diff --git a/compiler/can/tests/test_can.rs b/compiler/can/tests/test_can.rs
index 00014c9ce8..e90768c12c 100644
--- a/compiler/can/tests/test_can.rs
+++ b/compiler/can/tests/test_can.rs
@@ -139,6 +139,21 @@ mod test_can {
         );
     }
 
+    #[test]
+    fn float_double_dot() {
+        let string = "1.1.1";
+        let region = Region::zero();
+
+        assert_can(
+            &string.clone(),
+            RuntimeError(RuntimeError::InvalidFloat(
+                FloatErrorKind::Error,
+                region,
+                string.into(),
+            )),
+        );
+    }
+
     #[test]
     fn zero() {
         assert_can_num("0", 0);
diff --git a/compiler/parse/src/number_literal.rs b/compiler/parse/src/number_literal.rs
index 9f151731b8..f38a700f6f 100644
--- a/compiler/parse/src/number_literal.rs
+++ b/compiler/parse/src/number_literal.rs
@@ -40,11 +40,10 @@ fn chomp_number_base<'a>(
     bytes: &'a [u8],
     state: State<'a>,
 ) -> ParseResult<'a, Expr<'a>, Number> {
-    let (_is_float, mut chomped) = chomp_number(bytes);
-    chomped += 2 + (is_negative as usize);
+    let (_is_float, chomped) = chomp_number(bytes);
 
     match parse_utf8(&bytes[0..chomped]) {
-        Ok(string) => match state.advance_without_indenting(chomped) {
+        Ok(string) => match state.advance_without_indenting(chomped + 2 + is_negative as usize) {
             Ok(new) => {
                 // all is well
                 Ok((
@@ -73,7 +72,7 @@ fn chomp_number_dec<'a>(
     bytes: &'a [u8],
     state: State<'a>,
 ) -> ParseResult<'a, Expr<'a>, Number> {
-    let (is_float, mut chomped) = chomp_number(bytes);
+    let (is_float, chomped) = chomp_number(bytes);
 
     if is_negative && chomped == 0 {
         // we're probably actually looking at unary negation here
@@ -85,11 +84,9 @@ fn chomp_number_dec<'a>(
         return Err((Progress::NoProgress, Number::End, state));
     }
 
-    chomped += is_negative as usize;
+    let string = unsafe { from_utf8_unchecked(&state.bytes[0..chomped + is_negative as usize]) };
 
-    let string = unsafe { from_utf8_unchecked(&state.bytes[0..chomped]) };
-
-    match state.advance_without_indenting(chomped) {
+    match state.advance_without_indenting(chomped + is_negative as usize) {
         Ok(new) => {
             // all is well
             Ok((
diff --git a/compiler/reporting/tests/test_reporting.rs b/compiler/reporting/tests/test_reporting.rs
index ef03df1c88..254bb66f16 100644
--- a/compiler/reporting/tests/test_reporting.rs
+++ b/compiler/reporting/tests/test_reporting.rs
@@ -5134,4 +5134,30 @@ mod test_reporting {
             ),
         )
     }
+
+    #[test]
+    fn number_double_dot() {
+        report_problem_as(
+            indoc!(
+                r#"
+                1.1.1
+                "#
+            ),
+            indoc!(
+                r#"
+                ── SYNTAX PROBLEM ──────────────────────────────────────────────────────────────
+                
+                This float literal contains an invalid digit:
+                
+                1│  1.1.1
+                    ^^^^^
+                
+                Floating point literals can only contain the digits 0-9, or use
+                scientific notation 10e4
+                
+                Tip: Learn more about number literals at TODO
+            "#
+            ),
+        )
+    }
 }