diff --git a/src/check/Check.zig b/src/check/Check.zig
index 723bc3d52d..dff7f48a55 100644
--- a/src/check/Check.zig
+++ b/src/check/Check.zig
@@ -1540,16 +1540,15 @@ fn checkBinopExpr(self: *Self, expr_idx: CIR.Expr.Idx, expr_region: Region, bino
             const rhs_var = @as(Var, @enumFromInt(@intFromEnum(binop.rhs)));
             const result_var = @as(Var, @enumFromInt(@intFromEnum(expr_idx)));
 
-            // Create a fresh number variable for the operation
+            // Create a SINGLE fresh number variable for the operation
+            // All operands and the result must be the same numeric type
             const num_content = Content{ .structure = .{ .num = .{ .num_unbound = .{ .sign_needed = false, .bits_needed = 0 } } } };
-            const num_var_lhs = try self.freshFromContent(num_content, expr_region);
-            const num_var_rhs = try self.freshFromContent(num_content, expr_region);
-            const num_var_result = try self.freshFromContent(num_content, expr_region);
+            const num_var = try self.freshFromContent(num_content, expr_region);
 
-            // Unify lhs, rhs, and result with the number type
-            _ = try self.unify(num_var_lhs, lhs_var);
-            _ = try self.unify(num_var_rhs, rhs_var);
-            _ = try self.unify(result_var, num_var_result);
+            // Unify lhs, rhs, and result with the SAME number type
+            _ = try self.unify(num_var, lhs_var);
+            _ = try self.unify(num_var, rhs_var);
+            _ = try self.unify(num_var, result_var);
 
             return does_fx;
         },
diff --git a/src/check/problem.zig b/src/check/problem.zig
index 2d8b96574b..0ba3a47204 100644
--- a/src/check/problem.zig
+++ b/src/check/problem.zig
@@ -320,7 +320,11 @@ pub const ReportBuilder = struct {
         try snapshot_writer.write(types.expected_snapshot);
         const owned_expected = try report.addOwnedString(self.buf.items[0..]);
 
-        const region = self.can_ir.store.regions.get(@enumFromInt(@intFromEnum(types.actual_var)));
+        // For annotation mismatches, we want to highlight the expression that doesn't match,
+        // not the annotation itself. When from_annotation is true and we're showing 
+        // "The type annotation says...", the expression is in expected_var.
+        const region_var = if (types.from_annotation) types.expected_var else types.actual_var;
+        const region = self.can_ir.store.regions.get(@enumFromInt(@intFromEnum(region_var)));
 
         // Add source region highlighting
         const region_info = self.module_env.calcRegionInfo(region.*);
@@ -1252,12 +1256,14 @@ pub const ReportBuilder = struct {
         try appendOrdinal(&self.buf, data.second_arg_index + 1);
         const second_arg_index = try report.addOwnedString(self.buf.items);
 
+        // The types from unification already have the correct snapshots
+        // expected = first argument, actual = second argument
         self.buf.clearRetainingCapacity();
-        try snapshot_writer.write(types.actual_snapshot);
+        try snapshot_writer.write(types.expected_snapshot);
         const first_type = try report.addOwnedString(self.buf.items);
 
         self.buf.clearRetainingCapacity();
-        try snapshot_writer.write(types.expected_snapshot);
+        try snapshot_writer.write(types.actual_snapshot);
         const second_type = try report.addOwnedString(self.buf.items);
 
         try report.document.addText("The ");
diff --git a/test/snapshots/add_var_with_spaces.md b/test/snapshots/add_var_with_spaces.md
index 5fc949161c..0806fec246 100644
--- a/test/snapshots/add_var_with_spaces.md
+++ b/test/snapshots/add_var_with_spaces.md
@@ -61,7 +61,7 @@ add2 = x + 2
 ~~~clojure
 (inferred-types
 	(defs
-		(patt @3.1-3.5 (type "Num(_size)")))
+		(patt @3.1-3.5 (type "Error")))
 	(expressions
-		(expr @3.8-3.18 (type "Num(_size)"))))
+		(expr @3.8-3.18 (type "Error"))))
 ~~~
diff --git a/test/snapshots/annotations.md b/test/snapshots/annotations.md
index 8390631919..3ec4a2ea3f 100644
--- a/test/snapshots/annotations.md
+++ b/test/snapshots/annotations.md
@@ -49,10 +49,10 @@ fail_pair_diff_types = mk_pair("1", 2)
                                ^^^  ^
 
 The first argument is of type:
-    _Num(_size)_
+    _Str_
 
 But the second argument is of type:
-    _Str_
+    _Num(_size)_
 
 `mk_pair` needs these arguments to have compatible types.
 
