diff --git a/Ghidra/Features/Base/src/main/java/ghidra/app/util/parser/FunctionSignatureParser.java b/Ghidra/Features/Base/src/main/java/ghidra/app/util/parser/FunctionSignatureParser.java
index 8a74a413c9..603eac7cd5 100644
--- a/Ghidra/Features/Base/src/main/java/ghidra/app/util/parser/FunctionSignatureParser.java
+++ b/Ghidra/Features/Base/src/main/java/ghidra/app/util/parser/FunctionSignatureParser.java
@@ -206,7 +206,7 @@ public class FunctionSignatureParser {
 		// attempt to separate trailing parameter name from datatype and reparse
 		int spaceIndex = arg.lastIndexOf(' ');
 		if (spaceIndex < 0) {
-			throw new ParseException("Can't resolve datatype: " + dt);
+			throw new ParseException("Can't resolve datatype: " + arg);
 		}
 		int starIndex = arg.lastIndexOf('*');
 		int nameIndex = Math.max(spaceIndex, starIndex) + 1;
diff --git a/Ghidra/Features/Base/src/main/java/ghidra/util/data/DataTypeParser.java b/Ghidra/Features/Base/src/main/java/ghidra/util/data/DataTypeParser.java
index 3dc3e1a8b7..e46cfd75dd 100644
--- a/Ghidra/Features/Base/src/main/java/ghidra/util/data/DataTypeParser.java
+++ b/Ghidra/Features/Base/src/main/java/ghidra/util/data/DataTypeParser.java
@@ -416,7 +416,7 @@ public class DataTypeParser {
 			// handle C primitives (e.g.  long long, unsigned long int, etc.)
 			DataType dataType = DataTypeUtilities.getCPrimitiveDataType(baseName);
 			if (dataType != null) {
-				return dataType;
+				return dataType.clone(dtm);
 			}
 
 			dtm.findDataTypes(baseName, list);
diff --git a/Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/data/ParameterDefinitionImpl.java b/Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/data/ParameterDefinitionImpl.java
index 647130b0f5..25384ef8ca 100644
--- a/Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/data/ParameterDefinitionImpl.java
+++ b/Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/data/ParameterDefinitionImpl.java
@@ -48,7 +48,8 @@ public class ParameterDefinitionImpl implements ParameterDefinition {
 	 * @throws IllegalArgumentException if invalid parameter datatype specified
 	 */
 	protected ParameterDefinitionImpl(String name, DataType dataType, String comment, int ordinal) {
-		this.dataType = validateDataType(dataType, null, false);
+		this.dataType = validateDataType(dataType,
+			dataType != null ? dataType.getDataTypeManager() : null, false);
 		this.name = name;
 		this.comment = comment;
 		this.ordinal = ordinal;