fix: Expression passed to evaluateCondition asserted to be valid (AssemblyScript#2013)

Author: romdotdog

src/compiler.ts

@@ -10067,7 +10067,11 @@ export class Compiler extends DiagnosticEmitter {
 
   /** Evaluates a boolean condition, determining whether it is TRUE, FALSE or UNKNOWN. */
   evaluateCondition(expr: ExpressionRef): ConditionKind {
-    assert(getExpressionType(expr) == TypeRef.I32);
+    let type = getExpressionType(expr);
+    if (type == TypeRef.Unreachable)
+      return ConditionKind.UNKNOWN;
+
+    assert(type == TypeRef.I32);
     var module = this.module;
     var evaled = module.runExpression(expr, ExpressionRunnerFlags.Default);
     if (evaled) {

tests/compiler/unknown-bool-ident.json

@@ -0,0 +1,8 @@
+{
+  "asc_flags": [
+  ],
+  "stderr": [
+    "TS2304: Cannot find name 'unknown_var'.",
+    "EOF"
+  ]
+}

tests/compiler/unknown-bool-ident.ts

@@ -0,0 +1,2 @@
+if (1 <= unknown_var) {}
+ERROR("EOF");