@@ -93,10 +93,10 @@ fail_with_implicit = mk_pair_inferred("str", 2)
                                       ^^^^^  ^
 
 The first argument is of type:
-    _Num(_size)_
+    _Str_
 
 But the second argument is of type:
-    _Str_
+    _Num(_size)_
 
 `mk_pair_inferred` needs these arguments to have compatible types.
 
diff --git a/test/snapshots/bound_type_var_no_annotation.md b/test/snapshots/bound_type_var_no_annotation.md
index 71b75f18eb..88e996b41c 100644
--- a/test/snapshots/bound_type_var_no_annotation.md
+++ b/test/snapshots/bound_type_var_no_annotation.md
@@ -33,6 +33,7 @@ main! = |_| {
 ~~~
 # EXPECTED
 UNUSED VARIABLE - bound_type_var_no_annotation.md:19:5:19:9
+TYPE MISMATCH - bound_type_var_no_annotation.md:11:18:11:19
 # PROBLEMS
 **UNUSED VARIABLE**
 Variable `pair` is not used anywhere in your code.
@@ -46,6 +47,20 @@ The unused variable is declared here:
     ^^^^
 
 
+**TYPE MISMATCH**
+This expression is used in an unexpected way:
+**bound_type_var_no_annotation.md:11:18:11:19:**
+```roc
+addOne = |n| n + 1
+```
+                 ^
+
+It is of type:
+    _Num(_size)_
+
+But you are trying to use it as:
+    _U64_
+
 # TOKENS
 ~~~zig
 KwApp(1:1-1:4),OpenSquare(1:5-1:6),LowerIdent(1:6-1:11),CloseSquare(1:11-1:12),OpenCurly(1:13-1:14),LowerIdent(1:15-1:17),OpColon(1:17-1:18),KwPlatform(1:19-1:27),StringStart(1:28-1:29),StringPart(1:29-1:50),StringEnd(1:50-1:51),CloseCurly(1:52-1:53),
@@ -262,11 +277,11 @@ main! = |_| {
 	(defs
 		(patt @3.1-3.9 (type "_arg -> _ret"))
 		(patt @7.1-7.8 (type "a, b -> (a, b)"))
-		(patt @11.1-11.7 (type "U64 -> U64"))
-		(patt @13.1-13.6 (type "_arg -> U64")))
+		(patt @11.1-11.7 (type "Error -> Error"))
+		(patt @13.1-13.6 (type "_arg -> Error")))
 	(expressions
 		(expr @3.12-3.17 (type "_arg -> _ret"))
 		(expr @7.11-7.42 (type "a, b -> (a, b)"))
-		(expr @11.10-11.19 (type "U64 -> U64"))
-		(expr @13.9-25.2 (type "_arg -> U64"))))
+		(expr @11.10-11.19 (type "Error -> Error"))
+		(expr @13.9-25.2 (type "_arg -> Error"))))
 ~~~
diff --git a/test/snapshots/crash_and_ellipsis_test.md b/test/snapshots/crash_and_ellipsis_test.md
index be9da8777b..4a94615816 100644
--- a/test/snapshots/crash_and_ellipsis_test.md
+++ b/test/snapshots/crash_and_ellipsis_test.md
@@ -34,7 +34,7 @@ main! = |_| {
 UNUSED VARIABLE - crash_and_ellipsis_test.md:20:5:20:12
 UNUSED VARIABLE - crash_and_ellipsis_test.md:21:5:21:12
 UNUSED VARIABLE - crash_and_ellipsis_test.md:22:5:22:12
-TYPE MISMATCH - crash_and_ellipsis_test.md:8:20:8:23
+TYPE MISMATCH - crash_and_ellipsis_test.md:9:17:11:2
 # PROBLEMS
 **UNUSED VARIABLE**
 Variable `result1` is not used anywhere in your code.
@@ -74,11 +74,12 @@ The unused variable is declared here:
 
 **TYPE MISMATCH**
 This expression is used in an unexpected way:
-**crash_and_ellipsis_test.md:8:20:8:23:**
+**crash_and_ellipsis_test.md:9:17:11:2:**
 ```roc
-testCrash : U64 -> U64
+testCrash = |_| {
+	crash "This is a crash message"
+}
 ```
-                   ^^^
 
 The type annotation says it should have the type:
     _U64_
diff --git a/test/snapshots/fuzz_crash/fuzz_crash_025.md b/test/snapshots/fuzz_crash/fuzz_crash_025.md
index 3f5a66099b..048ca833aa 100644
--- a/test/snapshots/fuzz_crash/fuzz_crash_025.md
+++ b/test/snapshots/fuzz_crash/fuzz_crash_025.md
@@ -41,7 +41,7 @@ PARSE ERROR - fuzz_crash_025.md:14:48:14:49
