+            Ok((_, _))
+        );
     }
 }
 
@@ -15876,10 +15881,6 @@ mod spec {
 
 #[test]
 fn debug() {
-    test!(
-        source_text,
-        r##"module a; initial begin #1 ps[idx] = 1'b1; end endmodule"##,
-        Ok((_, _))
-    );
+    test!(expression, r##"a[$clog2(a)'(a)]"##, Ok((_, _)));
     nom_tracable::cumulative_histogram();
 }