[wasm][asm.js] Require a number for fround literals.

src/asmjs/asm-typer.cc

Index: src/asmjs/asm-typer.cc
diff --git a/src/asmjs/asm-typer.cc b/src/asmjs/asm-typer.cc
index 0ac40ec6f7ad73d0c30bc6ded3ba706e43a071dd..af0b5310bf0b4174992505fb7fc12f83268558ef 100644
--- a/src/asmjs/asm-typer.cc
+++ b/src/asmjs/asm-typer.cc
@@ -2854,6 +2854,12 @@ AsmType* AsmTyper::VariableTypeAnnotations(
   // However, the errata doc (and actual programs), use integer values
   // with fround(..).
   // Skipping the check that would go here to enforce this.
+  // Checking instead the literal expression is at least a number.
+  if (!src_expr->raw_value()->IsNumber()) {
+    FAIL(initializer,
+         "Invalid float type annotation - expected numeric literal for call "
+         "to fround.");
+  }
 
   return AsmType::Float();
 }