 PARSE ERROR - fuzz_crash_025.md:15:1:15:2
 PARSE ERROR - fuzz_crash_025.md:15:3:15:4
 PARSE ERROR - fuzz_crash_025.md:15:4:15:5
-TYPE MISMATCH - fuzz_crash_025.md:13:5:13:9
+TYPE MISMATCH - fuzz_crash_025.md:14:5:14:48
 # PROBLEMS
 **PARSE ERROR**
 Type applications require parentheses around their type arguments.
@@ -153,11 +153,11 @@ f =8
 
 **TYPE MISMATCH**
 This expression is used in an unexpected way:
-**fuzz_crash_025.md:13:5:13:9:**
+**fuzz_crash_025.md:14:5:14:48:**
 ```roc
-e : U128
+e = 3402823669209384634633746074317682114553.14: I8
 ```
-    ^^^^
+    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 The type annotation says it should have the type:
     _U128_
diff --git a/test/snapshots/fuzz_crash/fuzz_crash_027.md b/test/snapshots/fuzz_crash/fuzz_crash_027.md
index 4731de5f3c..5fced2c90b 100644
--- a/test/snapshots/fuzz_crash/fuzz_crash_027.md
+++ b/test/snapshots/fuzz_crash/fuzz_crash_027.md
@@ -227,7 +227,7 @@ UNDECLARED TYPE - fuzz_crash_027.md:153:9:153:14
 INVALID IF CONDITION - fuzz_crash_027.md:50:5:50:5
 INCOMPATIBLE MATCH PATTERNS - fuzz_crash_027.md:64:2:64:2
 TYPE MISMATCH - fuzz_crash_027.md:111:2:113:3
-TYPE MISMATCH - fuzz_crash_027.md:99:9:99:38
+TYPE MISMATCH - fuzz_crash_027.md:100:9:148:2
 # PROBLEMS
 **LEADING ZERO**
 Numbers cannot have leading zeros.
@@ -920,11 +920,58 @@ But you are trying to use it as:
 
 **TYPE MISMATCH**
 This expression is used in an unexpected way:
-**fuzz_crash_027.md:99:9:99:38:**
+**fuzz_crash_027.md:100:9:148:2:**
 ```roc
-main! : List(String) -> Result({}, _)
+main! = |_| { # Yeah Ie
+	world = "World"
+	var number = 123
+	expect blah == 1
+	tag = Blue
+	return # Comd
+		tag
+
+	# Jusnt!
+
+	...
+	match_time(
+		..., #
+	)
+	some_func(
+		dbg # bug
+			42, # Aft expr
+	)
+	crash "Unreachtement
+	tag_with = Ok(number)
+	ited = "Hello, ${world}"
+	list = [
+		add_one(
+			dbg # Afin list
+e[, # afarg
+		),	456, # ee
+	]
+	for n in list {
+	line!("Adding ${n} to ${number}")
+		number = number + n
+	}
+	record = { foo: 123, bar: "Hello", baz: tag, qux: Ok(world), punned }
+	tuple = (123, "World", tag, Ok(world), (nested, tuple), [1, 2, 3])
+	m_tuple = (
+		123,
+		"World",
+		tag1,
+		Ok(world), # Thisnt
+		(nested, tuple),
+		[1, 2, 3],
+	)
+	bsult = Err(foo) ?? 12 > 5 * 5 or 13 + 2 < 5 and 10 - 1 >= 16 or 12 <= 3 / 5
+	stale = some_fn(arg1)?.statod()?.ned()?.recd?
+	Stdoline!(
+		"How about ${ #
+			Num.toStr(number) # on expr
+		} as a",
+	)
+} # Commenl decl
 ```
-        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 The type annotation says it should have the type:
     _List(Error) -> Result({  }, _d)_
diff --git a/test/snapshots/issue/underscore_error_propagation.md b/test/snapshots/issue/underscore_error_propagation.md
index d42ac357f9..d769755f7e 100644
--- a/test/snapshots/issue/underscore_error_propagation.md
+++ b/test/snapshots/issue/underscore_error_propagation.md
@@ -23,7 +23,7 @@ goodValue = "test"
 ~~~
 # EXPECTED
 UNDERSCORE IN TYPE ALIAS - underscore_error_propagation.md:1:1:1:1
-TYPE MISMATCH - underscore_error_propagation.md:14:13:14:24
+TYPE MISMATCH - underscore_error_propagation.md:15:13:15:19
 # PROBLEMS
 **UNDERSCORE IN TYPE ALIAS**
 Underscores are not allowed in type alias declarations.
@@ -38,11 +38,11 @@ Underscores in type annotations mean "I don't care about this type", which doesn
 
