feat: add analysis error for use of block-height in Clarity 3

clarity/src/vm/analysis/errors.rs

@@ -136,6 +136,7 @@ pub enum CheckErrors {
     GetBurnBlockInfoExpectPropertyName,
 
     NameAlreadyUsed(String),
+    ReservedWord(String),
 
     // expect a function, or applying a function to a list
     NonFunctionApplication,
@@ -408,6 +409,7 @@ impl DiagnosableError for CheckErrors {
             CheckErrors::GetBlockInfoExpectPropertyName => "missing property name for block info introspection".into(),
             CheckErrors::GetBurnBlockInfoExpectPropertyName => "missing property name for burn block info introspection".into(),
             CheckErrors::NameAlreadyUsed(name) => format!("defining '{}' conflicts with previous value", name),
+            CheckErrors::ReservedWord(name) => format!("{name} is a reserved word"),
             CheckErrors::NonFunctionApplication => "expecting expression of type function".into(),
             CheckErrors::ExpectedListApplication => "expecting expression of type list".into(),
             CheckErrors::ExpectedSequence(found_type) => format!("expecting expression of type 'list', 'buff', 'string-ascii' or 'string-utf8' - found '{}'", found_type),

clarity/src/vm/analysis/type_checker/mod.rs

@@ -84,3 +84,21 @@ impl FunctionType {
         }
     }
 }
+
+fn is_reserved_word_v3(word: &str) -> bool {
+    match word {
+        "block-height" => true,
+        _ => false,
+    }
+}
+
+/// Is this a reserved word that should trigger an analysis error for the given
+/// Clarity version? Note that most of the reserved words do not trigger an
+/// analysis error, but will trigger an error at runtime. This should likely be
+/// changed in a future Clarity version.
+pub fn is_reserved_word(word: &str, version: ClarityVersion) -> bool {
+    match version {
+        ClarityVersion::Clarity1 | ClarityVersion::Clarity2 => false,
+        ClarityVersion::Clarity3 => is_reserved_word_v3(word),
+    }
+}

clarity/src/vm/analysis/type_checker/v2_1/contexts.rs

@@ -19,6 +19,7 @@ use std::collections::BTreeMap;
 use hashbrown::{HashMap, HashSet};
 
 use crate::vm::analysis::errors::{CheckError, CheckErrors, CheckResult};
+use crate::vm::analysis::type_checker::is_reserved_word;
 use crate::vm::analysis::types::ContractAnalysis;
 use crate::vm::contexts::MAX_CONTEXT_DEPTH;
 use crate::vm::representations::{ClarityName, SymbolicExpression};
@@ -128,6 +129,7 @@ impl TraitContext {
 }
 
 pub struct ContractContext {
+    clarity_version: ClarityVersion,
     contract_identifier: QualifiedContractIdentifier,
     map_types: HashMap<ClarityName, (TypeSignature, TypeSignature)>,
     variable_types: HashMap<ClarityName, TypeSignature>,
@@ -147,6 +149,7 @@ impl ContractContext {
         clarity_version: ClarityVersion,
     ) -> ContractContext {
         ContractContext {
+            clarity_version,
             contract_identifier,
             variable_types: HashMap::new(),
             private_function_types: HashMap::new(),
@@ -168,6 +171,10 @@ impl ContractContext {
     }
 
     pub fn check_name_used(&self, name: &str) -> CheckResult<()> {
+        if is_reserved_word(name, self.clarity_version) {
+            return Err(CheckError::new(CheckErrors::ReservedWord(name.to_string())));
+        }
+
         if self.variable_types.contains_key(name)
             || self.persisted_variable_types.contains_key(name)
             || self.private_function_types.contains_key(name)