 **TYPE MISMATCH**
 This expression is used in an unexpected way:
-**underscore_error_propagation.md:14:13:14:24:**
+**underscore_error_propagation.md:15:13:15:19:**
 ```roc
-goodValue : GoodDerived
+goodValue = "test"
 ```
-            ^^^^^^^^^^^
+            ^^^^^^
 
 The type annotation says it should have the type:
     _GoodDerived_
diff --git a/test/snapshots/lambda_annotation_mismatch_error.md b/test/snapshots/lambda_annotation_mismatch_error.md
index 65de349cbb..91f0021428 100644
--- a/test/snapshots/lambda_annotation_mismatch_error.md
+++ b/test/snapshots/lambda_annotation_mismatch_error.md
@@ -17,6 +17,7 @@ wrong_type_function = |x| x * 3.14
 ~~~
 # EXPECTED
 TYPE MISMATCH - lambda_annotation_mismatch_error.md:5:23:5:24
+TYPE MISMATCH - lambda_annotation_mismatch_error.md:9:31:9:35
 # PROBLEMS
 **TYPE MISMATCH**
 This expression is used in an unexpected way:
@@ -32,6 +33,20 @@ It is of type:
 But you are trying to use it as:
     _Num(_size)_
 
+**TYPE MISMATCH**
+This expression is used in an unexpected way:
+**lambda_annotation_mismatch_error.md:9:31:9:35:**
+```roc
+wrong_type_function = |x| x * 3.14
+```
+                              ^^^^
+
+It is of type:
+    _Frac(_size)_
+
+But you are trying to use it as:
+    _I64_
+
 # TOKENS
 ~~~zig
 KwModule(1:1-1:7),OpenSquare(1:8-1:9),LowerIdent(1:9-1:24),Comma(1:24-1:25),LowerIdent(1:26-1:45),CloseSquare(1:45-1:46),
@@ -116,8 +131,8 @@ NO CHANGE
 (inferred-types
 	(defs
 		(patt @5.1-5.16 (type "Error -> Error"))
-		(patt @9.1-9.20 (type "I64 -> I64")))
+		(patt @9.1-9.20 (type "Error -> Error")))
 	(expressions
 		(expr @5.19-5.29 (type "Error -> Error"))
-		(expr @9.23-9.35 (type "I64 -> I64"))))
+		(expr @9.23-9.35 (type "Error -> Error"))))
 ~~~
diff --git a/test/snapshots/lambda_capture/lambda_invalid_references.md b/test/snapshots/lambda_capture/lambda_invalid_references.md
index 533a9d7e86..28e9dcc95c 100644
--- a/test/snapshots/lambda_capture/lambda_invalid_references.md
+++ b/test/snapshots/lambda_capture/lambda_invalid_references.md
@@ -72,5 +72,5 @@ NO CHANGE
 ~~~
 # TYPES
 ~~~clojure
-(expr @1.1-1.14 (type "Num(_size) -> _arg -> Num(_size2)"))
+(expr @1.1-1.14 (type "Error -> _arg -> Error"))
 ~~~
diff --git a/test/snapshots/lambda_multi_arg_mismatch.md b/test/snapshots/lambda_multi_arg_mismatch.md
index a205ad8457..52af6c8a9f 100644
--- a/test/snapshots/lambda_multi_arg_mismatch.md
+++ b/test/snapshots/lambda_multi_arg_mismatch.md
@@ -79,10 +79,10 @@ The first and third arguments to `multi_arg_fn` must have compatible types, but
     ^^^^^^^
 
 The first argument is of type:
-    _Str_
+    _Num(_size)_
 
 But the third argument is of type:
-    _Num(_size)_
+    _Str_
 
 `multi_arg_fn` needs these arguments to have compatible types.
 
diff --git a/test/snapshots/lambda_parameter_unused.md b/test/snapshots/lambda_parameter_unused.md
index ab567640b4..f6fb8dd94f 100644
--- a/test/snapshots/lambda_parameter_unused.md
+++ b/test/snapshots/lambda_parameter_unused.md
@@ -34,6 +34,7 @@ main! = |_| {
 # EXPECTED
 UNUSED VARIABLE - lambda_parameter_unused.md:5:8:5:14
 UNDERSCORE VARIABLE USED - lambda_parameter_unused.md:9:22:9:29
+TYPE MISMATCH - lambda_parameter_unused.md:9:32:9:33
 # PROBLEMS
 **UNUSED VARIABLE**
 Variable `unused` is not used anywhere in your code.
@@ -59,6 +60,20 @@ multiply = |_factor| _factor * 2
                      ^^^^^^^
 
 
+**TYPE MISMATCH**
+This expression is used in an unexpected way:
+**lambda_parameter_unused.md:9:32:9:33:**
+```roc
+multiply = |_factor| _factor * 2
+```
+                               ^
+
+It is of type:
+    _Num(_size)_
+
+But you are trying to use it as:
+    _U64_
+
 # TOKENS
 ~~~zig
 KwApp(1:1-1:4),OpenSquare(1:5-1:6),LowerIdent(1:6-1:11),CloseSquare(1:11-1:12),OpenCurly(1:13-1:14),LowerIdent(1:15-1:17),OpColon(1:17-1:18),KwPlatform(1:19-1:27),StringStart(1:28-1:29),StringPart(1:29-1:50),StringEnd(1:50-1:51),CloseCurly(1:52-1:53),
@@ -305,15 +320,15 @@ main! = |_| {
 ~~~clojure
 (inferred-types
 	(defs
-		(patt @5.1-5.4 (type "U64 -> U64"))
-		(patt @9.1-9.9 (type "U64 -> U64"))
-		(patt @13.1-13.8 (type "U64 -> U64"))
-		(patt @17.1-17.7 (type "U64 -> U64"))
-		(patt @19.1-19.6 (type "_arg -> Num(_size)")))
+		(patt @5.1-5.4 (type "Error -> Error"))
+		(patt @9.1-9.9 (type "Error -> Error"))
+		(patt @13.1-13.8 (type "Error -> Error"))
+		(patt @17.1-17.7 (type "Error -> Error"))
+		(patt @19.1-19.6 (type "_arg -> Error")))
 	(expressions
-		(expr @5.7-5.18 (type "U64 -> U64"))
-		(expr @9.12-9.33 (type "U64 -> U64"))
-		(expr @13.11-13.23 (type "U64 -> U64"))
-		(expr @17.10-17.27 (type "U64 -> U64"))
-		(expr @19.9-25.2 (type "_arg -> Num(_size)"))))
+		(expr @5.7-5.18 (type "Error -> Error"))
+		(expr @9.12-9.33 (type "Error -> Error"))
+		(expr @13.11-13.23 (type "Error -> Error"))
+		(expr @17.10-17.27 (type "Error -> Error"))
+		(expr @19.9-25.2 (type "_arg -> Error"))))
 ~~~
diff --git a/test/snapshots/lambda_ret_constraint_bug.md b/test/snapshots/lambda_ret_constraint_bug.md
index 991abab23e..953dd30537 100644
--- a/test/snapshots/lambda_ret_constraint_bug.md
+++ b/test/snapshots/lambda_ret_constraint_bug.md
@@ -14,9 +14,22 @@ main : I64, I64 -> I64
 main = |_, _| helper(5)
 ~~~
 # EXPECTED
-NIL
+TYPE MISMATCH - lambda_ret_constraint_bug.md:4:18:4:19
 # PROBLEMS
-NIL
+**TYPE MISMATCH**
+This expression is used in an unexpected way:
+**lambda_ret_constraint_bug.md:4:18:4:19:**
+```roc
+helper = |n| n * 2
+```
+                 ^
+
+It is of type:
+    _Num(_size)_
+
+But you are trying to use it as:
+    _I64_
+
 # TOKENS
 ~~~zig
 KwApp(1:1-1:4),OpenSquare(1:5-1:6),LowerIdent(1:6-1:10),CloseSquare(1:10-1:11),OpenCurly(1:12-1:13),LowerIdent(1:14-1:16),OpColon(1:16-1:17),KwPlatform(1:18-1:26),StringStart(1:27-1:28),StringPart(1:28-1:45),StringEnd(1:45-1:46),CloseCurly(1:47-1:48),
@@ -112,9 +125,9 @@ NO CHANGE
 ~~~clojure
 (inferred-types
 	(defs
-		(patt @4.1-4.7 (type "I64 -> I64"))
-		(patt @7.1-7.5 (type "I64, I64 -> I64")))
+		(patt @4.1-4.7 (type "Error -> Error"))
+		(patt @7.1-7.5 (type "Error, Error -> Error")))
 	(expressions
-		(expr @4.10-4.19 (type "I64 -> I64"))
-		(expr @7.8-7.24 (type "I64, I64 -> I64"))))
+		(expr @4.10-4.19 (type "Error -> Error"))
+		(expr @7.8-7.24 (type "Error, Error -> Error"))))
 ~~~
diff --git a/test/snapshots/let_polymorphism_complex.md b/test/snapshots/let_polymorphism_complex.md
index b79f18b139..2b523427bc 100644
--- a/test/snapshots/let_polymorphism_complex.md
+++ b/test/snapshots/let_polymorphism_complex.md
@@ -1083,7 +1083,7 @@ main = |_| {
 		(patt @85.1-85.9 (type "Num(_size)"))
 		(patt @86.1-86.9 (type "List(Num(_size))"))
 		(patt @87.1-87.9 (type "{ base: Num(_size), derived: List(Num(_size2)) }"))
-		(patt @90.1-90.6 (type "{ numbers: { value: Num(_size), list: List(Num(_size2)), float: Frac(_size3) }, strings: { value: Str, list: List(Str) }, empty_lists: { raw: List(Num(_size4)), in_list: List(List(Num(_size5))), in_record: { data: List(Num(_size6)) } }, computations: { from_num: Num(_size7), from_frac: Num(_size8), list_from_num: List(Num(_size9)) } }"))
+		(patt @90.1-90.6 (type "{ numbers: { value: Num(_size), list: List(Num(_size2)), float: Frac(_size3) }, strings: { value: Str, list: List(Str) }, empty_lists: { raw: List(Num(_size4)), in_list: List(List(Num(_size5))), in_record: { data: List(Num(_size6)) } }, computations: { from_num: Num(_size7), from_frac: Frac(_size8), list_from_num: List(Num(_size9)) } }"))
 		(patt @105.1-105.5 (type "_arg -> Num(_size)")))
 	(expressions
 		(expr @4.7-4.9 (type "Num(_size)"))
@@ -1112,6 +1112,6 @@ main = |_| {
 		(expr @85.12-85.19 (type "Num(_size)"))
 		(expr @86.12-86.22 (type "List(Num(_size))"))
 		(expr @87.12-87.59 (type "{ base: Num(_size), derived: List(Num(_size2)) }"))
-		(expr @90.9-103.2 (type "{ numbers: { value: Num(_size), list: List(Num(_size2)), float: Frac(_size3) }, strings: { value: Str, list: List(Str) }, empty_lists: { raw: List(Num(_size4)), in_list: List(List(Num(_size5))), in_record: { data: List(Num(_size6)) } }, computations: { from_num: Num(_size7), from_frac: Num(_size8), list_from_num: List(Num(_size9)) } }"))
+		(expr @90.9-103.2 (type "{ numbers: { value: Num(_size), list: List(Num(_size2)), float: Frac(_size3) }, strings: { value: Str, list: List(Str) }, empty_lists: { raw: List(Num(_size4)), in_list: List(List(Num(_size5))), in_record: { data: List(Num(_size6)) } }, computations: { from_num: Num(_size7), from_frac: Frac(_size8), list_from_num: List(Num(_size9)) } }"))
 		(expr @105.8-108.2 (type "_arg -> Num(_size)"))))
 ~~~
diff --git a/test/snapshots/let_polymorphism_numbers.md b/test/snapshots/let_polymorphism_numbers.md
index cf65292381..513f43bf5f 100644
--- a/test/snapshots/let_polymorphism_numbers.md
+++ b/test/snapshots/let_polymorphism_numbers.md
@@ -247,29 +247,29 @@ main = |_| {
 ~~~clojure
 (inferred-types
 	(defs
-		(patt @4.1-4.4 (type "Num(_size)"))
+		(patt @4.1-4.4 (type "Frac(_size)"))
 		(patt @5.1-5.5 (type "Frac(_size)"))
-		(patt @8.1-8.8 (type "Num(_size)"))
+		(patt @8.1-8.8 (type "Frac(_size)"))
 		(patt @9.1-9.10 (type "Frac(_size)"))
-		(patt @12.1-12.8 (type "Num(_size)"))
-		(patt @13.1-13.13 (type "Num(_size)"))
-		(patt @16.1-16.10 (type "Num(_size)"))
-		(patt @17.1-17.15 (type "Num(_size)"))
+		(patt @12.1-12.8 (type "Frac(_size)"))
+		(patt @13.1-13.13 (type "Frac(_size)"))
+		(patt @16.1-16.10 (type "Frac(_size)"))
+		(patt @17.1-17.15 (type "Frac(_size)"))
 		(patt @20.1-20.7 (type "Num(_size) -> Num(_size2)"))
 		(patt @23.1-23.12 (type "Num(_size)"))
-		(patt @24.1-24.14 (type "Num(_size)"))
-		(patt @26.1-26.5 (type "_arg -> Num(_size)")))
+		(patt @24.1-24.14 (type "Frac(_size)"))
+		(patt @26.1-26.5 (type "_arg -> Frac(_size)")))
 	(expressions
-		(expr @4.7-4.9 (type "Num(_size)"))
+		(expr @4.7-4.9 (type "Frac(_size)"))
 		(expr @5.8-5.11 (type "Frac(_size)"))
-		(expr @8.11-8.14 (type "Num(_size)"))
+		(expr @8.11-8.14 (type "Frac(_size)"))
 		(expr @9.13-9.17 (type "Frac(_size)"))
-		(expr @12.11-12.19 (type "Num(_size)"))
-		(expr @13.16-13.23 (type "Num(_size)"))
-		(expr @16.13-16.23 (type "Num(_size)"))
-		(expr @17.18-17.27 (type "Num(_size)"))
+		(expr @12.11-12.19 (type "Frac(_size)"))
+		(expr @13.16-13.23 (type "Frac(_size)"))
+		(expr @16.13-16.23 (type "Frac(_size)"))
+		(expr @17.18-17.27 (type "Frac(_size)"))
 		(expr @20.10-20.19 (type "Num(_size) -> Num(_size2)"))
 		(expr @23.15-23.24 (type "Num(_size)"))
-		(expr @24.17-24.28 (type "Num(_size)"))
-		(expr @26.8-29.2 (type "_arg -> Num(_size)"))))
+		(expr @24.17-24.28 (type "Frac(_size)"))
+		(expr @26.8-29.2 (type "_arg -> Frac(_size)"))))
 ~~~
diff --git a/test/snapshots/match_expr/single_branch.md b/test/snapshots/match_expr/single_branch.md
index 7c2353fb93..d9e1ce92ab 100644
--- a/test/snapshots/match_expr/single_branch.md
+++ b/test/snapshots/match_expr/single_branch.md
@@ -65,5 +65,5 @@ match value {
 ~~~
 # TYPES
 ~~~clojure
-(expr @1.1-3.2 (type "Num(_size)"))
+(expr @1.1-3.2 (type "Error"))
 ~~~
diff --git a/test/snapshots/match_expr/tag_with_payload.md b/test/snapshots/match_expr/tag_with_payload.md
index 441e9eb52e..21b16b10be 100644
--- a/test/snapshots/match_expr/tag_with_payload.md
+++ b/test/snapshots/match_expr/tag_with_payload.md
@@ -115,5 +115,5 @@ match shape {
 ~~~
 # TYPES
 ~~~clojure
-(expr @1.1-5.2 (type "Num(_size)"))
+(expr @1.1-5.2 (type "Frac(_size)"))
 ~~~
diff --git a/test/snapshots/match_expr/variable_shadowing.md b/test/snapshots/match_expr/variable_shadowing.md
index 0987b85bfb..7f73bd5db4 100644
--- a/test/snapshots/match_expr/variable_shadowing.md
+++ b/test/snapshots/match_expr/variable_shadowing.md
@@ -111,5 +111,5 @@ match (value, other) {
 ~~~
 # TYPES
 ~~~clojure
-(expr @1.1-4.2 (type "Num(_size)"))
+(expr @1.1-4.2 (type "Error"))
 ~~~
diff --git a/test/snapshots/plume_package/Color.md b/test/snapshots/plume_package/Color.md
index 1a9bbc5b42..8dad6c9e4c 100644
--- a/test/snapshots/plume_package/Color.md
+++ b/test/snapshots/plume_package/Color.md
@@ -81,7 +81,7 @@ is_named_color = |str|{
 UNUSED VARIABLE - Color.md:30:5:30:25
 UNDEFINED VARIABLE - Color.md:68:14:68:27
 INVALID NOMINAL TAG - Color.md:23:5:23:33
-TYPE MISMATCH - Color.md:26:7:26:46
+TYPE MISMATCH - Color.md:27:7:46:2
 # PROBLEMS
 **UNUSED VARIABLE**
 Variable `is_char_in_hex_range` is not used anywhere in your code.
@@ -115,7 +115,7 @@ I'm having trouble with this nominal tag:
     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 The tag is:
-    _RGBA(U8, U8, U8, Num(_size))_
+    _RGBA(U8, U8, U8, Frac(_size))_
 
 But it should be one of:
     _[Hex(Str), Named(Str), RGB(U8, U8, U8), RGBA(U8, U8, U8, Dec)]_
@@ -126,11 +126,29 @@ But it should be one of:
 
 **TYPE MISMATCH**
 This expression is used in an unexpected way:
-**Color.md:26:7:26:46:**
+**Color.md:27:7:46:2:**
 ```roc
-hex : Str -> Result(Color, [InvalidHex(Str)])
+hex = |str| {
+
+    bytes = str.to_utf8()
+    is_char_in_hex_range = |b| (b >= '0' and b <= '9') or (b >= 'a' and b <= 'f') or (b >= 'A' and b <= 'F')
+
+    match bytes {
+        ['#', a, b, c, d, e, f] => {
+            is_valid =
+                a.is_char_in_hex_range()
+                and b.is_char_in_hex_range()
+                and c.is_char_in_hex_range()
+                and d.is_char_in_hex_range()
+                and e.is_char_in_hex_range()
+                and f.is_char_in_hex_range()
+
+            if is_valid Ok(Color.Hex(str)) else Err(InvalidHex("Expected Hex to be in the range 0-9, a-f, A-F, got ${str}"))
+        }
+        _ => Err(InvalidHex("Expected Hex must start with # and be 7 characters long, got ${str}"))
+    }
+}
 ```
-      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 The type annotation says it should have the type:
     _Str -> Result(Error, [InvalidHex(Str)])_
diff --git a/test/snapshots/simple_lambda_constraint_success.md b/test/snapshots/simple_lambda_constraint_success.md
index b9a174655e..afbf7dcd5f 100644
--- a/test/snapshots/simple_lambda_constraint_success.md
+++ b/test/snapshots/simple_lambda_constraint_success.md
@@ -16,8 +16,23 @@ addTwoF64 : F64 -> F64
 addTwoF64 = |x| x + 2.0
 ~~~
 # EXPECTED
+TYPE MISMATCH - simple_lambda_constraint_success.md:5:18:5:19
 TYPE MISMATCH - simple_lambda_constraint_success.md:9:17:9:18
 # PROBLEMS
+**TYPE MISMATCH**
+This expression is used in an unexpected way:
+**simple_lambda_constraint_success.md:5:18:5:19:**
+```roc
+addTwo = |x| x + 2
+```
+                 ^
+
+It is of type:
+    _Num(_size)_
+
+But you are trying to use it as:
+    _I64_
+
 **TYPE MISMATCH**
 This expression is used in an unexpected way:
 **simple_lambda_constraint_success.md:9:17:9:18:**
@@ -115,9 +130,9 @@ NO CHANGE
 ~~~clojure
 (inferred-types
 	(defs
-		(patt @5.1-5.7 (type "I64 -> I64"))
+		(patt @5.1-5.7 (type "Error -> Error"))
 		(patt @9.1-9.10 (type "Error -> Error")))
 	(expressions
-		(expr @5.10-5.19 (type "I64 -> I64"))
+		(expr @5.10-5.19 (type "Error -> Error"))
 		(expr @9.13-9.24 (type "Error -> Error"))))
 ~~~
diff --git a/test/snapshots/type_anno_connection.md b/test/snapshots/type_anno_connection.md
index 2731d78adf..8df3dd6417 100644
--- a/test/snapshots/type_anno_connection.md
+++ b/test/snapshots/type_anno_connection.md
@@ -14,9 +14,22 @@ my_number : U64
 my_number = add_one(42)
 ~~~
 # EXPECTED
-NIL
+TYPE MISMATCH - type_anno_connection.md:4:19:4:20
 # PROBLEMS
-NIL
+**TYPE MISMATCH**
+This expression is used in an unexpected way:
+**type_anno_connection.md:4:19:4:20:**
+```roc
+add_one = |x| x + 1
+```
+                  ^
+
+It is of type:
+    _Num(_size)_
+
+But you are trying to use it as:
+    _U64_
+
 # TOKENS
 ~~~zig
 KwModule(1:1-1:7),OpenSquare(1:8-1:9),LowerIdent(1:9-1:16),Comma(1:16-1:17),LowerIdent(1:18-1:27),CloseSquare(1:27-1:28),
@@ -90,9 +103,9 @@ NO CHANGE
 ~~~clojure
 (inferred-types
 	(defs
-		(patt @4.1-4.8 (type "U64 -> U64"))
-		(patt @7.1-7.10 (type "U64")))
+		(patt @4.1-4.8 (type "Error -> Error"))
+		(patt @7.1-7.10 (type "Error")))
 	(expressions
-		(expr @4.11-4.20 (type "U64 -> U64"))
-		(expr @7.13-7.24 (type "U64"))))
+		(expr @4.11-4.20 (type "Error -> Error"))
+		(expr @7.13-7.24 (type "Error"))))
 ~~~
diff --git a/test/snapshots/type_annotation_basic.md b/test/snapshots/type_annotation_basic.md
index 1393606281..c2ab320836 100644
--- a/test/snapshots/type_annotation_basic.md
+++ b/test/snapshots/type_annotation_basic.md
@@ -35,6 +35,7 @@ main! = |_| {
 ~~~
 # EXPECTED
 UNUSED VARIABLE - type_annotation_basic.md:21:5:21:9
+TYPE MISMATCH - type_annotation_basic.md:13:18:13:19
 # PROBLEMS
 **UNUSED VARIABLE**
 Variable `pair` is not used anywhere in your code.
@@ -48,6 +49,20 @@ The unused variable is declared here:
     ^^^^
 
 
+**TYPE MISMATCH**
+This expression is used in an unexpected way:
+**type_annotation_basic.md:13:18:13:19:**
+```roc
+addOne = |n| n + 1
+```
+                 ^
+
+It is of type:
+    _Num(_size)_
+
+But you are trying to use it as:
+    _U64_
+
 # TOKENS
 ~~~zig
 KwApp(1:1-1:4),OpenSquare(1:5-1:6),LowerIdent(1:6-1:11),CloseSquare(1:11-1:12),OpenCurly(1:13-1:14),LowerIdent(1:15-1:17),OpColon(1:17-1:18),KwPlatform(1:19-1:27),StringStart(1:28-1:29),StringPart(1:29-1:50),StringEnd(1:50-1:51),CloseCurly(1:52-1:53),
@@ -276,11 +291,11 @@ main! = |_| {
 	(defs
 		(patt @5.1-5.9 (type "a -> a"))
 		(patt @9.1-9.8 (type "a, b -> (a, b)"))
-		(patt @13.1-13.7 (type "U64 -> U64"))
-		(patt @15.1-15.6 (type "_arg -> U64")))
+		(patt @13.1-13.7 (type "Error -> Error"))
+		(patt @15.1-15.6 (type "_arg -> Error")))
 	(expressions
 		(expr @5.12-5.17 (type "a -> a"))
 		(expr @9.11-9.42 (type "a, b -> (a, b)"))
-		(expr @13.10-13.19 (type "U64 -> U64"))
-		(expr @15.9-27.2 (type "_arg -> U64"))))
+		(expr @13.10-13.19 (type "Error -> Error"))
+		(expr @15.9-27.2 (type "_arg -> Error"))))
 ~~~
diff --git a/test/snapshots/type_app_complex_nested.md b/test/snapshots/type_app_complex_nested.md
index 7675302b11..b3014335dc 100644
--- a/test/snapshots/type_app_complex_nested.md
+++ b/test/snapshots/type_app_complex_nested.md
@@ -33,7 +33,7 @@ UNDECLARED TYPE - type_app_complex_nested.md:4:30:4:35
 UNDECLARED TYPE - type_app_complex_nested.md:4:51:4:56
 UNUSED VARIABLE - type_app_complex_nested.md:7:12:7:21
 UNDECLARED TYPE - type_app_complex_nested.md:12:14:12:19
-TYPE MISMATCH - type_app_complex_nested.md:12:55:12:56
+TYPE MISMATCH - type_app_complex_nested.md:13:18:15:2
 # PROBLEMS
 **UNDECLARED TYPE**
 The type _Maybe_ is not declared in this scope.
@@ -104,11 +104,12 @@ deepNested : Maybe(Result(List(Dict(Str, a)), _b)) -> a
 
 **TYPE MISMATCH**
 This expression is used in an unexpected way:
-**type_app_complex_nested.md:12:55:12:56:**
+**type_app_complex_nested.md:13:18:15:2:**
 ```roc
-deepNested : Maybe(Result(List(Dict(Str, a)), _b)) -> a
+deepNested = |_| {
+	crash "not implemented"
+}
 ```
-                                                      ^
 
 The type annotation says it should have the type:
     _a_
diff --git a/test/snapshots/type_var_underscore_conventions.md b/test/snapshots/type_var_underscore_conventions.md
index 793cfd27ed..efeadd7768 100644
--- a/test/snapshots/type_var_underscore_conventions.md
+++ b/test/snapshots/type_var_underscore_conventions.md
@@ -34,7 +34,7 @@ UNUSED VARIABLE - type_var_underscore_conventions.md:9:22:9:26
 UNUSED VARIABLE - type_var_underscore_conventions.md:13:17:13:18
 UNUSED VARIABLE - type_var_underscore_conventions.md:17:17:17:18
 UNUSED VARIABLE - type_var_underscore_conventions.md:22:9:22:10
-TYPE MISMATCH - type_var_underscore_conventions.md:8:36:8:41
+TYPE MISMATCH - type_var_underscore_conventions.md:9:28:9:37
 # PROBLEMS
 **UNUSED VARIABLE**
 Variable `x` is not used anywhere in your code.
@@ -98,11 +98,11 @@ main = |x| "done"
 
 **TYPE MISMATCH**
 This expression is used in an unexpected way:
-**type_var_underscore_conventions.md:8:36:8:41:**
+**type_var_underscore_conventions.md:9:28:9:37:**
 ```roc
-ending_underscore : List(elem_) -> elem_
+ending_underscore = |list| "default"
 ```
-                                   ^^^^^
+                           ^^^^^^^^^
 
 The type annotation says it should have the type:
     _elem__